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Georg Carl Friedrich Kunowski

2025-03-31T21:29:05Z

Jstuby: /* Astronom */

[[Datei:Georg Carl Friedrich Kunowski.jpg|mini|Georg Carl Friedrich Kunowski um 1840]]
'''Georg Carl Friedrich Kunowski''' (* [[3. März]] [[1786]] in [[Bytom Odrzański|Beuthen]]; † [[22. Dezember]] [[1846]] in [[Węgliniec|Kohlfurt]]) war Justizkommissionsrat und Standesreformer, Brückenbauer, Topograph und Geologe, Astronom, Theatersyndikus in Berlin sowie Eisenbahnsyndikus.

== Familie ==
Georg Carl Friedrich war ein Sohn des evangelischen Pastors Primarius [[George August Kunowski]] und dessen Ehefrau Johanna Christiane Charlotte, geborene Henrici. Er hatte insgesamt neun Geschwister, darunter [[Eduard von Kunowski|Georg August Eduard]] (1795–1870), und Georg Moritz (1802–1866). Mit seiner Frau hatte er sechs Kinder.

== Ausbildung ==
Kunowski besuchte das Gymnasium in [[Świdnica|Schweidnitz]], wo sein Vater Georg August die Stellung eines königlichen Kreisinspektors innehatte. Am 11. Mai 1803 begann er das Studium, wie schon sein Vater, an der [[Martin-Luther-Universität Halle-Wittenberg|Universität Halle]] an der juristischen Fakultät. Friedrich musste aber schon nach eineinhalbjährigem Studium im Oktober 1806 die Universität verlassen, nachdem [[Napoléon Bonaparte|Napoléon]] dieselbe nach einem Schusswechsel mit Studenten auflöste. Er ging zunächst nach Schweidnitz zurück und erlebte dort in seinem Vaterhaus die Belagerung und Übergabe der Festung Schweidnitz durch die nachgerückten Franzosen. Er ging im Jahre 1807 nach Berlin und lebte dort vorübergehend bei seinem Onkel Georg Friedrich Kunowski, Kriegsrat und Expedient im preußischen Justizministerium, der seine Studien bis zu ihrem Abschluss förderte. Friedrich absolvierte dort kurz nacheinander die beiden ersten juristischen Examen.

== Privatleben ==
Kunowski hatte sich während dieser Zeit in Luise Leopoldine Eleonore, die Tochter seines Onkels verliebt. Sie heirateten am 12. August 1812 und lebten danach gemeinsam in Lewin in der [[Grafschaft Glatz]].

== Berufliche Entwicklung ==
=== Justizrat ===
Im Jahre 1809 wurde Kunowski als Assessor beim Stadtgericht zu Schweidnitz eingestellt. Nach bestandenem dritten Examen 1811 wechselte er als Assessor an das Oberlandesgericht in Glogau, das für das westliche Niederschlesien zuständig war, angestellt. Am 19. Februar 1813 wurde der Sitz des Gerichts nach [[Legnica|Liegnitz]] verlegt, kurz vor dem Ausbruch der [[Befreiungskriege]].

1814 erhielt Friedrich eine Anstellung in Berlin, wohl auf Veranlassung seines Onkels. Aus Berlin verlautete am 23. Juli folgendes: Der bisherige Oberlandes-Gerichts-Assessor Georg Carl Friedrich Kunowski zu Liegnitz ist als Justiz-Kommissarius und [[Notar|Notarius Publicus]] bei dem königlichen [[Kammergericht]] angestellt worden.

Am 26. Juni 1819 wurde Friedrich als einer von fünf zum Anwalt am [[Rheinischer Revisions- und Kassationshof|Revisions- und Kassationshof]] für die [[Rheinprovinz]]en in Berlin zugelassen. Der in der Klosterstraße 76 angesiedelte Kassationshof entschied in dritter und letzter Instanz über die Bestätigung oder Aufhebung von Urteilen. Am 11. Februar 1823 wurde er zum Justizkommissionsrat ernannt und hat danach bis 1834 seinen Tätigkeitsschwerpunkt vom Kammergericht zum Berliner Stadtgericht verlegt.

Neben seiner richterlichen Tätigkeit war er als Advokat in zahlreiche wichtige [[Zivilprozess]]e eingebunden, wie beispielsweise
* die Testamentsvollziehung und die damit verbundene Vormundschaft über den Prinzen Adolph zu Hohenlohe,
* die Testamentsvollziehung des Reichskanzlers Fürst Hardenberg;
* die Wiederaufnahme und Einleitung des historisch gewordenen Prozesses der Familie von Schwerin gegen die preußische Regierung wegen der Herausgabe der [[Festung Spantekow]] in Pommern, der Abschluss eines Vertrages hierüber mit dem Staate und eines Vergleichs der Familienglieder unter sich,
* die Gründung einiger großer Hüttenwerke in Schlesien, namentlich der Laura-Hütte und der Hütten derer von Winckler,
* der Prozess des Bankiers [[Wilhelm Christian Benecke von Gröditzberg]] (1779–1860),
* die Unterhandlungen der Gläubiger des vormaligen [[Königreich Westphalen|Königreichs Westphalen]] mit den Regierungen von Preußen und Hannover
* der Prozess [[Arthur Schopenhauer]] gegen Marquet

=== Juristischer Standesreformer ===
Kunowski hat sich mit seinen Kollegen vom Jahre 1841 an engagiert um die Stärkung des Rechtsanwaltsstandes bemüht, insbesondere hinsichtlich einer adäquaten Ausbildung und Berufspraxis, die bis dahin in der „Allgemeinen Gerichtsordnung vom 6. Juli 1793“ geregelt war.

Die [[standesrecht]]lichen Verbesserungen, die im Rahmen eines angeforderten umfangreichen Gutachtens gegenüber dem Minister des Königs im Dezember 1841 im Einzelnen eingefordert wurden, beschreiben den bestehenden Missstand, auf einen kurzen Nenner gebracht:
# „dass wir Richter (aus-)bilden, aber keine Advokaten“
# „dass der beste Richter selten ein guter Advokat ist“.

Die Verbesserungsvorschläge wurden erst nach dem Tod von Kunowski 1846 zumindest teilweise durch die erlassene „Verordnung über die Bildung eines Ehrenraths unter den Justizkommissarien, Advokaten und Notaren“ vom 30. April 1847 umgesetzt. In vollem Umfang wurde die vorgeschlagenen [[standesrecht]]lichen Verbesserungen der Advokaten schließlich durch die am 1. Juli 1878 eingeführte [[Rechtsanwaltsordnung]] auf Reichsebene eingeführt. Für seine Verdienste im Zusammenhang mit den Vorschlägen zur Standesrechtsreform, niedergelegt im „Dezember-Gutachten“ von 1841, erhielt Kunowski vom König den [[Roter Adlerorden|Roten Adlerorden]] III. Klasse mit Schleife.

== Kunowski-Brücke ==
Während seiner anwaltlichen Tätigkeit hatte er seinen Dienstsitz in Berlin in der Rochstraße 1, den er 1829 bezogen hatte. Dazu gehörte auch das Haus im Süden Ecke [[Neue Friedrichstraße]] 34 (ab 1951 [[Littenstraße]]). An dem Haus Rochstraße war eine Zeit lang auch der Pächter und Architekt Johann Albert Roch (* 1786 in Breslau; † 1825 in Berlin), beteiligt. Roch baute 1825 im Auftrag von Friedrich aus privaten Mitteln die Straße. Dazu wurde eine [[Gusseisen|gusseiserne]] Gewölbebrücke über den [[Festung Berlin#Festungsgräben|Königsgraben]] im Verlauf der Rochstraße an der Einmündung in die heutige Dircksenstraße errichtet. Sie stellte als Nord-Südpassage die Verbindung zum Stadtgebiet her. Bei ihrer Fertigstellung am 8. Mai 1825 erhielt sie den Namen Kunowski-Brücke. Mit der Errichtung war den Erbauern ein Recht für achtzig Jahre eingeräumt worden, ein [[Maut|Brückengeld]] für Wagen und Personen zu erheben. Die entsprechenden Münzen werden noch heute im antiquarischen Handel angeboten. – Die Brücke wurde 1879 abgerissen, weil der Königsgraben zum Bau der Berliner Stadtbahn zugeschüttet wurde.<ref>Eckhard Thiemann, Dieter Deszyk, Horstpeter Metzing: ''Berlin und seine Brücken.'' Jaron Verlag, Berlin 2003, ISBN 3-89773-073-1, S. 178.</ref>

== Topograph und Geologe ==
Schon in seiner Jugend hatte sich Georg Carl Friedrich Kunowski für Naturwissenschaften, insbesondere Geologie und Astrologie, interessiert und besuchte an der Universität Halle zusätzliche Vorlesungen zur Geologie (damals: [[Geognosie]]) des Naturforschers Steffens. Hier lernte er an der juristischen Fakultät seinen Kommilitonen, den späteren Geologen und Historiker [[Karl Georg von Raumer (Geologe)|Karl Georg von Raumer]] (1783–1865) kennen, der ihn zu eigener Forschungsarbeit auf dem Gebiet der Genealogie und Mineralogie in der Provinz Schlesien ermutigte. Im Rahmen seiner Forschungen sammelte er Mineralien auf Wanderungen in den Sudeten, dem schlesischen Mittelgebirge und dem Berg Zubten in der Nähe seiner Heimatstadt Schweidnitz.

Mit dem Herausgeber [[Karl Konrad Streit]] (1757–1826) kam er überein, die Ergebnisse seiner Forschungsarbeit fortlaufend zwischen 1810 und 1813 in den Schlesischen Provinzialblättern am Ende in einer Gesamtstärke von 113 Seiten zu veröffentlichen.

Karl Georg von Raumer benutzte die Erkenntnisse über die von ihm gesammelten Mineralien in einer geographischen Beschreibung von Schlesien.

Später schenkte Kunowski dem Gymnasium Schweidnitz seine umfangreiche Mineraliensammlung.

== Astronom ==
Durch seinen beruflichen Wechsel nach Berlin im Jahre 1814 waren die Möglichkeiten der [[Geologie|geologischen]] Forschung in den [[Sudeten]] stark eingeschränkt. Trotz der beruflichen Herausforderung in seiner neuen Position als Richter und Notar sowie den familiären Verpflichtungen einer inzwischen fünfköpfigen Familie begann er sich den Jugendtraum einer [[Astronomie|astronomischen]] Betätigung zu erfüllen.

Er stand in gutem Einvernehmen mit dem Direktor der [[Berliner Sternwarte|Königlichen Sternwarte in Berlin]], [[Johann Elert Bode]] (1747–1826), der seine astronomischen Vorstellungen wesentlich prägte und beeinflusste und ihn indirekt zur Anschaffung eines sehr effektiven Fernrohrs bei [[Joseph von Fraunhofer|Fraunhofer]] in München veranlasste, das Bode bereits fünf Jahre zuvor im Jahre 1815 angeboten worden war. Das Fernrohr besaß ein achromatisches Fernrohr mit 52 [[Pariser Linie]]n Öffnung nebst Zubehör, 72 Zoll Brennweite (6 Fuß) und einem Kometenokular mit 34-facher Vergrößerung und wurde im November 1820 im Privathaus von Kunowski in der [[Friedrichstraße]] 28 aufgestellt.

Kunowskis Fernrohr lieferte bessere Ergebnisse, also schärfere Bilder etwa vom [[Mond]], [[Mars (Planet)|Mars]] oder den [[Komet]]en, als dies in der Sternwarte möglich war. Bode suchte daher vermehrt die Kunowski’sche Sternwarte auf, um seine Beobachtungen zu realisieren. Zwischen beiden Männern entwickelte sich eine Freundschaft. 1821 bezeichnete Bode Kunowski als seinen Freund.

Die bisherigen Bilder bzw. Zeichnungen von der Mondoberfläche wurden von [[Johann Hieronymus Schroeter]] Ende des 18. Jahrhunderts in [[Sternwarte Lilienthal|seinem Observatorium]] in [[Lilienthal]] bei Bremen mit Hilfe von Linsen, die Joseph Fraunhofer geliefert hatte, angefertigt. Kunowski hatte zunächst vor, diese Bilder zu vervollständigen und die noch nicht gezeichneten Gegenden zu ergänzen. Das aber, so schreibt Kunowski, kommt einer herkulischen Arbeit gleich, da mir die optische Schärfe und Lichtstärke meines Fernrohrs so ganz eigentlich unzählbare Gegenstände, die Schroeter weder beschrieben noch gezeichnet hat, darbietet, dass mir sehr oft zum Zeichnen und Nachtragen der Mut (und vermutlich die Zeit als Hobbyastronom) fehlt.

[[Datei:Kunowsky crater AS12-52-7746.jpg|mini|Mondkrater Kunowsky, aufgenommen von Apollo 12]]
Die Ergebnisse der Beobachtungen Kunowskis hat Bode in dem von ihm herausgegebenen [[Berliner Astronomisches Jahrbuch|Jahrbuch für Astronomie]] veröffentlicht. Hierzu gehört unter anderem die Entdeckung verschiedener [[Mondkrater]], von denen der [[Kunowsky (Mondkrater)|Krater Kunowsky]] ihm zu Ehren seinen Namen trägt. Neben den Erkenntnissen über die Oberfläche des Mondes sind wichtige Entdeckungen auch auf den Planeten gemacht worden. Georg Carl Friedrich gehörte zu den ersten, die mit dem Fraunhofer-Fernrohr Einzelheiten in der gebotenen Schärfe erkennen konnten. Die bisher als Wolken beschriebenen veränderlichen dunklen Flecken des Mars hat er mit Hilfe des Fernrohrs innerhalb einer Beobachtungsperiode von vier Monaten als unveränderliche Marsflecken bestimmt, die kennzeichnend für die typischen dunklen Strukturen an der [[Äquator]]zone sind. Anhand dessen konnte er die Rotationszeit des Mars erstmals mit hoher Präzision ermitteln, wobei der von ihm festgestellte Wert nur um 43 Sekunden von dem tatsächlichen Wert abweicht.

Er hat vom Mars die in der Literatur bekannten Zeichnungen angefertigt, aber auf Grund vieler beruflicher und privater Verpflichtungen aus Zeitgründen seine Beobachtungen wie auch die des Mondes nicht kartographisch festgehalten. Hierum haben sich schließlich die Berliner Astronomen [[Johann Heinrich Mädler]] (1794–1870) und [[Wilhelm Beer (Astronom)|Wilhelm Beer]] (1797–1850) bemüht, die 1831 die erste Marskarte veröffentlichten und dabei die Erkenntnisse Kunowskis über die Unveränderlichkeit der Marsflecke bestätigten. 1837 folgte die erste nach den neuen Erkenntnissen entwickelte Mondkarte.

Mit Wilhelm Beer verband Kunowski ein enges fachliches und gutes privates Verhältnis. Kunowski hatte sein Interesse an der Astronomie geweckt. Für seine späteren Forschungen hatte Beer in seiner Villa im Tiergarten eine eigene Sternwarte eingerichtet. Beide waren darüber hinaus (siehe Abschnitt: [[#Syndikus Königsstädtisches Theater Berlin|Syndikus Königsstädtisches Theater Berlin]]) als Teilhaber in der Direktion des Königstädtischen Theaters tätig und wirkten später zugleich als [[Syndikus]] in verschiedenen Berliner Bahngesellschaften.

[[Datei:Lspn comet halley.jpg|mini|Halleyscher Komet]]
Neben dem Planeten Mars richtete sich Kunowskis Interesse auf die Beobachtung von Kometen, die zugleich einen Schwerpunkt seiner astronomischen Betätigung bildete. Er war neben den Astronomen [[Johann Franz Encke]] (1791–1865), [[Carl Friedrich Gauß|Gauß]] und [[Heinrich Wilhelm Olbers|Olbers]] mit der Bestimmung von Kometenbahnen befasst. Im Astronomischen Jahrbuch 1826 berichtete Bode, dass er nach vergeblicher Suche des nach Encke benannten Kometen am 14. September 1822 die genaue Position und den Bahnverlauf von Kunowski mitgeteilt bekommen habe. Encke folgte nach dem Tod von Bode 1826 als Direktor der Berliner Sternwarte. Teilweise mit Encke gemeinsam hat Kunowski mit dem Fraunhofer-Fernrohr, das technisch der Ausstattung der Sternwarte zum Teil überlegen war, in seinem Privathaus aufsehenerregende Beobachtungen gemacht. In den Astronomischen Nachrichten wird berichtet, dass beide den [[Enckescher Komet|Enckeschen Kometen]] bereits am 7. Oktober 1828 gesehen haben. Ferner berichtete Encke, dass der [[Halleyscher Komet]] Kunowski mit seinem vortrefflichen Fernrohr in der Nacht vom 21. auf den 22. August 1835 nach 76-jähriger Wiederkehr überraschend früh, zunächst als schwachen Nebelfleck, wiederentdeckt wurde. Er war im Kometensucher der Sternwarte noch nicht zu erkennen. Einen Tag später bemerkten ihn die Herren Beer und Mädler in ihrem Fernrohr. Die größte Erdnähe hatte der Komet am 16. November 1835, danach wieder am 20. April 1910 und 9. Februar 1986.

Beruflich bedingt schränkte Kunowski seine astronomischen Forschungen in der Folgezeit aufgrund von richterlichen und insbesondere anwaltlichen Verpflichtungen in bedeutenden Prozessen stärker ein. Hinzu kam ein weiteres Betätigungsfeld, das ihn mehr als ein Jahrzehnt lang intensiv in Anspruch nahm.

== Syndikus Königsstädtisches Theater Berlin ==
[[Datei:Königsstädtisches Theater.jpg|mini|Das Königsstädtische Theater]]
Neben den beiden bestehenden Hofbühnen sollte in Berlin ein drittes Theater entstehen, das nach dem Vorbild des 1781 gegründeten [[Theater in der Leopoldstadt|Wiener Vorstadttheaters in der Leopoldstadt]] konzipiert und mit privaten Mitteln finanziert werden sollte. Für die Gründung eines solchen Theaters behielt sich der preußische Hof das Recht der [[Konzession]]serteilung vor. Dahinter stand, dass man in Berlin ängstlich darauf bedacht war, dass sich das neue Volkstheater der Konzession entsprechend aus dem Repertoire der beiden königlichen Bühnen heraushält.

Am 13. Mai 1822 wurde die Entscheidung zur Errichtung des [[Königsstädtisches Theater|Königsstädtischen Theaters]] am [[Alexanderplatz]] durch Kabinettsorder von [[Friedrich Wilhelm III. (Preußen)|Friedrich Wilhelm III.]] verkündet. Die Konzession erhielt der bis dahin in Berlin unbekannte [[Karl Friedrich Cerf]], dem damit die Verantwortung für den Aufbau und die Organisation dieses Theaters übertragen wurde. Dieser schaltete den pensionierten Schauspieler [[Heinrich Eduard Bethmann]] (1774–1857) in seine Bemühungen ein, geeignete Persönlichkeiten für das Theaterprojekt zu finden. Bethmann gewann Georg Carl Friedrich Kunowski für dieses Projekt.

Zur Errichtung des Theaters war die Gründung eines [[Aktiengesellschaft|Actienvereins]] vorgesehen, über den zunächst die erforderlichen Mittel für die Finanzierung und die Unterhaltung des Theaters beschafft werden sollten. Hierfür gewannen Bethmann und Kunowski eine Reihe von geachteten und begüterten Berliner Bürgern. Am 23. September 1822 wurde das Theater gegründet, am 13. Dezember 1822 wurden die Statuten des Actienvereins in Form des sog. Grundvertrags beschlossen.

Der preußische Hof stimmte dem Finanzierungskonzept zu, nach dem durch die Ausgabe von 400 Aktien insgesamt 120000 [[Taler]] für den Bau des Theaters bereitgestellt werden sollten. Innerhalb weniger Monate wurde die Summe beschafft. Kunowski selbst hatte einen Anteil von 6.000 Thalern übernommen. Der Auftrag für den Bau des Theaters wurde [[Carl Theodor Ottmer]] (1800–1843) erteilt, einem Schüler des bekannten Berliner Architekten [[Carl Friedrich Schinkel]] (1781–1841).

Einschließlich der beiden Initiatoren Bethmann und Kunowski wurde in der Generalversammlung vom 23. September 1822 ein siebenköpfiges Direktorium für die Führung der Geschäfte gewählt. Bethmann übernahm die spezielle Leitung der Theaterverwaltung, der Justizkommissar Kunowski wurde mit der „Direction des Bureau Geschäfts“ und der Führung des [[Syndikat]]s der Gesellschaft betraut. Er war verantwortlich für die Unterrichtung der Öffentlichkeit, die Führung des Korrespondenz, alle Rechtsgeschäfte, die Handhabung der Disziplin und die Prüfung neuer Stücke im Abgleich mit der Konzession. Neben Bethmann und Kunowski gehörten dem Gremium fünf Mitglieder an, und zwar die Bankiers [[Jakob Herz Beer]] bzw. nach dessen Tod Kunowskis guter Bekannter [[Wilhelm Beer (Astronom)|Wilhelm Beer]] (1797–1850), [[Wilhelm Christian Benecke von Gröditzberg]] (1779–1860), [[Joseph Maximilian Fränckel]] (1788–1857), [[Alexander Mendelssohn]] (1798–1871) und [[Johann David Müller]]. Im April 1824 schied Bethmann wegen Meinungsverschiedenheiten vor allem mit Kunowski wenige Monate vor der Eröffnung aus dem Direktorium aus. Danach übernahm Kunowski vorübergehend seine Ämter und hatte damit die Gesamtleitung des Unternehmens inne. Gleichzeitig fiel ihm die Rolle Theaterzensors zu, eine Ämterhäufung, die für Private Bühnen ungewöhnlich war. Seitdem wurde vermutet, dass er möglicherweise im Auftrag des Fürsten von Wittgenstein, des für Theaterfragen zuständigen preußischen Ministers gehandelt habe, was jedoch jeder Grundlage entbehrte.

Zur Mitte des Jahres 1824 wurde der Theaterbau fertiggestellt. Die Eröffnungsveranstaltung fand am 4. August 1824 in Anwesenheit des Königs und seiner Familie statt. Die Erwartungen waren überaus hoch, der Andrang riesig, schrieb [[Karoline Bauer]] in ihren Erinnerungen. Sie selbst hielt die Eröffnungsrede anlässlich dieses Ereignisses und erhielt hierfür uneingeschränkten Beifall.
Die Eröffnungsstücke weckten beim Publikum Begeisterung.

Die erste Spielzeit war geprägt durch beliebte Stücke aus den Befreiungskriegen und alte bekannte Possen. Auf dem Spielplan standen etwa „[[Minna von Barnhelm]]“, „[[Doktor und Apotheker]]“ von [[Carl Ditters von Dittersdorf]]. Als erfolgreiche Stückedichter wurden [[Louis Angely]] und [[Karl von Holtei]] (1798–1880) für das Theater gewonnen. Holtei (mit der Posse „Ein Trauerspiel in Berlin“), bereits seit 1823 am Theater erfolgreich als Stückeschreiber erfolgreich tätig, nahm im Jahre 1825 das ihm von „seinem Gönner“ Kunowski unterbreitete Angebot zur Übernahme der Position des Theaterdirektors und -dichters trotz mehrerer Konkurrenzofferten an, was zumindest innerhalb der ersten drei Jahre seiner Aktivitäten sicher zum Wohle des Theaters gereichte.

Im Laufe der Zeit wirkten sich jedoch die durch die Konzession auferlegten Beschränkungen der künstlerischen Betätigung des Königsstädtischen Theaters auf die Motivation, die Stimmung in der Theaterleitung und den Geschäftserfolg zunehmend negativ aus. Hinzu traten ständige Auseinandersetzungen mit dem [[Carl Graf von Brühl]], der als [[Generalintendant]] der königlichen Bühnen akribisch darüber wachte, dass das Königsstädtische Theater sich eng in den Grenzen der zugeteilten Theaterkonzession bewegte und nicht in das Repertoire der beiden Königlichen Schauspielhäuser eingriff. Alle Versuche, mit dem König eine Erweiterung des künstlerischen Freiraums auszudehnen, wurden abgelehnt. In dieser Situation versuchte man, kompetenten externen Rat einzuholen. So bat Georg Carl Friedrich Kunowski am 12. März 1827 [[Johann Wolfgang von Goethe]] wie folgt um eine Präzisierung des Gattungsbegriffes [[opera buffa]]: „Das Königstädtische Theater ist durch die vom König ihm erteilte Konzession beschränkt und angewiesen auf das kleine Schauspiel und Lustspiel, die Posse und Parodie, auf das Melodram, das kleinere Singspiel insofern es zur opera buffa gehört.“ Goethe kannte Kunowski vor allem durch seine eindrucksvollen Forschungsergebnisse in der Astronomie. Ferner war Goethe informiert über das Bauvorhaben Königsstädtisches Theater, was ihn im Detail interessierte. Er kannte auch Kunowskis Veröffentlichung ''Die Verwaltung des Königsstädtischen Theaters'', Berlin 1826, auf die Goethe in seiner Antwort vom 28. April 1827 auch einging. Da Goethe mit Graf Brühl gut bekannt war, bat er Kunowski um Verständnis dafür, dass er sich in die Theaterstreitigkeit nicht einmischen wolle.
Im Übrigen war er an dem Bau des Königsstädtischen Theaters interessiert, weil das Theater in Weimar kurz zuvor 1825 einen Brand erlebt hatte und erneuert werden musste.

In dieser schwierigen Situation, in der sich das Königsstädter Theater zu dieser Zeit befand, brachte ein glücklicher Umstand zumindest vorübergehend Entspannung: In [[Wien]] wurde die Italienische Oper, eine der Vorstadtbühnen, aus finanziellen Gründen geschlossen. Kunowski erfuhr, dass die hier tätigen Künstler ihre Anstellung verloren hatten, unter ihnen die bekannte junge Sängerin [[Henriette Sontag]] (1803–1854). Kunowski machte sich selbst auf die Reise, und es gelang ihm sie mitsamt ihrer Mutter und Schwester während einer Theater-Tournée in Deutschland für das Königsstädtische Theater zu gewinnen und unter Vertrag zu nehmen. Sie trat zum ersten Male am 3. August 1825 in Berlin auf und löste Begeisterungsstürme aus. Ihr sängerisches Talent sorgte zwei Jahre lang für ausverkaufte Veranstaltungen. Schon lange erwartet, kam sie am 4. September 1826 auch nach [[Weimar]] und besuchte dort Goethe: „Demoiselle Sontag sang unvergleichlich“, notierte Goethe in sein Tagebuch.

Nach der anfänglichen Sontag-Euphorie wurden die Probleme der Themenbeschränkung wieder sichtbar. Kunowski wies frühzeitig darauf hin, dass ein Verlust von Henriette Sontag wegen der bekannten Querelen die Entwicklung des Theaters massiv benachteiligen würde. Der König blieb, vertreten durch den Grafen Brühl bei seiner ablehnenden Haltung, das Repertoire des Theater weiter zu öffnen für Stücke, die der königlichen Bühne vorbehalten blieben. Den bevorstehenden Bankrott, der nach dem Abgang von Sontag unvermeidlich schien, nahm [[Friedrich Wilhelm III. (Preußen)|Friedrich Wilhelm III. von Preußen]] offenbar in Kauf. Henriette Sontag gab schließlich auf. Sie verabschiedete sich 1827 nach zwei Jahren vom Ensemble und dem Berliner Publikum.

Am 14. Mai erklären die Aktionäre die Auflösung des Vereins. Sie erfolgte faktisch am 19. Oktober 1829. In einer Veröffent-lichung von 1830 „Circulare an die Herren Actionaire“ berichtet Kunowski über die Auflösungsverhandlungen zwischen dem Theater-Direktorium, vertreten durch Cerf, und den Aktionären des Theaters, die er anwaltlich vertrat vor dem Stadtgericht Berlin, die vom Mai 1829 bis zum Oktober 1830 andauerten. Offenbar schon vor den Bankrott war Carl Friedrich Cerf wieder als Strohmann aufgebaut worden, um die Anteile mit finanziellen Mitteln des Königs zurückzuerwerben. Cerf wurde danach vom König aus bisher nicht nachvollziehbaren Gründen mit dem gesamten Aktienkapital ausgestattet und als Verwalter des Theaters mit einer lebenslangen Rente eingesetzt. Er starb 1845. 1851 verfügte König [[Friedrich Wilhelm IV.|Friedrich Wilhelm IV. von Preußen]] die Schließung des Theaters.

== Syndikus Berlin-Hamburger Eisenbahn ==
[[Datei:B-HH-Bahn-Map.jpg|mini|Streckenführung der Berlin-Hamburger Bahn]]
Neben seiner Vorliebe für die Astronomie und seinem Engagement beim Königsstädter Theater verband Kunowski mit Wilhelm Beer das gemeinsame Interesse an infrastrukturellen Fragen, konkret einem funktionsfähigen Eisenbahnnetz, das in Preußen im Aufbau war. Beer war als [[Syndikus]] an Eisenbahngesellschaften beteiligt, die die Verbindung zwischen Berlin und Breslau, Magdeburg und Anhalt unterhielten.

Georg Carl Friedrich Kunowski trat 1840 an die Spitze eines Eisenbahnprojekts, das eine schnelle Verbindung zwischen Berlin und Hamburg ([[Berlin-Hamburger Bahn]]) zum Ziel hatte und vor allem von führenden Handelshäusern in Berlin favorisiert wurde. Hierfür war eine Trasse rechts der Elbe bestens geeignet, die sich letztlich auch unter militärischen Aspekten besser als die dichter besiedelte linke Seite eignete. Nach längerem Tauziehen, ob rechts oder links der Elbe, gab der König dem für die Durchführung des Projekts verantwortlichen Komitee seine Zustimmung zu dem geplanten Vorhaben rechts der Elbe.

Schließlich trat die „Generalversammlung zur Constituierung der Berlin-Hamburger Eisenbahngesellschaft“ in [[Schwerin]] zusammen und beschloss unter Federführung von Georg Carl Friedrich Kunowski die Statuten der Gesellschaft. Die Eisenbahntrasse war 1844 in ihrem Verlauf rechtsverbindlich definiert. Die preußische Regierung erteilte am 28. Februar 1845 die Genehmigung für den Bau, der danach unmittelbar in Angriff genommen wurde. Es wurden Teilstrecken eröffnet, zwischen Berlin und [[Boizenburg/Elbe]]. Die gesamte Strecke war am 15. Dezember 1846 fertiggestellt.

Kurz zuvor war die Verbindung zwischen Berlin und [[Breslau]] in Betrieb genommen worden, ein Projekt, bei dem sein alter Bekannter Wilhelm Beer den stellvertretenden Vorsitz hatte. Auf seinem Wege in die Lausitz zusammen mit seiner 19-jährigen Tochter Charlotte Wilhelmine Emma entschied sich Kunowski für die Beförderung mit diesem Transportmittel. Auf der Strecke nördlich von Kohlfurt löste sich Hinterachse des zweiachsigen Postwagens. Er wurde herausgeschleudert und starb an einem Schlaganfall.

Kunowski wurde auf dem [[Friedhöfe vor dem Halleschen Tor|Friedhof I der Jerusalems- und Neuen Kirche]] in Berlin beigesetzt. Das Grab ist nicht erhalten.<ref>[[Hans-Jürgen Mende (Historiker)|Hans-Jürgen Mende]]: ''Lexikon Berliner Begräbnisstätten''. Pharus-Plan, Berlin 2018, ISBN 978-3-86514-206-1, S. 214.</ref>

== Mitgliedschaften ==
Die [[Gesellschaft naturforschender Freunde]] wurde 1773 von [[Friedrich Heinrich Wilhelm Martini]] gegründet. Sie hatte monatlich zwei Sitzungen in der Französischen Straße 25 und war auf zwölf Mitglieder beschränkt. Oberstes Ziel war die Förderung der [[Naturgeschichte]]. Georg Carl Friedrich Kunowski wurde 1823 von Bode als lebenslanges Ehrenmitglied eingeführt.

Kunowski war bei der Gründung der [[Gesellschaft für Erdkunde]] durch den Berliner Professor [[Carl Ritter]] am 7. Juni 1828 anwesend. Er hielt aus diesem Anlass einen Vortrag über die Ergebnisse seiner Beobachtungen der [[Sonnenfleck]]e. Er war zusammen mit seinem Bruder Eduard, dem späteren preußischen [[General der Infanterie]], Mitglied der Gesellschaft.

Seit Oktober 1834 gehörte Kunowski dem 1749 von [[Pastor Schulthess]] gegründeten [[Montagsclub]] an, der monatlich und mit Gästen einmal pro Quartal in dem angesehenen [[Englisches Haus (Berlin)|Englischen Haus]] in der [[Mohrenstraße (Berlin)|Mohrenstraße]] 49 zusammentraf. Eingeführt hatte ihn der mit ihm befreundete Prof. Encke, der dem Montagsclub bereits seit 1826 angehörte.

Dieser Kreis bestand aus einer Mitgliederzahl von 30 bekannten Persönlichkeiten aus der bürgerlichen Bildungselite. Er verfolgte keine politischen Ziele. Stattdessen wurde heitere und unbefangene Konversation gepflegt.

1830 wurde Kunowski Mitglied der [[Gesetzlose Gesellschaft zu Berlin|Gesetzlosen Gesellschaft zu Berlin]], die 1809 mit dem Anspruch gegründet wurde, ohne Statuten und Regelungen auszukommen, abgesehen von Regeln für die Zulassung ihrer Mitglieder. Sie gehörten vorwiegend der aufgeklärten politischen und kulturellen Elite an.

Seit der Gründung des [[Aktienverein Zoologischer Garten|Actienvereins Zoologischer Garten]] am 1. Dezember 1844 gehörte Georg Carl Friedrich Kunowski vier Monate nach Eröffnung des Tierparks dem Verein an. Er wurde in der ersten Generalversammlung am 2. Juni 1845 in den Vorstand und zum Justiziar des Vereins gewählt.

== Nachwirken ==
Kunowski wurde am 29. Dezember 1846 auf den Halleschen Friedhöfen beigesetzt. Das Grab geriet später in Vergessenheit und wurde geschleift.

Sein astronomisches Labor wurde aufgelöst. Sein Fernrohr wurde der preußischen Regierung zum Erwerb angeboten. 1847 wurde der Ankauf wegen angeblich leerer Staatskassen abgelehnt. Am 7. Juli 1853 gelang der Verkauf zu einem Preis von 1500 [[Reichstaler]]n über den zuständigen Minister [[Karl Otto von Raumer]] für das physikalische Kabinett der [[Humboldt-Universität zu Berlin|Berliner Universität]], dessen Leiter Prof. Dr. Magnus war.

Kunowskis Bruder, der spätere General Eduard von Kunowski war der Witwe des Verstorbenen, Eleonore (1789–1862), bei der praktischen Abwicklung vieler Nachlassangelegenheiten trotz seiner beruflichen Verpflichtungen behilflich. Für die umfangreiche Nachlassordnung stellte sich Kunowskis Neffe [[Otto Friedrich Leopold von Kunowski]] (1824–1907), damals erst 23-jährig, gelernter Jurist mit Referendarexamen und späterer Oberlandesgerichtspräsident in Breslau (1887), Wirklicher Geheimer Justizrat und Excellenz (1895), zur Verfügung.

Der Mondkrater [[Kunowsky (Mondkrater)|Kunowsky]] ist nach ihm benannt. Ein von ihm entdeckter [[Marskrater]] von 67 km Durchmesser – mit den Koordinaten 57,1° N und 9,7° W – wurde von der [[Internationale Astronomische Union|Internationalen Astronomischen Union]] 1973 ebenfalls nach ihm benannt.

== Veröffentlichungen ==
* ''Beiträge zur Topographie und Naturhistorie der Sudeten.'' In: ''Schlesische Provinzialblätter.'' Jahrgang 1813.
* ''Der Zobtenberg.'' daselbst.
* ''Die Verwaltung des Königstädtischen Theaters in ihrer Beziehung zu dem pens. Hofschauspieler H. L. Bethmann.'' Berlin 1926.
* ''Stellungnahme.'' In: ''Vossischen Zeitung.'' Nr. 186 vom 10. August 1824.
* Deutsches Literaturarchiv, Marbach, Briefe Kunowskis an Cotta (Johann Friedrich Cotta von Cottendorf)
* ''Einige physische Beobachtungen des Mondes, des Saturns, und Mars.'' Astronomisches Jahrbuch für 1825 (Berlin 1822).

== Literatur ==
* {{ADB|17|388|388|Kunowsky, Georg Karl Friedrich|Siegmund Günther|ADB:Kunowsky, Georg Karl Friedrich}}
* ''Augsburger Allgemeine Zeitung'', 24. Dezember 1846
* Karl Gustav Heinrich Berner: ''Schlesische Landsleute: Ein Gedenkbuch hervorragender, in Schlesien geborener Männer und Frauen aus der Zeit von 1180 bis zur Gegenwart.'' Leipzig 1901.
* Jürgen Blunck: ''Georg Carl Friedrich Kunowski, Anwalt, Naturwissenschaftler, Theater- und Eisenbahngeschichte.'' In: ''Berlin in Geschichte und Gegenwart. Jahrbuch des Landesarchivs Berlin.'' Berlin 1998, S. 27 ff.
* Jürgen Blunck, Christian Rieckher: ''Georg Carl Friedrich Kunowski, Ein Jurist am Fernrohr.'' In: ''Sterne und Weltraum'', 1998, Nr. 37, S. 124 ff.
* Gustav E. Sachse, Eduard Droop (Hrsg.): ''Der Montagsklub in Berlin 1749-1899.'' Fest- und Gedenkschrift zu seiner 150sten Jahrfeier Berlin 1899.
* Willi Eylitz: ''Das Königstädtische Theater in Berlin.'' Diss.-Vorlage Rostock 1940.
* {{LuiseBMS |Autor=Ruth Freydank |Titel=Hier wurde Nante geboren. Geschichte des Königsstädtischen Theaters |ID=prob |Nr=10 |Jahr=1998 |Seite=4–15}}
* ''Haude und Spenersche Zeitung'', 3. Dezember 1842 und 21. Dezember 1846.
* Heinz Georg Klös: ''Die Arche Noah an der Spree.'' 1994.
* Heinz Kullnick: ''Berliner und Wahlberliner: Personen und Persönlichkeiten in Berlin von 1640–1960.'' Berlin ca. 1960.
* [[Karlheinz Muscheler]]: ''Die Schopenhauer-marquet-Prozesse und das Preussische Recht.'' 1996.
* ''Neuer Neokrolog der Deutschen.'' Jg. 24, 1846 (1848).
* Johann C. Poggendorff: ''Biographisch-literarisches Handwörterbuch zur Geschichte der exacten Wissenschaften: enthaltend Nachweisungen über Lebensverhältnisse und Leistungen von Mathematikern, Astronomen, Physikern, Chemikern, Mineralogen, Geologen usw. aller Völker und Zeiten.'' Leipzig 1863, Band I: ''A–L.'' Band II: ''M–Z.''
* [[Karl von Holtei]]: ''40 Jahre Lorbeerstab und Eichenkranz.''
* William Sheehan: ''The Planet Mars: A History of Observation and Discovery.'' Chapter 4: ''Areographers.'' University of Arizona press.
* Harald Kunowski: ''200 Jahre Königsstädtisches Theater in Berlin''. Band 1: ''Kabale und Resignation, Geschichte des Aktienvereins''. E-Book. [[Books on Demand]], Norderstedt 2023, ISBN 978-3-7578-0036-9.

== Weblinks ==
{{Commonscat|George K. Kunowsky|audio=0|video=0}}


== Einzelnachweise ==
<references responsive />

{{Normdaten|TYP=p|GND=136214908|VIAF=80598481}}

{{SORTIERUNG:Kunowski, Georg Carl Friedrich}}
[[Kategorie:Geologe (19. Jahrhundert)]]
[[Kategorie:Astronom (19. Jahrhundert)]]
[[Kategorie:Richter (deutsche Geschichte)]]
[[Kategorie:Verwaltungsjurist]]
[[Kategorie:Notar (Deutschland)]]
[[Kategorie:Rechtsanwalt (Deutschland)]]
[[Kategorie:Person als Namensgeber für einen Marskrater]]
[[Kategorie:Person als Namensgeber für einen Mondkrater]]
[[Kategorie:Träger des Roten Adlerordens 3. Klasse]]
[[Kategorie:Deutscher]]
[[Kategorie:Geboren 1786]]
[[Kategorie:Gestorben 1846]]
[[Kategorie:Mann]]

{{Personendaten
|NAME=Kunowski, Georg Carl Friedrich
|ALTERNATIVNAMEN=Kunowsy, Georg Karl Friedrich
|KURZBESCHREIBUNG=deutscher Jurist, Astronom, Topograph und Geologe
|GEBURTSDATUM=3. März 1786
|GEBURTSORT=[[Bytom Odrzański|Beuthen]]
|STERBEDATUM=22. Dezember 1846
|STERBEORT=[[Węgliniec|Kohlfurt]]
}}

Kunowsky (Mondkrater)

2025-03-31T21:28:12Z

Jstuby:

{{Infobox Mondkrater
|FeatureId=3161
|Name=Kunowsky
|Bild=Kepler + Encke - LROC - WAC.JPG
|Bildtext=Kunowsky (unten rechts) und Umgebung ([[LROC]]-WAC)
|Breitengrad=3.2
|Längengrad=-32.54
|Durchmesser=18.27
|Tiefe=860
|TiefeRef=<ref>John E. Westfall: ''Atlas of the Lunar Terminator.'' Cambridge University Press, Cambridge u. a. 2000, ISBN 0-521-59002-7.</ref>
|Typ=
|LAC=57
|BenanntNach=[[Georg Carl Friedrich Kunowski]] (1786–1846)
|BenanntJahr=1935
}}
[[Datei:Kunowsky crater AS12-52-7746.jpg|mini|Mondkrater Kunowsky, aufgenommen von Apollo 12]]
'''Kunowsky''' ist ein [[Einschlagkrater]] auf der westlichen [[Mondvorderseite]] am Rand des [[Mare Insularum]]. Er liegt südöstlich des Kraters [[Kepler (Mondkrater)|Kepler]] und südwestlich von [[Copernicus (Mondkrater)|Copernicus]].

Das Kraterinnere ist von den Laven des umgebenden [[Mare (Mond)|Mare]] überflutet, sodass eine flache Kraterebene von einem relativ niederem, kaum erodiertem Rand umgeben ist.

{{Nebenkrater/Tabellenkopf|Kunowsky}}
{{Nebenkrater|Kunowsky|C|-0.22|-32.42|3.64|10452}}
{{Nebenkrater|Kunowsky|D|1.52|-28.88|5.22|10453}}
{{Nebenkrater|Kunowsky|G|1.67|-30.83|3.37|10454}}
{{Nebenkrater|Kunowsky|H|1.1|-30.02|3.02|10455}}
{{Nebenkrater/Tabellenende}}

Der Krater wurde 1935 von der [[Internationale Astronomische Union|IAU]] nach dem deutschen Astronomen [[Georg Carl Friedrich Kunowski]] offiziell benannt.

== Weblinks ==
* {{PlanetaryNames|3161|Kunowsky}}
* {{MoonWiki}}

== Einzelnachweise ==
{{Commonscat|Kunowsky (lunar crater)|audio=0|video=0}}
<references />

[[Kategorie:Einschlagkrater (Mond)]]

Gassendi (Mondkrater)

2021-12-01T03:02:20Z

Jstuby:

{{Infobox Mondkrater
|FeatureId=2111
|Name=Gassendi
| Bild = AS16-120-19295 (22005244941).jpg
| Bildtext = Kraterrand des Gassendi
|Breitengrad=-17.5
|Längengrad=-39.98
|Durchmesser=109.58
|Tiefe=
|TiefeRef=
|Typ=
|LAC=93
|BenanntNach=[[Pierre Gassendi]] (1592–1655)
|BenanntJahr=1935
}}
[[Datei:Tycho Crater.jpg|mini|Der große Krater Gassendi (links, im streifenden Licht) am Rande des dunklen Mare Nubium. Das Strahlensystem des Kraters [[Tycho (Mondkrater)|Tycho]] (unten) reicht mit seinen Ausläufern bis fast hierher]]

'''Gassendi''' ist ein großer [[Mondkrater]] im südwestlichen Quadranten des [[Erdmond]]es. Die [[Wallebene]] hat einen Durchmesser von rund 110 km und ist durch zahlreiche [[Hügel]] und [[Mondrille]]n sowie einige hohe [[Zentralberg]]e charakterisiert. Er liegt am Westrand des leicht gewellten [[Mare Nubium]] und direkt nördlich des [[Mare Humorum]].

Der Kraterrand ist stark [[Erosion (Geologie)|erodiert]] und im Norden durch den jüngeren Krater '''Gassendi A''' unterbrochen. Gassendi und seine Zentralberge sind im streifenden Licht – etwa 3 Tage nach [[Mondphase|Halbmondphase]] – zu sehen; Ein erstaunlich vielfältiges Objekt, auch schon im kleinen Fernrohr (Vier- bis Achtzöller).

* [[Selenografische Koordinaten]] der Kratermitte: 17° 36' Süd, 40° 06' West
* benannt nach dem französischen [[Naturwissenschaftler]] und Mathematiker [[Pierre Gassendi]] (1592–1655).

{{Nebenkrater/Tabellenkopf}}
{{Nebenkrater|Gassendi|A|-15.55|320.19|32.22|9353}}
{{Nebenkrater|Gassendi|B|-14.66|319.34|24.66|9354}}
{{Nebenkrater|Gassendi|E|-18.45|316.37|7.14|9355}}
{{Nebenkrater|Gassendi|F|-15.03|314.97|8.05|9356}}
{{Nebenkrater|Gassendi|G|-16.75|315.33|7.35|9357}}
{{Nebenkrater|Gassendi|J|-21.63|322.87|9.11|9358}}
{{Nebenkrater|Gassendi|K|-18.8|316.27|6.13|9359}}
{{Nebenkrater|Gassendi|L|-20.4|318.2|5.55|9360}}
{{Nebenkrater|Gassendi|M|-18.61|320.83|3.07|9361}}
{{Nebenkrater|Gassendi|N|-18.07|320.65|3.89|9362}}
{{Nebenkrater|Gassendi|O|-21.97|324.84|10.34|9363}}
{{Nebenkrater|Gassendi|P|-17.31|319.23|2.34|9364}}
{{Nebenkrater|Gassendi|R|-21.95|322.13|4.28|9365}}
{{Nebenkrater|Gassendi|T|-19.07|324.54|9.53|9366}}
{{Nebenkrater|Gassendi|W|-17.66|316.27|6.36|9367}}
{{Nebenkrater|Gassendi|Y|-20.91|321.46|5|9368}}
{{Nebenkrater/Tabellenende}}

== Weblinks ==
* {{PlanetaryNames|2111|Gassendi}}
* [http://www.skytrip.de/gassendi.htm SkyTrip.de: Gassendi] (deutsch)
* [[Spektrum.de]]: Amateuraufnahmen [http://www.spektrum.de/alias/wunder-des-weltalls/gassendi-krater/1396263][http://www.spektrum.de/alias/wunder-des-weltalls/von-letronne-bis-gassendi/1258495][https://www.spektrum.de/alias/wunder-des-weltalls/rima-herigonius/1696352][https://www.spektrum.de/alias/wunder-des-weltalls/krater-gassendi-und-rimae-mersenius/1548981]

[[Kategorie:Einschlagkrater (Mond)]]

Mondgestein

2017-03-21T19:35:40Z

Jstuby:

[[Datei:Lunar Ferroan Anorthosite (60025).jpg|miniatur|Apollo-Probe #60025, aufgesammelt durch [[Apollo 16]] und gegenwärtig im ''National Museum of Natural History'' in [[Washington, D.C.|Washington, D. C.]], ausgestellt.]]
'''Mondgestein''' ist [[Gestein]], das auf dem [[Mond]] (Erdmond) entstanden ist. Der Begriff wird ebenso für andere Materialien gebraucht, die während der Erkundung des Mondes aufgesammelt wurden.
[[File:3,34 Milliarden Jahre altes Mondgestein.jpg|thumb|3,34 Milliarden Jahre altes Mondgestein]]

== Herkunft ==
Gegenwärtig gibt es drei Quellen für Mondgestein auf der [[Erde]]:
# die durch die [[Vereinigte Staaten|amerikanischen]] [[Apollo-Programm|Apollo]]-Missionen gesammelten Gesteine,
# Proben, die von [[Sowjetunion|sowjetischen]] [[Luna-Programm|Luna]]-Missionen mitgebracht wurden, und
# Gesteine, die auf natürliche Weise durch [[Impakt]]e aus der Oberfläche des Mondes geschleudert wurden und als [[Meteorit]]e auf die Erde fielen.

[[Datei:Allan Hills 81005, lunar meteorite.jpg|miniatur|Der erste nachgewiesene [[Mondmeteorit]] Allan Hills 81005 aus der Antarktis.]]
Während der sechs Apollo-Exkursionen wurden 2415 Proben mit einem Gesamtgewicht von 382 kg gesammelt, das meiste davon durch [[Apollo 15]], [[Apollo 16|16]] und [[Apollo 17|17]]. Die drei Luna-Sonden brachten weitere 326 g Material zurück. Mehr als 90 [[Mondmeteoriten]] wurden bis 2006 auf der Erde gefunden, insgesamt mehr als 30 kg Material.

Im Apollo-Programm wurde Mondgestein mit einer Vielzahl von Werkzeugen gesammelt, einschließlich [[Hammer|Hämmern]], [[Rechen (Werkzeug)|Rechen]], [[Schaufel]]n, [[Zange]]n und [[Erdbohrer (Werkzeug)|Erdbohrern]]. Die meisten dieser Stücke wurden vor dem Einsammeln fotografiert, um ihren Fundzustand festzuhalten. Sie wurden in Tüten verpackt und dann in einem speziellen Behälter (''Special Environmental Sample Container'') beim Rückflug zur Erde aufbewahrt, um sie vor Kontaminationen zu schützen.

Etwas Mondstaub wurde angeblich auch von einem [[Hasselblad]]-Mitarbeiter gesammelt, der die von den Astronauten verwendeten Kameras nach den Apollo-Missionen reinigte.

{| border="1" cellspacing="0" cellpadding="4" align="right" style="clear: right"
!Mond-<br />Mission
!Mitgebrachte<br />Probenmengen
|-
|[[Apollo 11]]
|align="right"|22 kg
|-
|[[Apollo 12]]
|align="right"|34 kg
|-
|[[Apollo 14]]
|align="right"|43 kg
|-
|[[Apollo 15]]
|align="right"|77 kg
|-
|[[Apollo 16]]
|align="right"|95 kg
|-
|[[Apollo 17]]
|align="right"|111 kg
|-
|[[Luna 16]]
|align="right"|101 g
|-
|[[Luna 20]]
|align="right"|55 g
|-
|[[Luna 24]]
|align="right"|170 g
|}

== Eigenschaften ==
Insgesamt gesehen sind die auf dem Mond gesammelten Gesteine sehr alt im Vergleich zu Gesteinen, die auf der Erde gefunden werden, wie mit Hilfe von [[Radiometrische Datierung|radiometrischen Datierungsmethoden]] festgestellt werden konnte. Selbst das jüngste ist noch älter als alle auf der Erde vorkommenden Gesteine. Die Altersspanne reicht dabei von 3,2 Milliarden Jahren für die [[Basalt]]-Proben aus den [[Mare (Mond)|Maria]] bis zu 4,6 Milliarden Jahren in den [[Mond#Terrae|Terrae]], sie stellen daher Proben aus einer sehr frühen Periode des [[Sonnensystem]]s dar.

Die Gesteine verfügen über Charakteristika, die den Gesteinen auf der Erde sehr ähnlich sind, insbesondere was den Gehalt an [[Sauerstoff]]-[[Isotop]]en angeht. Allerdings findet man recht wenig [[Eisen]] in den Mondgesteinen, und sie sind auch arm an flüchtigen Elementen wie [[Kalium]] und [[Natrium]], Wasser fehlt gänzlich.

Im Mondgestein wurden drei neue [[Mineral]]e gefunden: [[Armalcolit]], [[Tranquillityit]] und [[Pyroxferroit]].

Die Altersbestimmung von etwa 50 [[Aufschmelzen| aufgeschmolzenen]] [[Gesteinsprobe]]n des Apollo-Programms 1969–1972 ergaben starke Hinweise auf eine Häufung großer Einschläge vor 4 bis 3,8 Milliarden Jahren („[[Großes Bombardement]]“), als deren Folge die meisten [[Mondmeer]]e entstanden.

== Wert ==
Mondgestein, das während der Erforschung des Mondes gesammelt wurde, wird gegenwärtig als unbezahlbar angesehen. 1993 wurden drei kleine, von Luna 16 mitgebrachte Fragmente, die 0,2 g wogen, für 442.500 Dollar verkauft. Im Jahr 2002 wurde ein Safe aus dem ''Lunar Sample Building'' gestohlen, der winzige Stücke Material vom Mond und Mars enthielt. Diese Stücke wurden wiedergefunden und 2003 von der [[NASA]] für das Gerichtsverfahren auf einen Wert von 1 Million Dollar für 285 g Material geschätzt. Mondgestein in Form von Meteoriten wird unter privaten Sammlern oft verkauft und getauscht, allerdings ebenfalls zu hohen Preisen.

== Aufbewahrung ==
[[Datei:Apollo 15 Genesis Rock.jpg|miniatur|[[Genesis Rock]], der von [[Apollo 15]] mitgebracht wurde.]]
[[Datei:Unnamed-Gilruth-S73-34103.jpg|miniatur|Untersuchung einer Mondgesteinsprobe von [[Apollo 17]].]]
[[Datei:Moon orange volcanic glass.jpg|miniatur|[[Orange Soil|Oranger Boden]], mitgebracht von Apollo 17.]]
Der Hauptaufbewahrungsort des Apollo-Mondgesteins ist das ''Lunar Sample Building'' am [[Lyndon B. Johnson Space Center]] in [[Houston]], [[Texas]]. Nach Aussagen der NASA werden fast 295 kg von ursprünglichen 382 kg der Proben noch immer unberührt dort aufbewahrt. Aus Sicherheitsgründen wird eine kleinere Sammlung auf der [[Brooks Air Force Base]] in [[San Antonio (Texas)|San Antonio, Texas]] aufbewahrt. Die meisten Steine werden in Stickstoff aufbewahrt, um sie vor Feuchtigkeit zu schützen. Sie werden nur indirekt mit Spezialwerkzeugen angefasst.

Nach der letzten Apollo-Mission ([[Apollo 17]]) wurden kleine Mondgestein-Proben in [[Acrylglas]] eingegossen. Zusammen mit der jeweiligen Nationalflagge, die von den Apollo-Astronauten zum Mond und wieder zurückgebracht wurde, wurden diese als „Goodwill Moon Rock“ bezeichneten Proben an 135 verschiedene Nationen verschenkt.<ref>[http://www.collectspace.com/resources/moonrocks_goodwill.html The history of the Goodwill moon rock]</ref>
Mindestens eines dieser Stücke wurde später gestohlen, verkauft und wiedergefunden.<ref>{{Webarchiv|url=http://www.space.com/news/honduras_moon_030923.html|wayback=20090513092443|text=Apollo Moon Rock Is Returned to Honduras}}</ref>
Einige kleine Stücke wurden auf Sockel montiert und an ehemalige Astronauten und andere verdiente Personen verschenkt.<ref>[http://www.collectspace.com/news/news-071404a.html NASA honoring astronauts, others with moon rocks]</ref><ref>[http://www.collectspace.com/news/news-041806a.html NASA gives Neil Armstrong a moon rock]</ref> Andere Proben wurden an ausgewählte Museen gegeben, z. B. das [[National Air and Space Museum]], das [[Kansas Cosmosphere and Space Center]], und das Besucherzentrum am [[Kennedy Space Center]]. Dort ist es möglich, „ein Stück Mond zu berühren“, es handelt sich allerdings in Wirklichkeit um ein kleines Stück Mondgestein, das in einem Pfeiler einzementiert ist, der in der Mitte eines für Besucher zugänglichen Tresorraums steht.

In Europa wurde Mondgestein erstmals 1970 im Schulungszentrum der [[Sternwarte Neanderhöhe Hochdahl]] ausgestellt.<ref>[http://snh.rp-online.de/schulungsz.shtml Erstmalige Ausstellung von Mondgestein in Deutschland]</ref> Heute ist Mondgestein im [[Deutsches Technikmuseum Berlin|Deutschen Technik Museum]] in [[Berlin]] (333 g, von Apollo 17), im [[Haus der Geschichte]] in [[Bonn]] (282 g, von [[Apollo 12]]), im [[Rieskrater-Museum]] in [[Nördlingen]] (163 g, von [[Apollo 16]]), im [[Technik-Museum_Speyer|Technik Museum]] in [[Speyer]] (177 g, von [[Apollo 15]]) und im [[Deutsches Museum|Deutschen Museum]] in [[München]] ausgestellt.<ref>{{Webarchiv|url=http://www.urbin.de/fakten/fa_086.htm|wayback=20070927013521|text=Wo kann man in Deutschland echtes Mondgestein sehen?}}</ref><ref>[[Frankfurt-Bockenheim#Museen|Wikipedia aaO]]</ref> In Österreich ist ein Stück Mondgestein im Meteoritensaal des [[Naturhistorisches Museum Wien|Naturhistorischen Museums]] in [[Wien]] zu sehen. Bei den beiden letztgenannten Proben handelt es sich um die oben erwähnten „Goodwill Moon Rocks“ von Deutschland und Österreich. Weiters ist eine 160 g schwere, von Apollo 15 aufgesammelte Probe in der Weltraumausstellung des [[Büro der Vereinten Nationen für Weltraumfragen|Büros für Weltraumfragen der UN]] in Wien zu sehen.<ref>[http://www.unis.unvienna.org/unis/pressrels/2002/os246.html Die Vereinten Nationen erhalten Mondgestein von den USA]</ref>

== Siehe auch ==
* [[Selenologie]]
* [[Mondmeteorit]]
* [[Astrogeologie]]
* [[Marsgestein]]
* [[Asteroidenbergbau]]
* [[KREEP]]

== Einzelnachweise ==
<references />

== Literatur ==
* Isidore Adler: ''The analysis of extraterrestrial materials.'' Wiley New York 1986 ISBN 0-471-87880-4.
* T. Kirsten: ''Isotopenanalysen an Mondproben.'' Naturwissenschaften, Volume 57, Number 5, Mai 1970 S.205-260 [http://www.springerlink.com/content/pp2058417l4lx105/fulltext.pdf?page=1 preview]

== Weblinks ==
{{Commonscat|Lunar samples|Mondgestein}}
* [http://www-curator.jsc.nasa.gov/lunar/index.cfm Rocks & Soils from the Moon] — Johnson Space Center
* [http://www.hq.nasa.gov/office/pao/History/alsj/tools/Welcome.html Apollo Geology Tool Catalog]
* [http://www.geotimes.org/sept02/NN_moon.html Moon rocks for sale!]
* [http://meteorites.wustl.edu/lunar/moon_meteorites.htm Lunar meteorites] — Washington University, Department of Earth and Planetary Sciences

{{Normdaten|TYP=s|GND=4170434-4}}

[[Kategorie:Apollo-Programm]]
[[Kategorie:Geologie des Erdmonds]]
[[Kategorie:Gestein]]

Belʹkovich

2014-08-02T12:59:40Z

Jstuby: replaced image of mare humboldtianum with one of Bekovich only

{{lunar crater data|
image=[[Image:Bel'kovich crater 4140 med.jpg|240px]]|
caption=Oblique [[Lunar Orbiter 4]] image|
latitude=61.1|
N_or_S=N|
longitude=90.2|
E_or_W=E|
diameter=214 km|
depth=''Unknown''|
colong=277|
eponym=[[Igor Vladimirovich Bel'kovich|Igor V. Bel'kovich]]}}
'''Bel'kovich''' is a large [[moon|lunar]] [[Impact crater|crater]] of the form termed a walled plain. The formation has been heavily eroded by a history of subsequent impacts, leaving it reshaped, worn, and the features softened and rounded. Bel'kovich is located along the northeastern limb of the [[Moon]], and so its visibility is subject to [[libration]] effects. From the [[Earth]] this crater is viewed from the side, making it difficult to view it in detail.

Bel'kovich intrudes into the northeast portion of the [[Mare Humboldtianum]], and the mare area outside the rim consists of hilly, irregular surface that covers much of the northern half of the [[lunar mare]]. The younger crater [[Hayn (crater)|Hayn]] intrudes into the northwest rim of Bel'kovich, and the satellite crater Bel'kovich K lies across the northeast rim. In the south, the [[lava]]-flooded crater Bel'kovich A cuts across the southern rim, and its western rim is overlain in turn by the small, bowl-shaped Bel'kovich B.

Apart from the intersecting crater formations, the outer rim of Bel'kovich has been degraded and reshaped until it now consists of a roughly circular range of mountains and hills. The northern and northeastern parts of the crater floor and rim is an irregular surface of many small hillocks. The southeast quadrant of the interior is nearly as irregular, and contains a number os small craterlets. Only in the western part of the floor is the surface relatively flat. From here a slender [[rille]] extends to the east-southeast before bending to the southeast.

==Satellite craters==
By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Bel'kovich.

{| class="wikitable"
!width="25%" style="background:#eeeeee;" |Bel'kovich
!width="25%" style="background:#eeeeee;" |Latitude
!width="25%" style="background:#eeeeee;" |Longitude
!width="25%" style="background:#eeeeee;" |Diameter
|-
|align="center"|A
|align="center"|58.7° N
|align="center"|86.0° E
|align="center"|58 km
|-
|align="center"|B
|align="center"|58.9° N
|align="center"|85.0° E
|align="center"|13 km
|-
|align="center"|K
|align="center"|63.8° N
|align="center"|93.6° E
|align="center"|47 km
|}

==References==
{{refbegin}}
* {{cite book
| last1 = Andersson
| first1 = L. E.
| last2 = Whitaker
| first2 = E. A.
| authorlink2 = Ewen Whitaker
| year = 1982
| title = [[NASA]] Catalogue of Lunar Nomenclature
| publisher = NASA RP-1097
| ref = harv
}}
* {{cite web
| last = Blue
| first = Jennifer
| date = July 25, 2007
| title = Gazetteer of Planetary Nomenclature
| publisher = [[United States Geological Survey|USGS]]
| url = http://planetarynames.wr.usgs.gov/
| accessdate = 2007-08-05
| ref = harv
}}
* {{cite book
| last1 = Bussey
| first1 = B.
| authorlink1 = Ben Bussey
| last2 = Spudis
| first2 = P.
| authorlink2 = Paul Spudis
| year = 2004
| title = The Clementine Atlas of the Moon
| publisher = Cambridge University Press
| location = New York
| isbn = 978-0-521-81528-4
| ref = harv
}}
* {{cite book
| last1 = Cocks
| first1 = Elijah E.
| last2 = Cocks
| first2 = Josiah C.
| year = 1995
| title = Who's Who on the Moon: A Biographical Dictionary of Lunar Nomenclature
| publisher = Tudor Publishers
| isbn = 978-0-936389-27-1
| ref = harv
}}
* {{cite web
| last = McDowell
| first = Jonathan
| date = July 15, 2007
| url = http://host.planet4589.org/astro/lunar/
| title = Lunar Nomenclature
| publisher = Jonathan's Space Report
| accessdate = 2007-10-24
| ref = harv
}}
* {{cite doi | 10.1007/BF00171763 }}
* {{cite book
| first = Patrick
| last = Moore
| authorlink = Patrick Moore
| year = 2001
| title = On the Moon
| publisher = Sterling Publishing Co
| isbn = 978-0-304-35469-6
| ref = harv
}}
* {{cite book
| first = Fred W.
| last = Price
| year = 1988
| title = The Moon Observer's Handbook
| publisher = Cambridge University Press
| isbn = 978-0-521-33500-3
| ref = harv
}}
* {{cite book
| last = Rükl
| first = Antonín
| authorlink = Antonín Rükl
| year = 1990
| title = Atlas of the Moon
| publisher = Kalmbach Books
| isbn = 978-0-913135-17-4
| ref = harv
}}
* {{cite book
| last = Webb
| first = Rev. T. W.
| authorlink = Thomas William Webb
| year = 1962
| title = Celestial Objects for Common Telescopes
| edition = 6th revision
| publisher = Dover
| isbn = 978-0-486-20917-3
| ref = harv
}}
* {{cite book
| first = Ewen A.
| last = Whitaker
| authorlink = Ewen Whitaker
| year = 1999
| title = Mapping and Naming the Moon
| publisher = Cambridge University Press
| isbn = 978-0-521-62248-6
| ref = harv
}}
* {{cite book
| first = Peter T.
| last = Wlasuk
| year = 2000
| title = Observing the Moon
| publisher = Springer
| isbn = 978-1-85233-193-1
| ref = harv
}}
{{refend}}

{{DEFAULTSORT:Belkovich}}
[[Category:Impact craters on the Moon]]

Key Largo Dry Rocks

2011-02-20T04:23:34Z

Jstuby: Christ of the Abyss

'''Dry Rocks''' (or Key Largo Dry Rocks) is a [[coral reef]] located within the [[Florida Keys National Marine Sanctuary]]. It lies to the east of [[Key Largo]], within the Key Largo Existing Management Area, which is immediately to the east of [[John Pennekamp Coral Reef State Park]]. The reef lies within a Sanctuary Preservation Area (SPA). It is close to [[Grecian Rocks (reef)|Grecian Rocks]] and [[The Elbow (reef)|The Elbow]].

The famous [[Christ of the Abyss]] statue is located at this reef.

This reef is distinct from White Banks Dry Rocks, which is landward of [[Molasses Reef]] and [[French Reef]].

Approximate coordinates: {{Coord|25|07|20|N|80|18|00|W|source:NOAA_region:US-FL|display=inline,title}}

==External Links==
* [http://flkeysbenthicmaps.noaa.gov/data/pro_areas_htmls/dry_rocks.html Benthic Habitat Map]

==References==
* [http://sanctuaries.noaa.gov/pgallery/atlasmaps/images/fkeast_2000.jpg NOAA National Marine Sanctuary Maps, Florida Keys East]
* [http://www.charts.noaa.gov/OnLineViewer/11464.shtml NOAA Navigational Chart 11464]

{{corals}}

[[Category:Marine biology]]
[[Category:Reefs of the Atlantic Ocean]]

Key Largo Dry Rocks

2011-01-18T00:45:13Z

Jstuby: added external links, and link to benthic habitat map

'''Dry Rocks''' (or Key Largo Dry Rocks) is a [[coral reef]] located within the [[Florida Keys National Marine Sanctuary]]. It lies to the east of [[Key Largo]], within the Key Largo Existing Management Area, which is immediately to the east of [[John Pennekamp Coral Reef State Park]]. The reef lies within a Sanctuary Preservation Area (SPA). It is close to [[Grecian Rocks (reef)|Grecian Rocks]] and [[The Elbow (reef)|The Elbow]].

This reef is distinct from White Banks Dry Rocks, which is landward of [[Molasses Reef]] and [[French Reef]].

Approximate coordinates: {{Coord|25|07|20|N|80|18|00|W|source:NOAA_region:US-FL|display=inline,title}}

==External Links==
* [http://flkeysbenthicmaps.noaa.gov/data/pro_areas_htmls/dry_rocks.html Benthic Habitat Map]

==References==
* [http://sanctuaries.noaa.gov/pgallery/atlasmaps/images/fkeast_2000.jpg NOAA National Marine Sanctuary Maps, Florida Keys East]
* [http://www.charts.noaa.gov/OnLineViewer/11464.shtml NOAA Navigational Chart 11464]

{{corals}}

[[Category:Marine biology]]
[[Category:Reefs of the Atlantic Ocean]]

Florida Reef

2011-01-04T03:02:06Z

Jstuby: /* Reef structure and communities */

The '''Florida Reef''' (also known as the '''Great Florida Reef''', '''Florida reefs''', '''Florida Reef Tract''' and '''Florida Keys Reef Tract''') is the only living [[Coral reef|coral barrier reef]] in the continental United States. It is the third largest coral barrier reef system in the world (after the [[Great Barrier Reef]] and [[Belize Barrier Reef]]).<ref>[http://coris.noaa.gov/portals/florida.html ''Florida'' NOAA's Coral Reef Information System] Accessed December 14, 2010</ref> It lies a few miles seaward of the [[Florida Keys]], is about 4 miles (6 to 7 km) wide and extends (along the 20 meter depth contour) 270 km (145 miles) from [[Fowey Rocks Light|Fowey Rocks]] just east of [[Soldier Key]] to just south of the [[Marquesas Keys]]. The barrier reef tract forms a great arc, concentric with the Florida Keys, with the northern end, in [[Biscayne National Park]], oriented north-south and the western end, south of the Marquesas Keys, oriented east-west. The rest of the reef outside Biscayne National Park lies within [[John Pennekamp Coral Reef State Park]] and the [[Florida Keys National Marine Sanctuary]]. Isolated coral patch reefs occur northward from Biscayne National Park as far as [[Stuart, Florida|Stuart]], in [[Martin County, Florida|Martin County]]. Coral reefs are also found in [[Dry Tortugas National Park]] west of the Marquesas Keys. There are more than 6,000 individual reefs in the system. The reefs are 5,000 to 7,000 years old, having developed since sea levels rose following the [[Wisconsinan glaciation]].<ref>[http://www.dep.state.fl.us/coastal/habitats/coral.htm ''Florida's Coral Reefs'' Florida Department of Environmental Protection] Accessed December 14, 2010.<br>[http://www.flmnh.ufl.edu/fish/southflorida/coral/conservation.html ''Florida Keys Conservation: National Marine Sanctuary'' Ichthyology at the Florida Museum of Natural History] Accessed December 14, 2010<br>Precht and Miller:243<br>Marszalek et alia:224</ref>

The densest and most spectacular reefs are found to the seaward of [[Key Largo]] (in and beyond John Pennekamp Coral Reef State Park) and [[Elliott Key]] where the two long keys help protect the reefs from the effects of water exchange with [[Florida Bay]], [[Biscayne Bay]], [[Card Sound]] and [[Barnes Sound]]. The bays and sounds (all between the Florida Keys and the mainland) tend to have lower [[salinity]], higher [[turbidity]] and wider temperature variations than the water in the open ocean. Channels between the Keys allow water from the bays to flow onto the reefs (especially in the middle Keys), limiting their growth.<ref>[http://sofia.usgs.gov/publications/circular/1134/esns/frt.html U.S. Geological Survey Circular 1134 - Florida Reef Tract] Accessed December 16, 2010<br>Precht and Miller:243<br>Marszalek et alia:228</ref>

==Reef structure and communities==
The Florida Reef consists of two ridges separated from the Florida Keys by the Hawk Channel. Closest to the Keys is a sand ridge called ''White Bank'', covered by large beds of sea grass, with patch reefs scattered across it. Further out to sea on the edge of the [[Florida Straits]] is the second ridge forming the outer reefs, covered by reefs and hard banks composed of coral rubble and sand.<ref>[http://sofia.usgs.gov/publications/circular/1134/esns/frt.html U.S. Geological Survey Circular 1134 - Florida Reef Tract] Accessed December 16, 2010</ref>

Almost 1,400 species of marine plants and animals, including more than 40 species of [[stony coral]]s and 500 species of fish, live on the Florida Reef. The Florida Reef lies close to the northern limit for tropical corals, but the species diversity on the reef is comparable to that of reef systems in the [[Caribbean Sea]].<ref>[http://sofia.usgs.gov/publications/circular/1134/esns/frt.html U.S. Geological Survey Circular 1134 - Florida Reef Tract] Accessed December 16, 2010</ref>

The [[Florida Museum of Natural History]] defines three communities on the Florida reefs. The ''hardbottom'' community lies closest to the Florida Keys and consists primarily of [[algae]], sea fans ([[gorgonian]]s) and stony corals growing on [[limestone]] rock that has a thin covering of sand. The stony corals in hardbottom communities include Smooth Starlet coral (''Siderastrea radians''), Mustard Hill Coral (''[[Porites astreoides]]''), Golfball coral (''Favia fragum''), Elliptical Star coral (''Dichocoenia stokesii'') and Common [[Brain coral]] (''Diploria strigosa''). Hardbottom provides habitat for [[anemone]]s, [[mollusk]]s, [[crab]]s, [[spiny lobster]]s, [[seastar]]s, [[sea cucumber]]s, [[tunicate]]s and various fish, including [[grunt]]s (''Haemulon'' spp.), [[snapper]]s (''Lutjanus'' spp.), [[grouper]]s (''Epinephelus'' spp.), [[tang]]s (''Acanthurus coeruleus''), [[Ocean surgeon]] (''Acanthurus bahianus'') and [[Great barracuda]] (''Spyraena barracuda'').<ref>[http://www.flmnh.ufl.edu/fish/southflorida/coral/Communities.html ''Hardbottom Community'' Ichthyology at the Florida Museum of Natural History] Accessed December 15, 2010</ref>

Second is the ''patch reef'' community. Patch reefs form in shallow water (three to six meters deep), some in Hawk Channel and some on the outer reef, but mainly on White Bank between Hawk Channel and the outer reefs. Patch reefs start from corals growing on a hard bottom, but grow upward as new corals establish themselves on the skeletons of dead corals. Most of the structure of patch reefs is formed from star (''[[Montastraea annularis]]'', ''Siderastrea siderea'') and [[brain coral|brain]] corals (''Diploria'' spp.). Other corals attach wherever there is an opening. Patch reefs may grow up to the surface of the water, and spread outwards. ''Dome''-type patch reefs (such as [[Hen and Chickens (reef)|Hen and Chickens]]), found in Hawk Channel and on White Bank, are round or elliptical, and are generally less than three meters high, but may reach up to nine meters high. Dome-type patch reefs are surrounded by sand which is kept clear due to browsing by [[Diadema antillarum|long-spined sea urchins]] and grass-eating fish. ''Linear''-type patch reefs are found on the outer reefs, and are linear or curved. They occur in single or multiple rows, trending the same direction as the bank reefs on the outer reefs. Linear-type patch reefs often include [[Elkhorn coral]], which is rare on the dome-type patch reefs. As dead coral skeletons age and are weakened by the activities of boring [[sponges]], [[Marine worm|worms]], and [[mollusks]] and by wave action, parts of a patch reef may collapse. Patch reefs provide habitat for spiny lobsters and for many species of fish, including Bluehead wrasse (''[[Thalassoma bifasciatum]]''), [[damselfish]] (''Chromis'' spp.), Ocean surgeon, [[French angelfish|French]] and [[Queen angelfish|Queen]] angelfish (''Pomacanthus'' spp.), White, Caesar and Spanish grunts (''Haemulon'' ssp.), [[Yellowtail snapper|Yellowtail]] and other snappers, Redband and Stoplight [[parrotfish]] (''Sparisoma'' ssp.), [[Sergeant major (fish)|Sergeant major]] (''Abudefduf saxatilis''), Tomtate (''Haemulon aurolineatum''), [[Trumpetfish]] (''Aulostomus maculatus''), [[filefish]], groupers, snappers, [[Bar jack]] (''Caranx ruber''), Great barracuda, [[pufferfish]], [[squirrelfish]], [[cardinalfish]], and [[green moray]]s (''Gymnothorax funebris'').<ref>[http://www.flmnh.ufl.edu/fish/southflorida/coral/patchreef.html#patch ''Patch Reef Community'' Ichthyology at the Florida Museum of Natural History] Accessed December 15, 2010<br>Marszalek et alia:224, 227</ref>

Third is the ''bank reef'' community. Bank reefs are larger than patch reefs and are found on the outer reefs. Bank reefs consist of three zones. The ''reef flat'' is closest to the keys, and consists of [[coralline algae]] growing on fragments of coral skeletons. Further out to sea are the ''spur and groove formations'', low ridges of coral (the spurs) separated by channels with sand bottoms (the grooves). The shallowest parts of the spurs support [[fire coral]]s and [[Zoantharia|zoanthids]]. Starting at five or six feet deep, Elkhorn, star, and brain corals are the most important members of the community. Various types of gorgonians are also common. Beyond the spur and groove zone is the ''forereef'', which slopes down to the deeps. The upper forereef is dominated by star coral. At greater depths plate-like corals dominate, and then as the available light fades, sponges and non-reef building corals become common. Bank reefs provide habitat for various fishes, including French angelfish, Blue and Queen [[parrotfish]], [[Queen triggerfish]] (''Balistes vetula''), [[Rock beauty|Rock beauties]] (''Holacanthus tricolor''), [[Goatfish]] (''Parupeneus cyclostomus''), Porkfish (''[[Anisotremus virginicus]]'') and snappers. The sand found around and in the Florida Reef is composed of shell, coral skeleton and limestone fragments.<ref>[http://www.flmnh.ufl.edu/fish/southflorida/coral/Bankreef.html ''Bank Reef Community'' Ichthyology at the Florida Museum of Natural History] Accessed December 15, 2010</ref>

Other common species of hard coral found on the Florida Reef include [[Ivory Bush Coral]] (''Oculina diffusa''), which is the dominant coral in the patch reefs along the Florida coast north of the Florida Keys, [[Staghorn coral]] (''Acropora cervicornis''), Lettuce Coral (''Agaricia agaricites''), Grooved Brain Coral (''Diploria labrynthiformis''), Boulder Star Coral (''Monstastrea annularis''), Great Star Coral (''M. cavernosa''), Clubbed Finger Coral (''[[Porites]] porites'') and Massive Starlet Coral (''Siderastrea siderea'').<ref>[http://www.flmnh.ufl.edu/fish/southflorida/coral/Profiles.html ''Common Corals of Florida'' Ichthyology at the Florida Museum of Natural History] Accessed December 15, 2010<br>[http://www.flmnh.ufl.edu/fish/southflorida/coral/Distribution.html ''Coral Reefs Geographical Distribution'' Ichthyology at the Florida Museum of Natural History] Accessed December 15, 2010</ref>

==Threats to the reefs==
{{Also|Environmental issues with coral reefs|Coral reef protection}}
In common with coral reefs throughout the Caribbean and the world, the Florida Reef exhibits signs of stress and deterioration. Precht and Miller state that the numbers of Elkhorn and Staghorn corals (''[[Acropora]]'' ssp.) are declining to an extent that is unprecedented in several thousand years. Between 1981 and 1986, Staghorn corals declined by 96% at [[Molasses Reef]]. Between 1983 and 2000 at [[Looe Key]], Elkhorn corals declined by 93% and Staghorn corals by 98%. A joint reef monitoring program conducted by the [[United States Environmental Protection Agency]], Florida Marine Research Institute and [[National Oceanic and Atmospheric Administration]] recorded a loss of 6% to 10% living corals at 40 sampling stations from 1996 to 2000.<ref>Precht and Miller:241, 246, 267</ref>

Prolonged cold weather over southern Florida can lower sea water temperature enough to kill corals (Staghorn coral is killed by a water temperature of 13.5° C). The movement of cold fronts over Florida Bay and the Florida Keys have resulted in large kill offs of Elkhorn and Staghorn corals in the middle Keys and in the Dry Tortugas. Elevated temperatures also are damaging to coral reefs, causing [[coral bleaching]]. The first recorded bleaching incident on the Florida Reef was in 1973. Incidents of bleaching have become more frequent in recent decades, in correlation with a rise in [[sea surface temperature]]s. [[White band disease]] has also adversely affected corals on the Florida Reef. While hurricanes often can cause localized damage to Elkhorn and Staghorn corals, Precht and Miller state that the severe and widespread loss of those corals on the Florida Reef cannot be attributed to hurricane damage. Other possible causes of the losses of corals on the Florida Reef include [[epizootic]] diseases, [[eutrophication]], [[predation]], [[sedimentation]], [[overfishing]], [[ship grounding]]s, anchor dragging, commercial lobster and crab traps moved by storms, pollution, development on the Keys, growing numbers of visitors to the Keys and the reefs and the growth of seaweed on the coral.<ref>Precht and Miller:243-44, 245, 247-48, 249<br>[http://serc.fiu.edu/wqmnetwork/boyerj/pubs/NOAA%20Coral%20Florida%20Keys2008.pdf The State of Coral Reef Ecosystems of the Florida Keys] Accessed December 17, 2010</ref>

The long-spined sea urchin (''Diadema antillarum''), which browses on seaweed on and around reefs, was sharply reduced in numbers on the Florida Reef (and throughout the Caribbean) in the 1980s. While populations of this sea urchin have somewhat recovered elsewhere, its numbers are still very low on most of the Florida Reef, with the exception of the Dry Tortugas. As a consequence, there has been no effective check of the growth of seaweed on reef corals. However, the severe die-off of Elkhorn and Staghorn corals occurred before the die-off of the sea urchins, so that the proliferation of seaweed following the loss of the sea urchins was not the cause of the die-off of the corals, but may be retarding recovery by the corals.<ref>[http://faculty.mdc.edu/mchiappo/publications/diadema_urchin_paper_coral_reefs.pdf Large-scale surveys on the Florida Reef Tract indicate poor recovery of the long-spined sea urchin ''Diadema antillarum''] Accessed December 17, 2010<br>Precht and Miller:249<br>[http://serc.fiu.edu/wqmnetwork/boyerj/pubs/NOAA%20Coral%20Florida%20Keys2008.pdf The State of Coral Reef Ecosystems of the Florida Keys] Accessed December 17, 2010</ref>

Another threat to the Florida Reef is the ongoing [[Current sea level rise|rise in sea level]]. The sea level has risen almost six inches (15 cm) at [[Key West, Florida|Key West]] since 1913, and one foot (30 cm) since 1850. This rise in sea level increases the volume of water in Florida Bay significantly, and increases the exchange of water between the Bay and the water over the reefs. The lower salinity, higher turbidity and more variable temperature of the water from Florida Bay adversely affects the reefs. A continued rise in sea level would likely intensify the effect.<ref>[http://sofia.usgs.gov/publications/circular/1134/esns/cfsl.html U.S. Geological Survey Circular 1134 - Coral Reefs and Sea Level] Accessed December 16, 2010</ref>

A perceived deterioration of the reefs became a concern in the 1950s. Early attempts to protect the reefs led to the establishment in 1960 of a protected area that became John Pennekamp Coral Reef State Park. The creation of Biscayne National Monument (which later became Biscayne National Park) in 1968 protected the northern part of the Florida Reef. In 1990 the Florida Keys National Marine Sanctuary was established, bringing all of the Florida reef into federal or state protection.<ref>Precht and Miller:266</ref>

==Human use==

Human use of the reefs has grown tremendously in the past century. One measure of the growth is that registrations for recreational boats in Monroe County increased by 1000% from 1964 to 2006.<ref>[http://serc.fiu.edu/wqmnetwork/boyerj/pubs/NOAA%20Coral%20Florida%20Keys2008.pdf The State of Coral Reef Ecosystems of the Florida Keys] Accessed December 17, 2010</ref>

Recreational use of the Florida Reef and surrounding waters is popular and important to the economy of southern Florida, and in particular, of Monroe County. In 2000-2001 artificial and natural reefs in [[South Florida]] and Monroe County had 28 million person-days of recreational use by residents and tourists, including [[scuba diving]], fishing and viewing (as, for example, by [[snorkeling]]). These activities generated $4.4 million in sales, generated almost $2 million in local income and provided more than 70,000 full- and part-time jobs. The estimated asset value of the reefs was $8.5 billion. About two-thirds of the activity was related to natural reefs.<ref>[http://coralreef.noaa.gov/aboutcorals/values/tourismrecreation/ NOAA Coral Reef Conservation Program - Tourism and Recreation] Accessed December 17, 2010</ref>

In Monroe County for the period of June 2000 to May 2001 almost 5.5 million person-days of reef related activities resulted in $504 million in sales, which generated $140 million in income for 10,000 full- and part-time jobs. Almost two-thirds of the activity was by residents, and about half the activity involved fishing, with one-third involving snorkeling and one-sixth scuba diving.
<ref>[http://sanctuaries.noaa.gov/science/socioeconomic/floridakeys/pdfs/monroefact.pdf Socioeconomic Study of Reefs in Southeast Florida - Monroe County] Accessed December 17, 2010</ref>

In Miami-Dade County for the period from June 2000 to May 2001 a little over 6 million person-days of reef related activities resulted in $1,297 million in sales, which generated $614 million in income for 19,000 full- and part-time jobs. The activity was about evenly split between residents and tourists. As in Monroe County, about half the activity involved fishing, with one-third involving snorkeling and one-sixth scuba diving.<ref>[http://sanctuaries.noaa.gov/science/socioeconomic/floridakeys/pdfs/miamidadefact.pdf Socioeconomic Study of Reefs in Southeast Florida - Miami-Dade County] Accessed December 17, 2010</ref>

==Shipwrecks and lighthouses==

The [[Florida Current]] (which merges with the [[Antilles Current]] near the northern end of the barrier reef to form the [[Gulf Stream]]) passes close to the Florida Reef through the [[Straits of Florida]]. Ships began wrecking along the Florida Reef almost as soon as Europeans reached the [[New World]]. From early in the 16th century Spanish ships returning from the New World to Spain sailed from [[Havana]] to catch the Gulf Stream, which meant they passed close to the Florida Reef, with some wrecking on the reefs. In 1622, six ships of the [[Spanish treasure fleet]], including the ''[[Nuestra Señora de Atocha]]'', wrecked during a [[Tropical cyclone|hurricane]] in the lower Keys. In 1733, 19 ships of the Spanish treasure fleet wrecked during a hurricane in the middle and upper keys. In the 19th century the Straits became the major route for shipping between the eastern coast of the [[United States]] and ports in the [[Gulf of Mexico]] and the western [[Caribbean Sea]]. The combination of heavy shipping and a powerful current flowing close to dangerous reefs made the Florida Reef the site of many wrecks. By the middle of the 19th century ships were wrecking on the Florida Reef at the rate of almost once a week (the collector of customs in Key West reported a rate of 48 wrecks a year in 1848).<ref>Viele. Pp. 54-5</ref> Between 1848 and 1859 at least 618 ships were wrecked on the Florida Reef.<ref>Langley and Parks:5</ref> The Assistant United States Coast Surveyor reported that in the period from 1845 through 1849 almost one million (United States) dollars worth of vessels and cargos were lost on the reef.<ref>Blank:63</ref> The chief motivation for the [[Florida Railroad]], the first railroad to connect the Atlantic and Gulf coasts of Florida, was to allow goods to be transferred between ships in the Atlantic and in the Gulf of Mexico, thus avoiding the dangerous passage along the Florida Reef. [[Wrecking (shipwreck)#Wrecking in the Florida Keys|Salvaging wrecks on the reefs]] was the principal occupation in the Florida Keys through much of the 19th century, helping make Key West the biggest and richest city in Florida for a while.<ref>Viele 2001:3-14, 54-5, 166<br>Turner:27-8<br>Burnett:105<br>[http://www.monroecounty-fl.gov/pages/MonroeCoFL_Admin/about Facts about Monroe County] Accessed December 17, 2010</ref>

Some of the reefs in the Florida Reef are named after ships that wrecked on them. Fowey Rocks is named after [[HMS Fowey (1744)|HMS ''Fowey'']], which, however, actually wrecked on Ajax Reef. Looe Key is named after [[HMS Looe (1741)|HMS ''Looe'']]. [[Alligator Reef]] is named after the [[USS Alligator (1820)|USS ''Alligator'']].<ref>Viele 1999:26-31, 92-94</ref> [[Carysfort (reef)|Carysfort Reef]] is named after [[HMS Carysfort (1766)|HMS ''Carysfort'']], which ran aground on the reef, but did not sink.<ref>{{cite uscghist|FL}}</ref>

Soon after the United States acquired Florida from Spain in 1821, it began building [[lighthouse]]s along the Florida coast. The first lighthouses marking the Florida Reef were the [[Cape Florida Light]], at the northern end of the Reef, the [[Dry Tortugas Light]] (on Bush Key), marking the western end of the Reef, and the [[Key West Light]], all first lit in 1825. A [[light ship]] was placed at [[Carysfort Reef Light|Carysfort Reef]] in 1825, as well. [[Garden Key Light]], also in the Dry Tortugas, was added in 1826, and [[Sand Key Light]] (six nautical miles from [[Key West, Florida|Key West]]), was added in 1827. Large stretches of the Florida Reef remained unprotected by lighthouses, however. Keeping lights in operation along the Florida Reef proved difficult. The Carysfort Reef light ship was often blown out of position, and one time even onto a reef. The first light ship had to be replaced after just five years due to dry rot. The Cape Florida lighthouse was burned by [[Seminoles]] in 1836, and was not repaired and re-lit until 1847. The Key West and Sand Key lighthouses were destroyed by a hurricane in 1846. Starting at Carysfort Reef in 1852, [[skeletal tower]] lighthouses were built on submerged reefs to place lights as close to the outer edge of the Florida Reef as possible. With the completion of the [[American Shoal Light]] in 1880 there were finally navigation lights visible along the full length of the Florida Reef.<ref>Viele 2001:140, 154-59<br>[http://www.uscg.mil/history/weblighthouses/LHFL.asp United States Coast Guard Historic Light Station Information & Photography - Florida - American Shoal Light] Accessed December 16, 2010</ref>

In order to provide better charts for ships sailing along the Florida Reef, the Florida Keys, including the reef, and the waters to the west of the Keys, including Biscayne Bay and Florida Bay, were surveyed in the 1850s. The [[United States Army Corps of Engineers|United States Army Corps of Topographical Engineers]] established a base camp on Key Biscayne in 1849. The [[triangulation]] survey was conducted by the [[U.S. National Geodetic Survey|U.S. Coast Survey]] with men detailed from the U.S. Army and U.S. Navy. In 1855 [[Alexander Dallas Bache]], Superintendent of the U.S. Coast Survey, assumed personal direction of the survey. In 1851 [[Louis Agassiz]] was sent by the U.S. Coast Survey to study the Florida Reef.<ref>Blank:61-66</ref> His report on the reefs was published in 1880.<ref>[http://books.google.com/books?id=rroQAAAAIAAJ&printsec=frontcover&dq=%22Report+on+the+Florida+Reefs%22&source=bl&ots=GyFJ1GPgwb&sig=70-IAJtpXPkf3t2JPPkdHsTwXHU&hl=en&ei=jnMHTYvCE4H58AaioKjWCg&sa=X&oi=book_result&ct=result&resnum=1&sqi=2&ved=0CBkQ6AEwAA#v=onepage&q&f=false Agassiz, Louis. (1880) "Report on the Florida reefs." ''Memoirs of the Museum of Comparative Zoology'' VII:1. Harvard College.] Accessed December 14, 2010</ref>

==Notes==
{{reflist|3}}

==References==
*Blank, Joan Gill. (1996) ''Key Biscayne.'' Sarasota, Florida: Pineapple Press, Inc. ISBN 1-56164-096-4
*Burnett, Gene. (1991) ''Florida's Past: People and Events That Shaped the State. Volume 3.'' Sarasota, Florida: Pineapple Press. ISBN 1-56164-117-0 Found at [http://books.google.com/ Google books] Accessed December 17, 2010
*Langley, Wright and Arva Moore Parks (editors). (1983) "Diary of an Unidentified Land Official, 1855: Key West to Miami." ''Tequesta: The Journal of the Historical Association of Southern Florida.'' Number XLIII. Found at [http://ufdc.ufl.edu/UF00101446/00043/5j] Accessed December 19, 2010
*Marszalek, D. S., G. Babashoff, Jr., M. R. Noel and D. R. Worley. (1977) "Reef Distribution in South Florida." ''Proceedings, Third International Coral Reef Symposium.'' Rosenstiel School of Marine and Atmospheric Science, University of Miami. Found at [http://www.nova.edu/ocean/feingold/marszalek.pdf] Accessed December 18, 2010
*Precht, W. F. and S. L. Miller. (2007) "Ecological Shifts along the Florida Reef Tract: The Past as a Key to the Future." In R. B. Aronson. (Editor) ''Geological Approaches to Coral Reef Ecology.'' Found at [http://people.uncw.edu/millers/documents/Precht%20and%20Miller%20Ch.pdf] Accessed December 16, 2010
*Turner, Gregg. (2003) ''A Short History of Florida Railroads.'' Charleston, South Carolina: Arcadia Publishing. ISBN 0-7385-2421-2
*Viele, John. (1999) ''The Florida Keys: True Tales of the Perilous Straits.'' Sarasota, Florida: Pineapple Press, Inc. ISBN 1-56164-179-0
*Viele, John. (2001) ''The Florida Keys: The Wreckers.'' Sarasota, Florida: Pineapple Press, Inc. ISBN 1-56164-219-3

==External links==
*[http://www.eoearth.org/article/Coral_reefs_in_Florida "Coral reefs in Florida." The Encyclopedia of Earth]

{{Florida Keys}}

[[Category:Florida Keys]]
[[Category:Coral reefs of Florida]]

Florida Reef

2011-01-04T02:59:41Z

Jstuby: /* Shipwrecks and lighthouses */

The '''Florida Reef''' (also known as the '''Great Florida Reef''', '''Florida reefs''', '''Florida Reef Tract''' and '''Florida Keys Reef Tract''') is the only living [[Coral reef|coral barrier reef]] in the continental United States. It is the third largest coral barrier reef system in the world (after the [[Great Barrier Reef]] and [[Belize Barrier Reef]]).<ref>[http://coris.noaa.gov/portals/florida.html ''Florida'' NOAA's Coral Reef Information System] Accessed December 14, 2010</ref> It lies a few miles seaward of the [[Florida Keys]], is about 4 miles (6 to 7 km) wide and extends (along the 20 meter depth contour) 270 km (145 miles) from [[Fowey Rocks Light|Fowey Rocks]] just east of [[Soldier Key]] to just south of the [[Marquesas Keys]]. The barrier reef tract forms a great arc, concentric with the Florida Keys, with the northern end, in [[Biscayne National Park]], oriented north-south and the western end, south of the Marquesas Keys, oriented east-west. The rest of the reef outside Biscayne National Park lies within [[John Pennekamp Coral Reef State Park]] and the [[Florida Keys National Marine Sanctuary]]. Isolated coral patch reefs occur northward from Biscayne National Park as far as [[Stuart, Florida|Stuart]], in [[Martin County, Florida|Martin County]]. Coral reefs are also found in [[Dry Tortugas National Park]] west of the Marquesas Keys. There are more than 6,000 individual reefs in the system. The reefs are 5,000 to 7,000 years old, having developed since sea levels rose following the [[Wisconsinan glaciation]].<ref>[http://www.dep.state.fl.us/coastal/habitats/coral.htm ''Florida's Coral Reefs'' Florida Department of Environmental Protection] Accessed December 14, 2010.<br>[http://www.flmnh.ufl.edu/fish/southflorida/coral/conservation.html ''Florida Keys Conservation: National Marine Sanctuary'' Ichthyology at the Florida Museum of Natural History] Accessed December 14, 2010<br>Precht and Miller:243<br>Marszalek et alia:224</ref>

The densest and most spectacular reefs are found to the seaward of [[Key Largo]] (in and beyond John Pennekamp Coral Reef State Park) and [[Elliott Key]] where the two long keys help protect the reefs from the effects of water exchange with [[Florida Bay]], [[Biscayne Bay]], [[Card Sound]] and [[Barnes Sound]]. The bays and sounds (all between the Florida Keys and the mainland) tend to have lower [[salinity]], higher [[turbidity]] and wider temperature variations than the water in the open ocean. Channels between the Keys allow water from the bays to flow onto the reefs (especially in the middle Keys), limiting their growth.<ref>[http://sofia.usgs.gov/publications/circular/1134/esns/frt.html U.S. Geological Survey Circular 1134 - Florida Reef Tract] Accessed December 16, 2010<br>Precht and Miller:243<br>Marszalek et alia:228</ref>

==Reef structure and communities==
The Florida Reef consists of two ridges separated from the Florida Keys by the Hawk Channel. Closest to the Keys is a sand ridge called ''White Bank'', covered by large beds of sea grass, with patch reefs scattered across it. Further out to sea on the edge of the [[Florida Straits]] is the second ridge forming the outer reefs, covered by reefs and hard banks composed of coral rubble and sand.<ref>[http://sofia.usgs.gov/publications/circular/1134/esns/frt.html U.S. Geological Survey Circular 1134 - Florida Reef Tract] Accessed December 16, 2010</ref>

Almost 1,400 species of marine plants and animals, including more than 40 species of [[stony coral]]s and 500 species of fish, live on the Florida Reef. The Florida Reef lies close to the northern limit for tropical corals, but the species diversity on the reef is comparable to that of reef systems in the [[Caribbean Sea]].<ref>[http://sofia.usgs.gov/publications/circular/1134/esns/frt.html U.S. Geological Survey Circular 1134 - Florida Reef Tract] Accessed December 16, 2010</ref>

The [[Florida Museum of Natural History]] defines three communities on the Florida reefs. The ''hardbottom'' community lies closest to the Florida Keys and consists primarily of [[algae]], sea fans ([[gorgonian]]s) and stony corals growing on [[limestone]] rock that has a thin covering of sand. The stony corals in hardbottom communities include Smooth Starlet coral (''Siderastrea radians''), Mustard Hill Coral (''[[Porites astreoides]]''), Golfball coral (''Favia fragum''), Elliptical Star coral (''Dichocoenia stokesii'') and Common [[Brain coral]] (''Diploria strigosa''). Hardbottom provides habitat for [[anemone]]s, [[mollusk]]s, [[crab]]s, [[spiny lobster]]s, [[seastar]]s, [[sea cucumber]]s, [[tunicate]]s and various fish, including [[grunt]]s (''Haemulon'' spp.), [[snapper]]s (''Lutjanus'' spp.), [[grouper]]s (''Epinephelus'' spp.), [[tang]]s (''Acanthurus coeruleus''), [[Ocean surgeon]] (''Acanthurus bahianus'') and [[Great barracuda]] (''Spyraena barracuda'').<ref>[http://www.flmnh.ufl.edu/fish/southflorida/coral/Communities.html ''Hardbottom Community'' Ichthyology at the Florida Museum of Natural History] Accessed December 15, 2010</ref>

Second is the ''patch reef'' community. Patch reefs form in shallow water (three to six meters deep), some in Hawk Channel and some on the outer reef, but mainly on White Bank between Hawk Channel and the outer reefs. Patch reefs start from corals growing on a hard bottom, but grow upward as new corals establish themselves on the skeletons of dead corals. Most of the structure of patch reefs is formed from star (''[[Montastraea annularis]]'', ''Siderastrea siderea'') and [[brain coral|brain]] corals (''Diploria'' spp.). Other corals attach wherever there is an opening. Patch reefs may grow up to the surface of the water, and spread outwards. ''Dome''-type patch reefs (such as [[Hen and Chickens Reef]]), found in Hawk Channel and on White Bank, are round or elliptical, and are generally less than three meters high, but may reach up to nine meters high. Dome-type patch reefs are surrounded by sand which is kept clear due to browsing by [[Diadema antillarum|long-spined sea urchins]] and grass-eating fish. ''Linear''-type patch reefs are found on the outer reefs, and are linear or curved. They occur in single or multiple rows, trending the same direction as the bank reefs on the outer reefs. Linear-type patch reefs often include [[Elkhorn coral]], which is rare on the dome-type patch reefs. As dead coral skeletons age and are weakened by the activities of boring [[sponges]], [[Marine worm|worms]], and [[mollusks]] and by wave action, parts of a patch reef may collapse. Patch reefs provide habitat for spiny lobsters and for many species of fish, including Bluehead wrasse (''[[Thalassoma bifasciatum]]''), [[damselfish]] (''Chromis'' spp.), Ocean surgeon, [[French angelfish|French]] and [[Queen angelfish|Queen]] angelfish (''Pomacanthus'' spp.), White, Caesar and Spanish grunts (''Haemulon'' ssp.), [[Yellowtail snapper|Yellowtail]] and other snappers, Redband and Stoplight [[parrotfish]] (''Sparisoma'' ssp.), [[Sergeant major (fish)|Sergeant major]] (''Abudefduf saxatilis''), Tomtate (''Haemulon aurolineatum''), [[Trumpetfish]] (''Aulostomus maculatus''), [[filefish]], groupers, snappers, [[Bar jack]] (''Caranx ruber''), Great barracuda, [[pufferfish]], [[squirrelfish]], [[cardinalfish]], and [[green moray]]s (''Gymnothorax funebris'').<ref>[http://www.flmnh.ufl.edu/fish/southflorida/coral/patchreef.html#patch ''Patch Reef Community'' Ichthyology at the Florida Museum of Natural History] Accessed December 15, 2010<br>Marszalek et alia:224, 227</ref>

Third is the ''bank reef'' community. Bank reefs are larger than patch reefs and are found on the outer reefs. Bank reefs consist of three zones. The ''reef flat'' is closest to the keys, and consists of [[coralline algae]] growing on fragments of coral skeletons. Further out to sea are the ''spur and groove formations'', low ridges of coral (the spurs) separated by channels with sand bottoms (the grooves). The shallowest parts of the spurs support [[fire coral]]s and [[Zoantharia|zoanthids]]. Starting at five or six feet deep, Elkhorn, star, and brain corals are the most important members of the community. Various types of gorgonians are also common. Beyond the spur and groove zone is the ''forereef'', which slopes down to the deeps. The upper forereef is dominated by star coral. At greater depths plate-like corals dominate, and then as the available light fades, sponges and non-reef building corals become common. Bank reefs provide habitat for various fishes, including French angelfish, Blue and Queen [[parrotfish]], [[Queen triggerfish]] (''Balistes vetula''), [[Rock beauty|Rock beauties]] (''Holacanthus tricolor''), [[Goatfish]] (''Parupeneus cyclostomus''), Porkfish (''[[Anisotremus virginicus]]'') and snappers. The sand found around and in the Florida Reef is composed of shell, coral skeleton and limestone fragments.<ref>[http://www.flmnh.ufl.edu/fish/southflorida/coral/Bankreef.html ''Bank Reef Community'' Ichthyology at the Florida Museum of Natural History] Accessed December 15, 2010</ref>

Other common species of hard coral found on the Florida Reef include [[Ivory Bush Coral]] (''Oculina diffusa''), which is the dominant coral in the patch reefs along the Florida coast north of the Florida Keys, [[Staghorn coral]] (''Acropora cervicornis''), Lettuce Coral (''Agaricia agaricites''), Grooved Brain Coral (''Diploria labrynthiformis''), Boulder Star Coral (''Monstastrea annularis''), Great Star Coral (''M. cavernosa''), Clubbed Finger Coral (''[[Porites]] porites'') and Massive Starlet Coral (''Siderastrea siderea'').<ref>[http://www.flmnh.ufl.edu/fish/southflorida/coral/Profiles.html ''Common Corals of Florida'' Ichthyology at the Florida Museum of Natural History] Accessed December 15, 2010<br>[http://www.flmnh.ufl.edu/fish/southflorida/coral/Distribution.html ''Coral Reefs Geographical Distribution'' Ichthyology at the Florida Museum of Natural History] Accessed December 15, 2010</ref>

==Threats to the reefs==
{{Also|Environmental issues with coral reefs|Coral reef protection}}
In common with coral reefs throughout the Caribbean and the world, the Florida Reef exhibits signs of stress and deterioration. Precht and Miller state that the numbers of Elkhorn and Staghorn corals (''[[Acropora]]'' ssp.) are declining to an extent that is unprecedented in several thousand years. Between 1981 and 1986, Staghorn corals declined by 96% at [[Molasses Reef]]. Between 1983 and 2000 at [[Looe Key]], Elkhorn corals declined by 93% and Staghorn corals by 98%. A joint reef monitoring program conducted by the [[United States Environmental Protection Agency]], Florida Marine Research Institute and [[National Oceanic and Atmospheric Administration]] recorded a loss of 6% to 10% living corals at 40 sampling stations from 1996 to 2000.<ref>Precht and Miller:241, 246, 267</ref>

Prolonged cold weather over southern Florida can lower sea water temperature enough to kill corals (Staghorn coral is killed by a water temperature of 13.5° C). The movement of cold fronts over Florida Bay and the Florida Keys have resulted in large kill offs of Elkhorn and Staghorn corals in the middle Keys and in the Dry Tortugas. Elevated temperatures also are damaging to coral reefs, causing [[coral bleaching]]. The first recorded bleaching incident on the Florida Reef was in 1973. Incidents of bleaching have become more frequent in recent decades, in correlation with a rise in [[sea surface temperature]]s. [[White band disease]] has also adversely affected corals on the Florida Reef. While hurricanes often can cause localized damage to Elkhorn and Staghorn corals, Precht and Miller state that the severe and widespread loss of those corals on the Florida Reef cannot be attributed to hurricane damage. Other possible causes of the losses of corals on the Florida Reef include [[epizootic]] diseases, [[eutrophication]], [[predation]], [[sedimentation]], [[overfishing]], [[ship grounding]]s, anchor dragging, commercial lobster and crab traps moved by storms, pollution, development on the Keys, growing numbers of visitors to the Keys and the reefs and the growth of seaweed on the coral.<ref>Precht and Miller:243-44, 245, 247-48, 249<br>[http://serc.fiu.edu/wqmnetwork/boyerj/pubs/NOAA%20Coral%20Florida%20Keys2008.pdf The State of Coral Reef Ecosystems of the Florida Keys] Accessed December 17, 2010</ref>

The long-spined sea urchin (''Diadema antillarum''), which browses on seaweed on and around reefs, was sharply reduced in numbers on the Florida Reef (and throughout the Caribbean) in the 1980s. While populations of this sea urchin have somewhat recovered elsewhere, its numbers are still very low on most of the Florida Reef, with the exception of the Dry Tortugas. As a consequence, there has been no effective check of the growth of seaweed on reef corals. However, the severe die-off of Elkhorn and Staghorn corals occurred before the die-off of the sea urchins, so that the proliferation of seaweed following the loss of the sea urchins was not the cause of the die-off of the corals, but may be retarding recovery by the corals.<ref>[http://faculty.mdc.edu/mchiappo/publications/diadema_urchin_paper_coral_reefs.pdf Large-scale surveys on the Florida Reef Tract indicate poor recovery of the long-spined sea urchin ''Diadema antillarum''] Accessed December 17, 2010<br>Precht and Miller:249<br>[http://serc.fiu.edu/wqmnetwork/boyerj/pubs/NOAA%20Coral%20Florida%20Keys2008.pdf The State of Coral Reef Ecosystems of the Florida Keys] Accessed December 17, 2010</ref>

Another threat to the Florida Reef is the ongoing [[Current sea level rise|rise in sea level]]. The sea level has risen almost six inches (15 cm) at [[Key West, Florida|Key West]] since 1913, and one foot (30 cm) since 1850. This rise in sea level increases the volume of water in Florida Bay significantly, and increases the exchange of water between the Bay and the water over the reefs. The lower salinity, higher turbidity and more variable temperature of the water from Florida Bay adversely affects the reefs. A continued rise in sea level would likely intensify the effect.<ref>[http://sofia.usgs.gov/publications/circular/1134/esns/cfsl.html U.S. Geological Survey Circular 1134 - Coral Reefs and Sea Level] Accessed December 16, 2010</ref>

A perceived deterioration of the reefs became a concern in the 1950s. Early attempts to protect the reefs led to the establishment in 1960 of a protected area that became John Pennekamp Coral Reef State Park. The creation of Biscayne National Monument (which later became Biscayne National Park) in 1968 protected the northern part of the Florida Reef. In 1990 the Florida Keys National Marine Sanctuary was established, bringing all of the Florida reef into federal or state protection.<ref>Precht and Miller:266</ref>

==Human use==

Human use of the reefs has grown tremendously in the past century. One measure of the growth is that registrations for recreational boats in Monroe County increased by 1000% from 1964 to 2006.<ref>[http://serc.fiu.edu/wqmnetwork/boyerj/pubs/NOAA%20Coral%20Florida%20Keys2008.pdf The State of Coral Reef Ecosystems of the Florida Keys] Accessed December 17, 2010</ref>

Recreational use of the Florida Reef and surrounding waters is popular and important to the economy of southern Florida, and in particular, of Monroe County. In 2000-2001 artificial and natural reefs in [[South Florida]] and Monroe County had 28 million person-days of recreational use by residents and tourists, including [[scuba diving]], fishing and viewing (as, for example, by [[snorkeling]]). These activities generated $4.4 million in sales, generated almost $2 million in local income and provided more than 70,000 full- and part-time jobs. The estimated asset value of the reefs was $8.5 billion. About two-thirds of the activity was related to natural reefs.<ref>[http://coralreef.noaa.gov/aboutcorals/values/tourismrecreation/ NOAA Coral Reef Conservation Program - Tourism and Recreation] Accessed December 17, 2010</ref>

In Monroe County for the period of June 2000 to May 2001 almost 5.5 million person-days of reef related activities resulted in $504 million in sales, which generated $140 million in income for 10,000 full- and part-time jobs. Almost two-thirds of the activity was by residents, and about half the activity involved fishing, with one-third involving snorkeling and one-sixth scuba diving.
<ref>[http://sanctuaries.noaa.gov/science/socioeconomic/floridakeys/pdfs/monroefact.pdf Socioeconomic Study of Reefs in Southeast Florida - Monroe County] Accessed December 17, 2010</ref>

In Miami-Dade County for the period from June 2000 to May 2001 a little over 6 million person-days of reef related activities resulted in $1,297 million in sales, which generated $614 million in income for 19,000 full- and part-time jobs. The activity was about evenly split between residents and tourists. As in Monroe County, about half the activity involved fishing, with one-third involving snorkeling and one-sixth scuba diving.<ref>[http://sanctuaries.noaa.gov/science/socioeconomic/floridakeys/pdfs/miamidadefact.pdf Socioeconomic Study of Reefs in Southeast Florida - Miami-Dade County] Accessed December 17, 2010</ref>

==Shipwrecks and lighthouses==

The [[Florida Current]] (which merges with the [[Antilles Current]] near the northern end of the barrier reef to form the [[Gulf Stream]]) passes close to the Florida Reef through the [[Straits of Florida]]. Ships began wrecking along the Florida Reef almost as soon as Europeans reached the [[New World]]. From early in the 16th century Spanish ships returning from the New World to Spain sailed from [[Havana]] to catch the Gulf Stream, which meant they passed close to the Florida Reef, with some wrecking on the reefs. In 1622, six ships of the [[Spanish treasure fleet]], including the ''[[Nuestra Señora de Atocha]]'', wrecked during a [[Tropical cyclone|hurricane]] in the lower Keys. In 1733, 19 ships of the Spanish treasure fleet wrecked during a hurricane in the middle and upper keys. In the 19th century the Straits became the major route for shipping between the eastern coast of the [[United States]] and ports in the [[Gulf of Mexico]] and the western [[Caribbean Sea]]. The combination of heavy shipping and a powerful current flowing close to dangerous reefs made the Florida Reef the site of many wrecks. By the middle of the 19th century ships were wrecking on the Florida Reef at the rate of almost once a week (the collector of customs in Key West reported a rate of 48 wrecks a year in 1848).<ref>Viele. Pp. 54-5</ref> Between 1848 and 1859 at least 618 ships were wrecked on the Florida Reef.<ref>Langley and Parks:5</ref> The Assistant United States Coast Surveyor reported that in the period from 1845 through 1849 almost one million (United States) dollars worth of vessels and cargos were lost on the reef.<ref>Blank:63</ref> The chief motivation for the [[Florida Railroad]], the first railroad to connect the Atlantic and Gulf coasts of Florida, was to allow goods to be transferred between ships in the Atlantic and in the Gulf of Mexico, thus avoiding the dangerous passage along the Florida Reef. [[Wrecking (shipwreck)#Wrecking in the Florida Keys|Salvaging wrecks on the reefs]] was the principal occupation in the Florida Keys through much of the 19th century, helping make Key West the biggest and richest city in Florida for a while.<ref>Viele 2001:3-14, 54-5, 166<br>Turner:27-8<br>Burnett:105<br>[http://www.monroecounty-fl.gov/pages/MonroeCoFL_Admin/about Facts about Monroe County] Accessed December 17, 2010</ref>

Some of the reefs in the Florida Reef are named after ships that wrecked on them. Fowey Rocks is named after [[HMS Fowey (1744)|HMS ''Fowey'']], which, however, actually wrecked on Ajax Reef. Looe Key is named after [[HMS Looe (1741)|HMS ''Looe'']]. [[Alligator Reef]] is named after the [[USS Alligator (1820)|USS ''Alligator'']].<ref>Viele 1999:26-31, 92-94</ref> [[Carysfort (reef)|Carysfort Reef]] is named after [[HMS Carysfort (1766)|HMS ''Carysfort'']], which ran aground on the reef, but did not sink.<ref>{{cite uscghist|FL}}</ref>

Soon after the United States acquired Florida from Spain in 1821, it began building [[lighthouse]]s along the Florida coast. The first lighthouses marking the Florida Reef were the [[Cape Florida Light]], at the northern end of the Reef, the [[Dry Tortugas Light]] (on Bush Key), marking the western end of the Reef, and the [[Key West Light]], all first lit in 1825. A [[light ship]] was placed at [[Carysfort Reef Light|Carysfort Reef]] in 1825, as well. [[Garden Key Light]], also in the Dry Tortugas, was added in 1826, and [[Sand Key Light]] (six nautical miles from [[Key West, Florida|Key West]]), was added in 1827. Large stretches of the Florida Reef remained unprotected by lighthouses, however. Keeping lights in operation along the Florida Reef proved difficult. The Carysfort Reef light ship was often blown out of position, and one time even onto a reef. The first light ship had to be replaced after just five years due to dry rot. The Cape Florida lighthouse was burned by [[Seminoles]] in 1836, and was not repaired and re-lit until 1847. The Key West and Sand Key lighthouses were destroyed by a hurricane in 1846. Starting at Carysfort Reef in 1852, [[skeletal tower]] lighthouses were built on submerged reefs to place lights as close to the outer edge of the Florida Reef as possible. With the completion of the [[American Shoal Light]] in 1880 there were finally navigation lights visible along the full length of the Florida Reef.<ref>Viele 2001:140, 154-59<br>[http://www.uscg.mil/history/weblighthouses/LHFL.asp United States Coast Guard Historic Light Station Information & Photography - Florida - American Shoal Light] Accessed December 16, 2010</ref>

In order to provide better charts for ships sailing along the Florida Reef, the Florida Keys, including the reef, and the waters to the west of the Keys, including Biscayne Bay and Florida Bay, were surveyed in the 1850s. The [[United States Army Corps of Engineers|United States Army Corps of Topographical Engineers]] established a base camp on Key Biscayne in 1849. The [[triangulation]] survey was conducted by the [[U.S. National Geodetic Survey|U.S. Coast Survey]] with men detailed from the U.S. Army and U.S. Navy. In 1855 [[Alexander Dallas Bache]], Superintendent of the U.S. Coast Survey, assumed personal direction of the survey. In 1851 [[Louis Agassiz]] was sent by the U.S. Coast Survey to study the Florida Reef.<ref>Blank:61-66</ref> His report on the reefs was published in 1880.<ref>[http://books.google.com/books?id=rroQAAAAIAAJ&printsec=frontcover&dq=%22Report+on+the+Florida+Reefs%22&source=bl&ots=GyFJ1GPgwb&sig=70-IAJtpXPkf3t2JPPkdHsTwXHU&hl=en&ei=jnMHTYvCE4H58AaioKjWCg&sa=X&oi=book_result&ct=result&resnum=1&sqi=2&ved=0CBkQ6AEwAA#v=onepage&q&f=false Agassiz, Louis. (1880) "Report on the Florida reefs." ''Memoirs of the Museum of Comparative Zoology'' VII:1. Harvard College.] Accessed December 14, 2010</ref>

==Notes==
{{reflist|3}}

==References==
*Blank, Joan Gill. (1996) ''Key Biscayne.'' Sarasota, Florida: Pineapple Press, Inc. ISBN 1-56164-096-4
*Burnett, Gene. (1991) ''Florida's Past: People and Events That Shaped the State. Volume 3.'' Sarasota, Florida: Pineapple Press. ISBN 1-56164-117-0 Found at [http://books.google.com/ Google books] Accessed December 17, 2010
*Langley, Wright and Arva Moore Parks (editors). (1983) "Diary of an Unidentified Land Official, 1855: Key West to Miami." ''Tequesta: The Journal of the Historical Association of Southern Florida.'' Number XLIII. Found at [http://ufdc.ufl.edu/UF00101446/00043/5j] Accessed December 19, 2010
*Marszalek, D. S., G. Babashoff, Jr., M. R. Noel and D. R. Worley. (1977) "Reef Distribution in South Florida." ''Proceedings, Third International Coral Reef Symposium.'' Rosenstiel School of Marine and Atmospheric Science, University of Miami. Found at [http://www.nova.edu/ocean/feingold/marszalek.pdf] Accessed December 18, 2010
*Precht, W. F. and S. L. Miller. (2007) "Ecological Shifts along the Florida Reef Tract: The Past as a Key to the Future." In R. B. Aronson. (Editor) ''Geological Approaches to Coral Reef Ecology.'' Found at [http://people.uncw.edu/millers/documents/Precht%20and%20Miller%20Ch.pdf] Accessed December 16, 2010
*Turner, Gregg. (2003) ''A Short History of Florida Railroads.'' Charleston, South Carolina: Arcadia Publishing. ISBN 0-7385-2421-2
*Viele, John. (1999) ''The Florida Keys: True Tales of the Perilous Straits.'' Sarasota, Florida: Pineapple Press, Inc. ISBN 1-56164-179-0
*Viele, John. (2001) ''The Florida Keys: The Wreckers.'' Sarasota, Florida: Pineapple Press, Inc. ISBN 1-56164-219-3

==External links==
*[http://www.eoearth.org/article/Coral_reefs_in_Florida "Coral reefs in Florida." The Encyclopedia of Earth]

{{Florida Keys}}

[[Category:Florida Keys]]
[[Category:Coral reefs of Florida]]

Florida Reef

2011-01-04T02:52:05Z

Jstuby: /* Reef structure and communities */several minor edits

The '''Florida Reef''' (also known as the '''Great Florida Reef''', '''Florida reefs''', '''Florida Reef Tract''' and '''Florida Keys Reef Tract''') is the only living [[Coral reef|coral barrier reef]] in the continental United States. It is the third largest coral barrier reef system in the world (after the [[Great Barrier Reef]] and [[Belize Barrier Reef]]).<ref>[http://coris.noaa.gov/portals/florida.html ''Florida'' NOAA's Coral Reef Information System] Accessed December 14, 2010</ref> It lies a few miles seaward of the [[Florida Keys]], is about 4 miles (6 to 7 km) wide and extends (along the 20 meter depth contour) 270 km (145 miles) from [[Fowey Rocks Light|Fowey Rocks]] just east of [[Soldier Key]] to just south of the [[Marquesas Keys]]. The barrier reef tract forms a great arc, concentric with the Florida Keys, with the northern end, in [[Biscayne National Park]], oriented north-south and the western end, south of the Marquesas Keys, oriented east-west. The rest of the reef outside Biscayne National Park lies within [[John Pennekamp Coral Reef State Park]] and the [[Florida Keys National Marine Sanctuary]]. Isolated coral patch reefs occur northward from Biscayne National Park as far as [[Stuart, Florida|Stuart]], in [[Martin County, Florida|Martin County]]. Coral reefs are also found in [[Dry Tortugas National Park]] west of the Marquesas Keys. There are more than 6,000 individual reefs in the system. The reefs are 5,000 to 7,000 years old, having developed since sea levels rose following the [[Wisconsinan glaciation]].<ref>[http://www.dep.state.fl.us/coastal/habitats/coral.htm ''Florida's Coral Reefs'' Florida Department of Environmental Protection] Accessed December 14, 2010.<br>[http://www.flmnh.ufl.edu/fish/southflorida/coral/conservation.html ''Florida Keys Conservation: National Marine Sanctuary'' Ichthyology at the Florida Museum of Natural History] Accessed December 14, 2010<br>Precht and Miller:243<br>Marszalek et alia:224</ref>

The densest and most spectacular reefs are found to the seaward of [[Key Largo]] (in and beyond John Pennekamp Coral Reef State Park) and [[Elliott Key]] where the two long keys help protect the reefs from the effects of water exchange with [[Florida Bay]], [[Biscayne Bay]], [[Card Sound]] and [[Barnes Sound]]. The bays and sounds (all between the Florida Keys and the mainland) tend to have lower [[salinity]], higher [[turbidity]] and wider temperature variations than the water in the open ocean. Channels between the Keys allow water from the bays to flow onto the reefs (especially in the middle Keys), limiting their growth.<ref>[http://sofia.usgs.gov/publications/circular/1134/esns/frt.html U.S. Geological Survey Circular 1134 - Florida Reef Tract] Accessed December 16, 2010<br>Precht and Miller:243<br>Marszalek et alia:228</ref>

==Reef structure and communities==
The Florida Reef consists of two ridges separated from the Florida Keys by the Hawk Channel. Closest to the Keys is a sand ridge called ''White Bank'', covered by large beds of sea grass, with patch reefs scattered across it. Further out to sea on the edge of the [[Florida Straits]] is the second ridge forming the outer reefs, covered by reefs and hard banks composed of coral rubble and sand.<ref>[http://sofia.usgs.gov/publications/circular/1134/esns/frt.html U.S. Geological Survey Circular 1134 - Florida Reef Tract] Accessed December 16, 2010</ref>

Almost 1,400 species of marine plants and animals, including more than 40 species of [[stony coral]]s and 500 species of fish, live on the Florida Reef. The Florida Reef lies close to the northern limit for tropical corals, but the species diversity on the reef is comparable to that of reef systems in the [[Caribbean Sea]].<ref>[http://sofia.usgs.gov/publications/circular/1134/esns/frt.html U.S. Geological Survey Circular 1134 - Florida Reef Tract] Accessed December 16, 2010</ref>

The [[Florida Museum of Natural History]] defines three communities on the Florida reefs. The ''hardbottom'' community lies closest to the Florida Keys and consists primarily of [[algae]], sea fans ([[gorgonian]]s) and stony corals growing on [[limestone]] rock that has a thin covering of sand. The stony corals in hardbottom communities include Smooth Starlet coral (''Siderastrea radians''), Mustard Hill Coral (''[[Porites astreoides]]''), Golfball coral (''Favia fragum''), Elliptical Star coral (''Dichocoenia stokesii'') and Common [[Brain coral]] (''Diploria strigosa''). Hardbottom provides habitat for [[anemone]]s, [[mollusk]]s, [[crab]]s, [[spiny lobster]]s, [[seastar]]s, [[sea cucumber]]s, [[tunicate]]s and various fish, including [[grunt]]s (''Haemulon'' spp.), [[snapper]]s (''Lutjanus'' spp.), [[grouper]]s (''Epinephelus'' spp.), [[tang]]s (''Acanthurus coeruleus''), [[Ocean surgeon]] (''Acanthurus bahianus'') and [[Great barracuda]] (''Spyraena barracuda'').<ref>[http://www.flmnh.ufl.edu/fish/southflorida/coral/Communities.html ''Hardbottom Community'' Ichthyology at the Florida Museum of Natural History] Accessed December 15, 2010</ref>

Second is the ''patch reef'' community. Patch reefs form in shallow water (three to six meters deep), some in Hawk Channel and some on the outer reef, but mainly on White Bank between Hawk Channel and the outer reefs. Patch reefs start from corals growing on a hard bottom, but grow upward as new corals establish themselves on the skeletons of dead corals. Most of the structure of patch reefs is formed from star (''[[Montastraea annularis]]'', ''Siderastrea siderea'') and [[brain coral|brain]] corals (''Diploria'' spp.). Other corals attach wherever there is an opening. Patch reefs may grow up to the surface of the water, and spread outwards. ''Dome''-type patch reefs (such as [[Hen and Chickens Reef]]), found in Hawk Channel and on White Bank, are round or elliptical, and are generally less than three meters high, but may reach up to nine meters high. Dome-type patch reefs are surrounded by sand which is kept clear due to browsing by [[Diadema antillarum|long-spined sea urchins]] and grass-eating fish. ''Linear''-type patch reefs are found on the outer reefs, and are linear or curved. They occur in single or multiple rows, trending the same direction as the bank reefs on the outer reefs. Linear-type patch reefs often include [[Elkhorn coral]], which is rare on the dome-type patch reefs. As dead coral skeletons age and are weakened by the activities of boring [[sponges]], [[Marine worm|worms]], and [[mollusks]] and by wave action, parts of a patch reef may collapse. Patch reefs provide habitat for spiny lobsters and for many species of fish, including Bluehead wrasse (''[[Thalassoma bifasciatum]]''), [[damselfish]] (''Chromis'' spp.), Ocean surgeon, [[French angelfish|French]] and [[Queen angelfish|Queen]] angelfish (''Pomacanthus'' spp.), White, Caesar and Spanish grunts (''Haemulon'' ssp.), [[Yellowtail snapper|Yellowtail]] and other snappers, Redband and Stoplight [[parrotfish]] (''Sparisoma'' ssp.), [[Sergeant major (fish)|Sergeant major]] (''Abudefduf saxatilis''), Tomtate (''Haemulon aurolineatum''), [[Trumpetfish]] (''Aulostomus maculatus''), [[filefish]], groupers, snappers, [[Bar jack]] (''Caranx ruber''), Great barracuda, [[pufferfish]], [[squirrelfish]], [[cardinalfish]], and [[green moray]]s (''Gymnothorax funebris'').<ref>[http://www.flmnh.ufl.edu/fish/southflorida/coral/patchreef.html#patch ''Patch Reef Community'' Ichthyology at the Florida Museum of Natural History] Accessed December 15, 2010<br>Marszalek et alia:224, 227</ref>

Third is the ''bank reef'' community. Bank reefs are larger than patch reefs and are found on the outer reefs. Bank reefs consist of three zones. The ''reef flat'' is closest to the keys, and consists of [[coralline algae]] growing on fragments of coral skeletons. Further out to sea are the ''spur and groove formations'', low ridges of coral (the spurs) separated by channels with sand bottoms (the grooves). The shallowest parts of the spurs support [[fire coral]]s and [[Zoantharia|zoanthids]]. Starting at five or six feet deep, Elkhorn, star, and brain corals are the most important members of the community. Various types of gorgonians are also common. Beyond the spur and groove zone is the ''forereef'', which slopes down to the deeps. The upper forereef is dominated by star coral. At greater depths plate-like corals dominate, and then as the available light fades, sponges and non-reef building corals become common. Bank reefs provide habitat for various fishes, including French angelfish, Blue and Queen [[parrotfish]], [[Queen triggerfish]] (''Balistes vetula''), [[Rock beauty|Rock beauties]] (''Holacanthus tricolor''), [[Goatfish]] (''Parupeneus cyclostomus''), Porkfish (''[[Anisotremus virginicus]]'') and snappers. The sand found around and in the Florida Reef is composed of shell, coral skeleton and limestone fragments.<ref>[http://www.flmnh.ufl.edu/fish/southflorida/coral/Bankreef.html ''Bank Reef Community'' Ichthyology at the Florida Museum of Natural History] Accessed December 15, 2010</ref>

Other common species of hard coral found on the Florida Reef include [[Ivory Bush Coral]] (''Oculina diffusa''), which is the dominant coral in the patch reefs along the Florida coast north of the Florida Keys, [[Staghorn coral]] (''Acropora cervicornis''), Lettuce Coral (''Agaricia agaricites''), Grooved Brain Coral (''Diploria labrynthiformis''), Boulder Star Coral (''Monstastrea annularis''), Great Star Coral (''M. cavernosa''), Clubbed Finger Coral (''[[Porites]] porites'') and Massive Starlet Coral (''Siderastrea siderea'').<ref>[http://www.flmnh.ufl.edu/fish/southflorida/coral/Profiles.html ''Common Corals of Florida'' Ichthyology at the Florida Museum of Natural History] Accessed December 15, 2010<br>[http://www.flmnh.ufl.edu/fish/southflorida/coral/Distribution.html ''Coral Reefs Geographical Distribution'' Ichthyology at the Florida Museum of Natural History] Accessed December 15, 2010</ref>

==Threats to the reefs==
{{Also|Environmental issues with coral reefs|Coral reef protection}}
In common with coral reefs throughout the Caribbean and the world, the Florida Reef exhibits signs of stress and deterioration. Precht and Miller state that the numbers of Elkhorn and Staghorn corals (''[[Acropora]]'' ssp.) are declining to an extent that is unprecedented in several thousand years. Between 1981 and 1986, Staghorn corals declined by 96% at [[Molasses Reef]]. Between 1983 and 2000 at [[Looe Key]], Elkhorn corals declined by 93% and Staghorn corals by 98%. A joint reef monitoring program conducted by the [[United States Environmental Protection Agency]], Florida Marine Research Institute and [[National Oceanic and Atmospheric Administration]] recorded a loss of 6% to 10% living corals at 40 sampling stations from 1996 to 2000.<ref>Precht and Miller:241, 246, 267</ref>

Prolonged cold weather over southern Florida can lower sea water temperature enough to kill corals (Staghorn coral is killed by a water temperature of 13.5° C). The movement of cold fronts over Florida Bay and the Florida Keys have resulted in large kill offs of Elkhorn and Staghorn corals in the middle Keys and in the Dry Tortugas. Elevated temperatures also are damaging to coral reefs, causing [[coral bleaching]]. The first recorded bleaching incident on the Florida Reef was in 1973. Incidents of bleaching have become more frequent in recent decades, in correlation with a rise in [[sea surface temperature]]s. [[White band disease]] has also adversely affected corals on the Florida Reef. While hurricanes often can cause localized damage to Elkhorn and Staghorn corals, Precht and Miller state that the severe and widespread loss of those corals on the Florida Reef cannot be attributed to hurricane damage. Other possible causes of the losses of corals on the Florida Reef include [[epizootic]] diseases, [[eutrophication]], [[predation]], [[sedimentation]], [[overfishing]], [[ship grounding]]s, anchor dragging, commercial lobster and crab traps moved by storms, pollution, development on the Keys, growing numbers of visitors to the Keys and the reefs and the growth of seaweed on the coral.<ref>Precht and Miller:243-44, 245, 247-48, 249<br>[http://serc.fiu.edu/wqmnetwork/boyerj/pubs/NOAA%20Coral%20Florida%20Keys2008.pdf The State of Coral Reef Ecosystems of the Florida Keys] Accessed December 17, 2010</ref>

The long-spined sea urchin (''Diadema antillarum''), which browses on seaweed on and around reefs, was sharply reduced in numbers on the Florida Reef (and throughout the Caribbean) in the 1980s. While populations of this sea urchin have somewhat recovered elsewhere, its numbers are still very low on most of the Florida Reef, with the exception of the Dry Tortugas. As a consequence, there has been no effective check of the growth of seaweed on reef corals. However, the severe die-off of Elkhorn and Staghorn corals occurred before the die-off of the sea urchins, so that the proliferation of seaweed following the loss of the sea urchins was not the cause of the die-off of the corals, but may be retarding recovery by the corals.<ref>[http://faculty.mdc.edu/mchiappo/publications/diadema_urchin_paper_coral_reefs.pdf Large-scale surveys on the Florida Reef Tract indicate poor recovery of the long-spined sea urchin ''Diadema antillarum''] Accessed December 17, 2010<br>Precht and Miller:249<br>[http://serc.fiu.edu/wqmnetwork/boyerj/pubs/NOAA%20Coral%20Florida%20Keys2008.pdf The State of Coral Reef Ecosystems of the Florida Keys] Accessed December 17, 2010</ref>

Another threat to the Florida Reef is the ongoing [[Current sea level rise|rise in sea level]]. The sea level has risen almost six inches (15 cm) at [[Key West, Florida|Key West]] since 1913, and one foot (30 cm) since 1850. This rise in sea level increases the volume of water in Florida Bay significantly, and increases the exchange of water between the Bay and the water over the reefs. The lower salinity, higher turbidity and more variable temperature of the water from Florida Bay adversely affects the reefs. A continued rise in sea level would likely intensify the effect.<ref>[http://sofia.usgs.gov/publications/circular/1134/esns/cfsl.html U.S. Geological Survey Circular 1134 - Coral Reefs and Sea Level] Accessed December 16, 2010</ref>

A perceived deterioration of the reefs became a concern in the 1950s. Early attempts to protect the reefs led to the establishment in 1960 of a protected area that became John Pennekamp Coral Reef State Park. The creation of Biscayne National Monument (which later became Biscayne National Park) in 1968 protected the northern part of the Florida Reef. In 1990 the Florida Keys National Marine Sanctuary was established, bringing all of the Florida reef into federal or state protection.<ref>Precht and Miller:266</ref>

==Human use==

Human use of the reefs has grown tremendously in the past century. One measure of the growth is that registrations for recreational boats in Monroe County increased by 1000% from 1964 to 2006.<ref>[http://serc.fiu.edu/wqmnetwork/boyerj/pubs/NOAA%20Coral%20Florida%20Keys2008.pdf The State of Coral Reef Ecosystems of the Florida Keys] Accessed December 17, 2010</ref>

Recreational use of the Florida Reef and surrounding waters is popular and important to the economy of southern Florida, and in particular, of Monroe County. In 2000-2001 artificial and natural reefs in [[South Florida]] and Monroe County had 28 million person-days of recreational use by residents and tourists, including [[scuba diving]], fishing and viewing (as, for example, by [[snorkeling]]). These activities generated $4.4 million in sales, generated almost $2 million in local income and provided more than 70,000 full- and part-time jobs. The estimated asset value of the reefs was $8.5 billion. About two-thirds of the activity was related to natural reefs.<ref>[http://coralreef.noaa.gov/aboutcorals/values/tourismrecreation/ NOAA Coral Reef Conservation Program - Tourism and Recreation] Accessed December 17, 2010</ref>

In Monroe County for the period of June 2000 to May 2001 almost 5.5 million person-days of reef related activities resulted in $504 million in sales, which generated $140 million in income for 10,000 full- and part-time jobs. Almost two-thirds of the activity was by residents, and about half the activity involved fishing, with one-third involving snorkeling and one-sixth scuba diving.
<ref>[http://sanctuaries.noaa.gov/science/socioeconomic/floridakeys/pdfs/monroefact.pdf Socioeconomic Study of Reefs in Southeast Florida - Monroe County] Accessed December 17, 2010</ref>

In Miami-Dade County for the period from June 2000 to May 2001 a little over 6 million person-days of reef related activities resulted in $1,297 million in sales, which generated $614 million in income for 19,000 full- and part-time jobs. The activity was about evenly split between residents and tourists. As in Monroe County, about half the activity involved fishing, with one-third involving snorkeling and one-sixth scuba diving.<ref>[http://sanctuaries.noaa.gov/science/socioeconomic/floridakeys/pdfs/miamidadefact.pdf Socioeconomic Study of Reefs in Southeast Florida - Miami-Dade County] Accessed December 17, 2010</ref>

==Shipwrecks and lighthouses==

The [[Florida Current]] (which merges with the [[Antilles Current]] near the northern end of the barrier reef to form the [[Gulf Stream]]) passes close to the Florida Reef through the [[Straits of Florida]]. Ships began wrecking along the Florida Reef almost as soon as Europeans reached the [[New World]]. From early in the 16th century Spanish ships returning from the New World to Spain sailed from [[Havana]] to catch the Gulf Stream, which meant they passed close to the Florida Reef, with some wrecking on the reefs. In 1622, six ships of the [[Spanish treasure fleet]], including the ''[[Nuestra Señora de Atocha]]'', wrecked during a [[Tropical cyclone|hurricane]] in the lower Keys. In 1733, 19 ships of the Spanish treasure fleet wrecked during a hurricane in the middle and upper keys. In the 19th century the Straits became the major route for shipping between the eastern coast of the [[United States]] and ports in the [[Gulf of Mexico]] and the western [[Caribbean Sea]]. The combination of heavy shipping and a powerful current flowing close to dangerous reefs made the Florida Reef the site of many wrecks. By the middle of the 19th century ships were wrecking on the Florida Reef at the rate of almost once a week (the collector of customs in Key West reported a rate of 48 wrecks a year in 1848).<ref>Viele. Pp. 54-5</ref> Between 1848 and 1859 at least 618 ships were wrecked on the Florida Reef.<ref>Langley and Parks:5</ref> The Assistant United States Coast Surveyor reported that in the period from 1845 through 1849 almost one million (United States) dollars worth of vessels and cargos were lost on the reef.<ref>Blank:63</ref> The chief motivation for the [[Florida Railroad]], the first railroad to connect the Atlantic and Gulf coasts of Florida, was to allow goods to be transferred between ships in the Atlantic and in the Gulf of Mexico, thus avoiding the dangerous passage along the Florida Reef. [[Wrecking (shipwreck)#Wrecking in the Florida Keys|Salvaging wrecks on the reefs]] was the principal occupation in the Florida Keys through much of the 19th century, helping make Key West the biggest and richest city in Florida for a while.<ref>Viele 2001:3-14, 54-5, 166<br>Turner:27-8<br>Burnett:105<br>[http://www.monroecounty-fl.gov/pages/MonroeCoFL_Admin/about Facts about Monroe County] Accessed December 17, 2010</ref>

Some of the reefs in the Florida Reef are named after ships that wrecked on them. |Fowey Rocks is named after [[HMS Fowey (1744)|HMS ''Fowey'']], which, however, actually wrecked on Ajax Reef. Looe Key is named after [[HMS Looe (1741)|HMS ''Looe'']]. [[Alligator Reef]] is named after the [[USS Alligator (1820)|USS ''Alligator'']].<ref>Viele 1999:26-31, 92-94</ref> [[Carysfort (reef)|Carysfort Reef]] is named after [[HMS Carysfort (1766)|HMS ''Carysfort'']], which ran aground on the reef, but did not sink.<ref>{{cite uscghist|FL}}</ref>

Soon after the United States acquired Florida from Spain in 1821, it began building [[lighthouse]]s along the Florida coast. The first lighthouses marking the Florida Reef were the [[Cape Florida Light]], at the northern end of the Reef, the [[Dry Tortugas Light]] (on Bush Key), marking the western end of the Reef, and the [[Key West Light]], all first lit in 1825. A [[light ship]] was placed at [[Carysfort Reef Light|Carysfort Reef]] in 1825, as well. [[Garden Key Light]], also in the Dry Tortugas, was added in 1826, and [[Sand Key Light]] (six nautical miles from [[Key West, Florida|Key West]]), was added in 1827. Large stretches of the Florida Reef remained unprotected by lighthouses, however. Keeping lights in operation along the Florida Reef proved difficult. The Carysfort Reef light ship was often blown out of position, and one time even onto a reef. The first light ship had to be replaced after just five years due to dry rot. The Cape Florida lighthouse was burned by [[Seminoles]] in 1836, and was not repaired and re-lit until 1847. The Key West and Sand Key lighthouses were destroyed by a hurricane in 1846. Starting at Carysfort Reef in 1852, [[skeletal tower]] lighthouses were built on submerged reefs to place lights as close to the outer edge of the Florida Reef as possible. With the completion of the [[American Shoal Light]] in 1880 there were finally navigation lights visible along the full length of the Florida Reef.<ref>Viele 2001:140, 154-59<br>[http://www.uscg.mil/history/weblighthouses/LHFL.asp United States Coast Guard Historic Light Station Information & Photography - Florida - American Shoal Light] Accessed December 16, 2010</ref>

In order to provide better charts for ships sailing along the Florida Reef, the Florida Keys, including the reef, and the waters to the west of the Keys, including Biscayne Bay and Florida Bay, were surveyed in the 1850s. The [[United States Army Corps of Engineers|United States Army Corps of Topographical Engineers]] established a base camp on Key Biscayne in 1849. The [[triangulation]] survey was conducted by the [[U.S. National Geodetic Survey|U.S. Coast Survey]] with men detailed from the U.S. Army and U.S. Navy. In 1855 [[Alexander Dallas Bache]], Superintendent of the U.S. Coast Survey, assumed personal direction of the survey. In 1851 [[Louis Agassiz]] was sent by the U.S. Coast Survey to study the Florida Reef.<ref>Blank:61-66</ref> His report on the reefs was published in 1880.<ref>[http://books.google.com/books?id=rroQAAAAIAAJ&printsec=frontcover&dq=%22Report+on+the+Florida+Reefs%22&source=bl&ots=GyFJ1GPgwb&sig=70-IAJtpXPkf3t2JPPkdHsTwXHU&hl=en&ei=jnMHTYvCE4H58AaioKjWCg&sa=X&oi=book_result&ct=result&resnum=1&sqi=2&ved=0CBkQ6AEwAA#v=onepage&q&f=false Agassiz, Louis. (1880) "Report on the Florida reefs." ''Memoirs of the Museum of Comparative Zoology'' VII:1. Harvard College.] Accessed December 14, 2010</ref>

==Notes==
{{reflist|3}}

==References==
*Blank, Joan Gill. (1996) ''Key Biscayne.'' Sarasota, Florida: Pineapple Press, Inc. ISBN 1-56164-096-4
*Burnett, Gene. (1991) ''Florida's Past: People and Events That Shaped the State. Volume 3.'' Sarasota, Florida: Pineapple Press. ISBN 1-56164-117-0 Found at [http://books.google.com/ Google books] Accessed December 17, 2010
*Langley, Wright and Arva Moore Parks (editors). (1983) "Diary of an Unidentified Land Official, 1855: Key West to Miami." ''Tequesta: The Journal of the Historical Association of Southern Florida.'' Number XLIII. Found at [http://ufdc.ufl.edu/UF00101446/00043/5j] Accessed December 19, 2010
*Marszalek, D. S., G. Babashoff, Jr., M. R. Noel and D. R. Worley. (1977) "Reef Distribution in South Florida." ''Proceedings, Third International Coral Reef Symposium.'' Rosenstiel School of Marine and Atmospheric Science, University of Miami. Found at [http://www.nova.edu/ocean/feingold/marszalek.pdf] Accessed December 18, 2010
*Precht, W. F. and S. L. Miller. (2007) "Ecological Shifts along the Florida Reef Tract: The Past as a Key to the Future." In R. B. Aronson. (Editor) ''Geological Approaches to Coral Reef Ecology.'' Found at [http://people.uncw.edu/millers/documents/Precht%20and%20Miller%20Ch.pdf] Accessed December 16, 2010
*Turner, Gregg. (2003) ''A Short History of Florida Railroads.'' Charleston, South Carolina: Arcadia Publishing. ISBN 0-7385-2421-2
*Viele, John. (1999) ''The Florida Keys: True Tales of the Perilous Straits.'' Sarasota, Florida: Pineapple Press, Inc. ISBN 1-56164-179-0
*Viele, John. (2001) ''The Florida Keys: The Wreckers.'' Sarasota, Florida: Pineapple Press, Inc. ISBN 1-56164-219-3

==External links==
*[http://www.eoearth.org/article/Coral_reefs_in_Florida "Coral reefs in Florida." The Encyclopedia of Earth]

{{Florida Keys}}

[[Category:Florida Keys]]
[[Category:Coral reefs of Florida]]

Key Largo Dry Rocks

2010-08-07T21:44:21Z

Jstuby: clarified position distinct from White Banks Dry Rocks, added SPA

'''Dry Rocks''' (or Key Largo Dry Rocks) is a [[coral reef]] located within the [[Florida Keys National Marine Sanctuary]]. It lies to the east of [[Key Largo]], within the Key Largo Existing Management Area, which is immediately to the east of [[John Pennekamp Coral Reef State Park]]. The reef lies within a Sanctuary Preservation Area (SPA). It is close to [[Grecian Rocks (reef)|Grecian Rocks]] and [[The Elbow (reef)|The Elbow]].

This reef is distinct from White Banks Dry Rocks, which is landward of [[Molasses Reef]] and [[French Reef]].

Approximate coordinates: {{Coord|25|07|20|N|80|18|00|W|source:NOAA_region:US-FL|display=inline,title}}

==References==
* [http://sanctuaries.noaa.gov/pgallery/atlasmaps/images/fkeast_2000.jpg NOAA National Marine Sanctuary Maps, Florida Keys East]
* [http://www.charts.noaa.gov/OnLineViewer/11464.shtml NOAA Navigational Chart 11464]

{{corals}}

[[Category:Marine biology]]
[[Category:Reefs of the Atlantic Ocean]]

Key Largo Dry Rocks

2010-08-04T18:02:05Z

Jstuby: corrected coordinates

Key Largo Dry Rocks

2010-08-04T17:58:22Z

Jstuby: /* References */ added navigational chart

'''Dry Rocks''' is a [[coral reef]] located within the [[Florida Keys National Marine Sanctuary]]. It lies to the east of [[Key Largo]], within the Key Largo Existing Management Area, which is immediately to the east of [[John Pennekamp Coral Reef State Park]].

Approximate coordinates: {{Coord|25|02|10|N|80|22|10|W|source:NOAA_region:US-FL|display=inline,title}}

==References==
* [http://sanctuaries.noaa.gov/pgallery/atlasmaps/images/fkeast_2000.jpg NOAA National Marine Sanctuary Maps, Florida Keys East]
* [http://www.charts.noaa.gov/OnLineViewer/11464.shtml NOAA Navigational Chart 11464]

{{corals}}

[[Category:Marine biology]]
[[Category:Reefs of the Atlantic Ocean]]

Key Largo Dry Rocks

2010-08-04T17:55:18Z

Jstuby: added coordinates

'''Dry Rocks''' is a [[coral reef]] located within the [[Florida Keys National Marine Sanctuary]]. It lies to the east of [[Key Largo]], within the Key Largo Existing Management Area, which is immediately to the east of [[John Pennekamp Coral Reef State Park]].

Approximate coordinates: {{Coord|25|02|10|N|80|22|10|W|source:NOAA_region:US-FL|display=inline,title}}

==References==
* [http://sanctuaries.noaa.gov/pgallery/atlasmaps/images/fkeast_2000.jpg NOAA National Marine Sanctuary Maps, Florida Keys East]

{{corals}}

[[Category:Marine biology]]
[[Category:Reefs of the Atlantic Ocean]]

Key Largo Dry Rocks

2010-07-31T02:08:55Z

Jstuby: added reference

'''Dry Rocks''' is a [[coral reef]] located within the [[Florida Keys National Marine Sanctuary]]. It lies to the east of [[Key Largo]], within the Key Largo Existing Management Area, which is immediately to the east of [[John Pennekamp Coral Reef State Park]].

==References==
* [http://sanctuaries.noaa.gov/pgallery/atlasmaps/images/fkeast_2000.jpg NOAA National Marine Sanctuary Maps, Florida Keys East]

{{corals}}

[[Category:Reefs]]
[[Category:Marine biology]]

Key Largo Dry Rocks

2010-07-31T01:35:57Z

Jstuby: article creation

Chert (Gestein)

2009-05-01T18:47:24Z

Jstuby: added image of chert beds

{{for|the Spanish municipality|Xert}}
[[Image:ChertUSGOVjpg.jpg|thumb|Chert]]
'''Chert''' ({{pron-en|ˈtʃɝːt}}) is a fine-grained [[silica]]-rich [[microcrystalline]], [[cryptocrystalline]] or [[microfibrous]] [[sedimentary rock]] that may contain small [[fossil]]s. It varies greatly in color (from white to black), but most often manifests as gray, brown, grayish brown and light green to rusty red; its color is an expression of trace elements present in the rock, and both red and green are most often related to traces of iron (in its oxidized and reduced forms respectively).

==Occurrence==
[[Image:Chert_beds_EverettPA.jpg|thumb|Chert (dark bands) in the [[Devonian]] Corriganville-New Creek limestone, Everett, Pennsylvania]]
Chert occurs as oval to irregular '''[[nodule]]s''' in [[greensand]], [[limestone]], [[chalk]], and [[dolostone]] formations as a replacement mineral, where it is formed as a result of some type of [[diagenesis]]. Where it occurs in [[chalk]], it is usually called [[flint]]. It also occurs in thin beds, when it is a primary deposit (such as with many jaspers and radiolarites). Thick beds of chert occur in deep [[geosyncline|geosynclinal]] deposits. These thickly bedded cherts include the [[novaculite]] of the [[Ouachita Mountains]] of [[Arkansas]], [[Oklahoma]], and similar occurrences in [[Texas]] in the [[United States]]. The [[banded iron formation]]s of [[Precambrian]] age are composed of alternating layers of chert and [[iron oxide]]s.

Chert also occurs in diatomaceous deposits and is known as diatomaceous chert. Diatomaceous chert consists of beds and lenses of [[diatomite]] which were converted during [[diagenesis]] into dense, hard chert. Beds of marine diatomaceous chert comprising strata several hundred meters thick have been reported from sedimentary sequences such as the [[Miocene]] [[Monterey Formation]] of California and occur in rocks as old as the Cretaceous.<ref>*Sam Boggs, Jr., "Principles of Sedimentology and Stratigraphy", Prentice Hall, 2006, 4th Ed., ISBN 0131547283</ref>

==Concerning the terms "chert", "chalcedony" and "flint"==
There is much confusion concerning the exact meanings and differences among the terms "chert", "[[chalcedony]]" and "[[flint]]" (as well as their numerous varieties). In [[petrology]] the term "chert" is used to refer generally to all rocks composed primarily of microcrystalline, cryptocrystalline and microfibrous quartz. The term does not include quartzite. Chalcedony is a microfibrous (microcrystaline with a fibrous structure) variety of quartz. Strictly speaking, the term "flint" is reserved for varieties of chert which occur in chalk and marly limestone formations. <ref>George R. Rapp, "Archaeomineralogy", 2002. ISBN 3-540-42579-9</ref> <ref>Barbara E. Luedtke, "The Identification of Sources of Chert Artifacts", American Antiquity, Vol. 44, No.4 (Oct., 1979), 744-757.</ref> Among non-geologists (in particular among archaeologists), the distinction between "flint" and "chert" is often one of quality - chert being lower quality than flint. This usage of the terminology is prevalent in America and is likely caused by early immigrants who imported the terms from England where most true flint (that found in chalk formations) was indeed of better quality than "common chert" (from limestone formations). Among petrologists, chalcedony is sometimes considered separately from chert due to its fibrous structure. Since many cherts contain both microcrystaline and microfibrous quartz, it is sometimes difficult to classify a rock as completely chalcedony, thus its general inclusion as a variety of chert.

==Chert and Precambrian fossils==
[[Image:MichiganBIF.jpg|thumb|Precambrian [[Banded Iron Formation]] specimen from Upper Michigan showing red chert layers.]]
The [[cryptocrystalline]] nature of chert, combined with its above average ability to resist [[weathering]], [[recrystallisation]] and [[metamorphism]] has made it an ideal rock for preservation of early life forms<ref>[http://www.uni-muenster.de/GeoPalaeontologie/Palaeo/Palbot/seite1.html THE EARLIEST LIFE: Annotated listing]</ref>.

For example:
*The 3.2 Ga chert of the [[Fig Tree Formation]] in the Barbeton Mountains between [[Swaziland]] and [[South Africa]] preserved non-colonial [[unicellular]] bacterial-like fossils<ref>[http://www.lpi.usra.edu/meetings/marsmet98/pdf/7033.pdf Fig Tree Formation of South Africa]</ref>.
*The [[Gunflint Chert]] of western Ontario (1.9 to 2.3 Ga) preserves not only [[bacterium|bacteria]] and [[cyanobacteria]] but also organisms believed to be ammonia-consuming and some that resemble [[green algae]] and fungus-like organisms<ref>[http://gsc.nrcan.gc.ca/paleochron/05_e.php Gunflint chert]</ref>.
*The [[Apex Chert]] (3.4 Ga) of the [[Pilbara craton]], [[Australia]] preserved eleven taxa of [[prokaryotes]]<ref>[http://www.lpi.usra.edu/meetings/lpsc2003/pdf/1267.pdf BIOGENICITY OF MICROFOSSILS IN THE APEX CHERT]</ref>.
*The Bitter Springs Formation of the Amadeus Basin, Central Australia, preserves 850 Ma cyanobacteria and algae<ref>[http://www.ucmp.berkeley.edu/precambrian/bittersprings.html Cyanobacertial fossils of the Bitter Springs Chert, UMCP Berkley]</ref>.
*The [[Devonian]] [[Rhynie chert]] (400 Ma) of Scotland has the oldest remains of land flora, and the preservation is so perfect that it allows cellular studies of the fossils.

==Prehistoric and historic uses==
In prehistoric times, chert was often used as a raw material for the construction of [[stone tool]]s. Like [[obsidian]], as well as some [[rhyolite]]s, [[felsite]]s, [[quartzite]]s, and other [[tool stone]]s used in [[lithic reduction]], chert fractures in a [[Hertzian cone]] when struck with sufficient force. This results in conchoidal fractures, a characteristic of all minerals with no [[Cleavage (crystal)|cleavage]] planes. In this kind of fracture, a cone of force propagates through the material from the point of impact, eventually removing a full or partial cone; this result is familiar to anyone who has seen what happens to a plate-glass window when struck by a small object, such as an airgun projectile. The partial Hertzian cones produced during lithic reduction are called [[lithic flake|flake]]s, and exhibit features characteristic of this sort of breakage, including [[striking platform]]s, [[bulb of force|bulbs of force]], and occasionally [[eraillure]]s, which are small secondary flakes detached from the flake's bulb of force.

When a chert stone is struck against steel, sparks result. This makes it an excellent tool for starting fires, and both flint and common chert were used in various types of fire-starting tools, such as [[tinderbox]]es, throughout history. A primary historic use of common chert and flint was for [[flintlock]] [[firearms]], in which the chert striking a metal plate produces a spark that ignites a small reservoir containing [[black powder]], discharging the firearm.

In some areas, chert is [[ubiquitous]] as stream gravel and fieldstone and is currently used as construction material and road surfacing. Part of chert's popularity in road surfacing or driveway construction is that rain tends to firm and compact chert while other fill often gets muddy when wet. However, where cherty gravel ends up as fill in concrete, the slick surface can cause localized failure. Hauled prices for chert of less than $10 – $15 per ton are not uncommon in many parts of the U.S.

Chert has been used in late 19th-century and early 20th-century [[headstone]]s or grave markers in Tennessee and other regions.

==Varieties of chert==
There are numerous varieties of chert, classified based on their visible, microscopic and physical characteristics.<ref>W.L. Roberts, T.J. Campbell, G.R. Rapp Jr., "Encyclopedia of Mineralogy, Second Edition", 1990. ISBN 0-442-27681-8</ref> <ref>R.S. Mitchell, "Dictionary of Rocks", 1985. ISBN 0-442-26328-7</ref> Some of the more common varieties are:
*[[Flint]] is a compact microcrystaline quartz. It is found in [[chalk]] or marly limestone formations and is formed by a replacement of calcium carbonate with [[silica]]. It is commonly found as nodules. This variety was often used in past times to make bladed tools.
*"Common chert" is a variety of chert which forms in limestone formations by replacement of calcium carbonate with silica. This is the most abundantly found variety of chert. It is generally considered to be less attractive for producing gem stones and bladed tools than [[flint]].
*[[Jasper]] is a variety of chert formed as primary deposits, found in or in connection with magmatic formations which owes its red color to iron(III) inclusions. Jasper frequently also occurs in black, yellow or even green (depending on the type of iron it contains). Jasper is usually opaque to near opaque.
*[[Radiolarite]] is a variety of chert formed as primary deposits and containing [[radiolarian]] microfossils.
*[[Chalcedony]] is a microfibrous quartz.
*[[Agate]] is distinctly banded chalcedony with successive layers differing in colour or value.
*[[Onyx]] is a banded agate with layers in parallel lines, often black and white.
*[[Opal]] is a hydrated silicon dioxide. It is often of a [[Neogene|Neogenic]] origin. In fact is not a mineral (it is a [[mineraloid]]) and it is generally not considered a variety of chert, although some varieties of opal (opal-C and opal-CT) are microcrystaline and contain much less water (sometime none). Often people without petrological training confuse opal with chert due to similar visible and physical characteristics.
*[[Magadi-type chert]] is a variety that forms from a sodium silicate precursor in highly alkaline lakes such as [[Lake Magadi]] in Kenya.
*Porcelanite is a term used for fine-grained siliceous rocks with a texture and a fracture resembling those of unglazed porcelain.
*[[Siliceous sinter]] is porous, low-density, light-colored siliceous rock deposited by waters of hot springs and geysers.
Other lesser used terms for chert (most of them archaic) include, firestone, silex, silica stone and flintstone.

==See also==
*[[Nodule (geology)]] not to be confused with [[Concretion]]
*[[Agate]]
*[[Chalcedony]]
*[[Eolith]]
*[[Flint]]
*[[Jasper]]
*[[Obsidian]]
*[[Onyx]]
*[[Opal]]
*[[Whinstone]]

==References==
{{Reflist}}
*[http://www.globalcommunity.org/wtt/walk_photos/3200.htm Photo & note re: Fig Tree Formation]
*[http://www2.bc.edu/~strother/GE_146/labs/lab7/Archaean.html Microphotographs of Fig Tree fossils]
*Schopf, J.W. (1999) ''Cradle of Life: The Discovery of Earth's Earliest Fossils'', Princeton University Press, 336 p. ISBN 0-691-00230-4
* [http://virtual.parkland.edu//lstelle1/len/biface_guide/chert/documents/chert_types.html An Archaeological Guide To Chert Types Of East-Central Illinois]

{{Silica minerals}}

{{Commonscat|Chert}}

[[Category:Petrology]]
[[Category:Minerals]]
[[Category:Mineralogy]]
[[Category:Sedimentary rocks]]
[[Category:Lithics]]
[[Category:Quartz varieties]]


[[zh-min-nan:Hoé-chio̍h]]
[[ca:Sílex]]
[[cs:Buližník]]
[[cy:Callestr]]
[[da:Flint]]
[[de:Hornstein (Gestein)]]
[[et:Ränikivi]]
[[es:Sílex]]
[[eo:Siliko]]
[[fr:Silex]]
[[id:Rijang]]
[[it:Selce]]
[[he:צור (סלע)]]
[[la:Silex]]
[[lv:Krams]]
[[lt:Titnagas]]
[[nl:Vuursteen]]
[[ja:チャート (岩石)]]
[[no:Flint]]
[[nn:Flint]]
[[pl:Krzemień]]
[[pt:Sílex]]
[[ro:Silicolit]]
[[ru:Кремень]]
[[simple:Chert]]
[[sk:Silicit]]
[[sl:Kremen]]
[[fi:Piikivi]]
[[sv:Flinta]]
[[th:หินเชิร์ต]]
[[uk:Кремінь]]
[[vi:Đá lửa (lịch sử)]]
[[zh:燧石]]

Wiwaxia

2009-04-12T18:31:24Z

Jstuby: reorganized three images into new gallery

{{see|Halwaxiida}}
{{Taxobox
| fossil_range = Early–Middle [[Cambrian]]
| image = Wiwaxia_corrugata.jpg
| regnum = [[Animal]]ia
| superphylum = [[Lophotrochozoa]]
| phylum = ''[[incertae sedis]]
| unranked_classis = [[Halwaxiida]]
| familia = '''Wiwaxiidae'''
| familia_authority = Walcott, 1911
| genus = '''''Wiwaxia'''''
| binomial = ''Wiwaxia corrugata''
| binomial_authority = Walcott, 1911
}}

'''''Wiwaxia''''' is genus of soft-bodied, scale-covered animals known from [[Burgess shale]] type {{lagerstatte}} dating from the Early to Middle Cambrian.<ref name="Zhao1994" /><ref name="ConwayMorris1985" /> The organisms are mainly known from dispersed sclerites; articulated specimens, where found, range from {{convert|3.4|mm|in}} to a little over {{convert|5|cm|in}} in length. The precise taxonomic affinities of the genus are a matter of ongoing debate amongst palaeontologists.

==History of discovery==
''Wiwaxia'' was originally described by W.D. Matthew in 1899 from an isolated spine that had been found earlier in the Ogyopsis Shale, and classified as a [[hyolith]]id.<ref name="ConwayMorris1985" /> Further specimens were found by in 1911 by American [[paleontologist]] [[Charles Doolittle Walcott]] as a result of one of his field trips to the nearby [[Burgess Shale]] in the Canadian [[Rocky Mountains]], and he classified it as a member of the [[polychaete]] group of [[annelid]] worms.<ref name="Walcott1911" />

In 1966 and 1967 a team led by [[Harry B. Whittington]] revisited the Burgess Shale and found so many fossils that it took years to analyze them all, and ''Wiwaxia'' was one of the most difficult to analyze.<ref>{{cite book
| author=[[Stephen Jay Gould| Gould, S.J.]] | title=Wonderful Life | publisher= Hutchinson Radius
| location=London | date=1990 | isbn=0091742714 | pages=77 and p. 189
}}</ref> Eventually in 1985 [[Simon Conway Morris]], then a member of Whittington's team, published a detailed description that concluded ''Wiwaxia'' was not a polychaete.<ref name="ConwayMorris1985">{{cite journal
| author = Conway Morris, S. | year = 1985
| title = The Middle Cambrian metazoan Wiwaxia corrugata (Matthew) from the Burgess Shale and Ogygopsis Shale, British Columbia, Canada
| journal=Philosophical Transactions of the Royal Society of London, Series B
| volume = 307 | pages = 507–582 | doi=10.1098/rstb.1985.0005
| url=http://www.jstor.org/pss/2396338 | accessdate=2008-08-04
}}</ref> All the known specimens came from in and around the Burgess Shale until 1991, when fragmentary fossils were reported from Australia's Georgina Basin.<ref>{{ cite journal
| author=Southgate, P.N., and Shergold, J.H. | date=1991
| title=Application of sequence stratigraphic concepts to Middle Cambrian phosphogenesis, Georgina Basin, Australia
| journal=Journal of Australian Geology and Geophysics | volume=12 | pages=119-144
}}</ref> In 2004 additional finds which may represent two different species were reported from the same area.<ref name="Porter2004HalkieriidsMidCambrianAustralia">{{ cite journal
| author=Porter, S.M. | date=May 2004 | accessdate=2008-08-01
| url=http://findarticles.com/p/articles/mi_qa3790/is_200405/ai_n9377598/pg_1?tag=artBody;col1
| title=Halkieriids in Middle Cambrian Phosphatic Limestones from Australia
| journal=Journal of Paleontology | volume=78 |issue=3 | pages=574-590
| doi=10.1666/0022-3360(2004)078<0574:HIMCPL>2.0.CO;2
}}</ref>

==Occurrence==
Reasonably complete specimens have been found in the [[Burgess Shale]], and fragmentary specimens in in nearby strata slightly older than and younger than the Burgess Shale,<ref name="ConwayMorris1985" /> in [[China]]'s Kaili Formation<ref name="Zhao1994">{{cite journal
| author = Zhao, Y.L. | coauthors = Qian, Y.; Li, X.S.
| year = 1994
| title = Wiwaxia from Early-Middle Cambrian Kaili Formation in Taijiang, Guizhou
| journal = Acta Palaeontologica Sinica | volume = 33 | issue = 3 | pages = 359–366
| url=http://www.jstor.org/pss/1307127 | accessdate=2008-08-04
}}</ref> and in [[Australia]]'s Georgina Basin.<ref name="Porter2004HalkieriidsMidCambrianAustralia" /> All of these locations are dated to the Middle [[Cambrian]] period, and the Burgess Shale has been dated to {{ma|505}}.<ref>{{cite web
| title = Age of Burgess Shale
| url=http://palaeo.gly.bris.ac.uk/palaeofiles/lagerstatten/Burgess/Setting.html
| work = Burgess Shale | publisher = Bristol University | accessdate = 2007-09-05
}}</ref> These finds show that ''Wiwaxia'' and most of the other [[Burgess shale type fauna| Burgess Shale type fauna]] were very widespread.<ref name="Zhao1994" /><ref>{{ cite web
| url=http://paleobiology.si.edu/burgess/cambrianWorld.html | title=The Cambrian World
| accessdate=2008-08-04 }} Reconstruction of the Burgess Shale and map of the world in Mid-Cambrian times.</ref>

==Description==
{| style="float:right; width:300px" | border="0" | cellpadding=3 cellspacing=0"
|-
| {{Annotated image | float=right | caption=''[[Wiwaxia]]'' sclerite zones, seen from front| image=Wiwaxia body zones.png | width=300 | height=110| image-width=150 | image-left=93 | image-top=0
| annotations =
{{Annotation|90|25|Spine}}
{{Annotation|150|40|Dorsal}}
{{Annotation|64|60|Upper lateral}}
{{Annotation|201|70|Lower lateral}}
{{Annotation|63|79|Ventro-lateral}}
{{Annotation|173|96|<span style{{=}}"background-color:#753a00">      </span> {{=}} Frontal}}
}}
|-
| {{Annotated image | float=right | caption=''[[Wiwaxia]]'' viewed from top (moving up) and right| image=Wiwaxia plan n elev.png | width=300 | height=130 image-width=300 | image-left=0 | image-top=0
| annotations =
}}
|}
This concentrates on the species ''Wiwaxia corrugata'', found in the Burgess Shale, since the other specimens consist only of fragments, while the Burgess Shale has provided at least 138 complete ones.<ref name="ConwayMorris1985" /><ref name="Porter2004HalkieriidsMidCambrianAustralia" />

''Wiwaxia'' was a [[bilaterally symmetrical]] animal. Viewed from the top the body was [[elliptical]] with no distinct head or tail, and from the front or rear it was almost [[rectangular]]. The most complete fossils fall into two size ranges: {{convert|2|cm|in}} to {{convert|5|cm|in}} long, which are thought to be adults; and {{convert|3.4|mm|in}} to {{convert|1.5|cm|in}}, which are thought to be juveniles. Estimating their height is difficult because specimens were compressed after death; a specimen of the average length, {{convert|3.4|mm|in}}, may have been {{convert|1|cm|in}} high excluding the spines on their backs. The ratio of width to length does not appear to change as the animals grew.<ref name="ConwayMorris1985" />

The animal was covered in small ribbed armor plates called [[sclerites]], that lay flat against the body, overlapped so that the rear of one covered the front of the one behind, and formed five main regions — the top, with 8-9 rows of sclerites; the upper part of the sides, with 11-12; the lower part of the sides, with 8; the front; and the area nearest the sea-floor, with 12-17 rows.<ref name="EibyeJacobsen2004" /> Most of the sclerites were shaped like oval leaves, but the ventro-lateral ones, nearest the sea-floor, were [[crescent]]-shaped, rather like flattened [[banana]]s, and formed a single row with the tips pointing down. In addition there were two rows of ribbed spines running from to rear, one along each side of the top surface, and projecting out and slightly upwards, with a slight upwards curve near the tips. Specimens ranging from {{convert|11|mm|in}} {{convert|52|mm|in}} have about the same number of ventro-lateral sclerites just above the foot. On the other hand the number of spines seems to depend on the size of the specimen, up to about 12 per side. The number and spacing of the spines is asymmetrical in the specimens found, and this may have been natural rather than a result of events in the animal's life or after death. Although the spines in the middle of each row are usually the longest, up to {{convert|5|cm|in}}, a few specimens have rather short middle spines, perhaps because these were part-grown replacements. The smallest specimens may have lacked the long dorsal spines, which appear to have grown quickly in larger juveniles and then more slowly in adults.<ref name="ConwayMorris1985" />

{{Annotated image | float=right | caption=''[[Wiwaxia]]'' spine, seen from front and side| image=Wiwaxia spines 01.png | width=200 | height=124| image-width=200 | image-left=0 | image-top=0
| annotations =
{{Annotation|80|40|"Blade"}}
{{Annotation|80|100|<span style{{=}}"background-color:#ff8080">      </span> {{=}} Root}}
}}
Each sclerite was rooted separately in the body; the roots of body sclerites are 40% of the external length or a little less, while the roots of the spines are a little over 25% of the external length; all were rooted in pockets in the skin, rather like the [[Hair follicle| follicle]]s of [[mammal]]ian [[hair]]. The roots of the body sclerites were significantly narrower than the sclerites, but the spines had roots about as wide as their bases; both types of root were made of fairly soft tissue. The sclerites and spines were not mineralized, and the frayed appearance of some broken ones suggests a fibrous structure. They way they were preserved suggests they were not made of [[chitin]], from which [[insect]]s' [[exoskeletons]] are formed. They may have been made of [[tanning| tanned]] proteins or of [[collagen]], which is the main component of [[cartilage]]s and [[tendon]]s in humans. Since the body sclerites had bases that were narrower than the hard external parts, it is hard to see how they grew. They may have enclosed soft tissue that could have [[secrete]]d the hard walls, but there is no convincing evidence for this.<ref name="ConwayMorris1985" /> Butterfield (1990) examined some sclerites under both [[Optical microscope| optical]] and [[scanning electron microscope]]s and concluded that they were not hollow, and that the bases split and spread to form the blades, a pattern that is also seen in [[monocot]] leaves.
<ref name="Butterfield1990" />

[[Image:Wiwaxia feeding apparatus 01.png| thumb | right | ''[[Wiwaxia]]'' usually had two tooth-rows: opened for feeding (left); folded (right). In both cases the front of the animal is at the top. ]]
''Wiwaxia''’s flat underside was soft and unarmored. Little is known of the internal anatomy, although the gut apparently ran straight and all the way from the front to the rear. At the the front end of the gut, about {{convert|5|mm|in}} from the animal's front in an average specimen about {{convert|2.5|cm|in}} long, there was a feeding apparatus that consisted of two (or in rare large specimens three) rows of backward-pointing conical teeth. The feeding apparatus was tough enough to be frequently preserved, but unmineralized and fairly flexible, as it folded and retracted when not in use. It would have had to pushed forward out of the mouth in order to feed. Even the smallest specimens have this type of apparatus, with two rows containing the same number of teeth as in larger ones. This indicates that ''Wiwaxia''’s feeding habits remained the same throughout its life after the [[larva]]l stage. The feeding apparatus may have acted as a [[rasp]] to scrape [[bacteria]] off the top of the [[microbial mat]] that covered the sea-floor, or as a [[Rake (tool)| rake]] to gather food particles that lay on the sea-floor.<ref name="ConwayMorris1985" />

Since there is no sign of eyes or tentacles, ''Wiwaxia'' may have relied mainly on chemical senses such as smell and taste. Its [[respiratory]] system is also unknown.<ref name="ConwayMorris1985" />

One juvenile specimen appears to be preserved while [[molt]]ing and not yet completely detached from its discarded armor. Its new set of spines seem less rigid than the old ones and slightly underdeveloped, as if the next stages were going to be inflated by body fluids and then hardening. The new armor may have had an internal volume 50% to 70% larger than the old one. Molting appears to have occurred all at once, as adult specimens shows no signs of interruptions in the sclerite armor that would indicate molting of parts of the armor or of individual sclerites. Since the bases of the body sclerites are relatively narrow and these is no sign of sclerites splitting during molting, withdrawing soft tissue from the old sclerites would probably have required the tissues to be broken down in to a more fluid form, as happens in the claws of lobsters and crabs when they molt. The skin must also have been shed, since the discarded armor appears as a complete unit rather than scattered sclerites. In the juvenile that was apparently molting when it died, the feeding apparatus also appears to have been shed, as half of one tooth row is pointing forwards.<ref name="ConwayMorris1985" />

The long dorsal spines may have been a defense against predators, and finds of broken spines suggest that ''Wiwaxia'' was attacked. The animal appears to have crawled on the surface of the sea-floor feeding on particles that fell from higher levels of the sea. ''Wiwaxia'' shows no signs of legs and was probably too large to move on [[cilia]], so it probably moved by muscular contraction that made its foot ripple. Juveniles may have burrowed into the sea-floor. In one specimen a small [[brachiopod]], ''[[Diraphora]] bellicostata'', appears to be attached to one of the ventro-lateral sclerites. This suggests that adult ''Wiwaxia'' did not burrow or even plough much into the sea-floor as they moved. Two other specimens of ''[[Diraphora]] bellicostata'' have been found attached to dorsal sclerites. ''Wiwaxia'' appears to have been solitary rather than gregarious.<ref name="ConwayMorris1985" />

==Classification==

During the Cambrian, most of the [[phylum|main groupings of animals]] recognised today were beginning to diverge. Consequently, many lineages (that would later become extinct) appear intermediate to two more more modern groups, or lack features common to all modern members of a group, and hence fall into the "[[stem group]]" of a modern [[taxon]].<ref>{{ cite journal
| author=Budd, G.E. | title=The Cambrian Fossil Record and the Origin of the Phyla
| journal=Integrative and Comparative Biology | date=2003 | volume=43 | issue=1 | pages=157-165
| doi=10.1093/icb/43.1.157 | url=http://icb.oxfordjournals.org/cgi/content/full/43/1/157
| accessdate= 2006-08-20
}}</ref> Debate is ongoing as to whether ''Wiwaxia'' can be placed within a modern crown group and, if it cannot, in which group's stem it falls. When Walcott first described ''Wiwaxia'', he regarded it as a [[polychaete]] [[annelid]] worm, and its [[sclerite]]s as similar to the [[elytra]] ("scales") of annelids.<ref name=Walcott1911>{{cite journal
| author = Walcott, C.D. | authorlink = Charles Doolittle Walcott | year = 1911
| title = Middle Cambrian annelids. Cambrian geology and paleontology, II
| journal = Smithsonian Miscellaneous Collections | volume = 57 | pages = 109–144
}}</ref> More recently the debate has been intense, and proposed classifications include: a member of an extinct [[phylum]] distantly related to the molluscs; a crown-group polychaete; a stem-group annelid; a problematic bilaterian; a stem- or possibly primitive crown-group mollusc.<ref name="Butterfield2006" />

In 1985 [[Simon Conway Morris]] agreed that there were similarities to polychaetes, but considered that ''Wiwaxia''’s sclerites were different in construction to annelids' elytra. He was more impressed by the similarites between ''Wiwaxia''’s feeding apparatus and a [[mollusc]]an [[radula]], and assigned the animal to a new taxon Molluscata, which he proposed should also contain the molluscs and [[Hyolitha| hyolithid]]s.<ref name="ConwayMorris1985" /> When he later described the first fairly complete specimens of ''[[Halkieria]]'', he suggested that these were closely related to ''Wiwaxia''.<ref name="ConwayMorrisPeel1990">{{ cite journal
| title=Articulated halkieriids from the Lower Cambrian of north Greenland
| author=Conway Morris, S., and Peel, J.S. | journal=Nature | volume=345 | pages=802–805
| date=June 1990 | doi=10.1038/345802a0
| url=http://www.nature.com/nature/journal/v345/n6278/abs/345802a0.html | accessdate=2008-07-31
}} A short but free account is given at {{ cite web |
| url=http://www.stephenjaygould.org/library/naturalhistory_cambrian.html
| title=Showdown on the Burgess Shale | accessdate=2008-07-31
}}</ref>

Nick Butterfield, then a postgraduate paleontologist at Harvard inspired by [[Stephen Jay Gould]]'s lectures, agreed that the sclerites were not like elytra, which are relatively fleshy and soft. However, since the sclerites were solid, he concluded that ''Wiwaxia'' could not be a member of the "Coeloscleritophora", a [[taxon]] that had been proposed in order to unite organisms with hollow sclerites, and could not be closely related to the [[halkieriid]]s, which have hollow sclerites. Instead he thought that they were very similar in several ways to the
[[chitin]]ous bristles ([[setae]]) that project from the bodies of modern annelids and in some [[genus| genera]] form leaf-like scales that cover the back like roof tiles - in composition, in detailed structure, in how they were attached to the body via "[[Hair follicle|follicle]]s" and in overall appearance. Some modern annelids also develop on each side rows of longer bristles, which both Walcott and Butterfield considered similar to ''Wiwaxia''’s dorsal spines.<ref name="Butterfield1990">{{cite journal
| author=Butterfield, N.J. | year=1990
| title=A reassessment of the enigmatic Burgess Shale fossil ''Wiwaxia corrugata'' (Matthew) and its relationship to the polychaete ''Canadia spinosa''. Walcott
| journal=Paleobiology | volume=16 | pages=287–303
| url=http://www.jstor.org/stable/2400789 | accessdate=2008-08-05
}}</ref> including the [[halkieriid]]s.

Butterfield also contended that ''Wiwaxia''’s feeding apparatus, instead of being mounted in the middle of its "head", was just as likely to be mounted in two parts on the sides of the "head", an arrangement that is common in polychates. He went so far as to classify ''Wiwaxia'' as a member of a modern [[Order (biology)| order]], [[Phyllodocida]], and pointed out that ''Wiwaxia''’s lack of obvious [[Segmentation (biology)| segmentation]] is no barrier to this, as some modern polychaetes also show no segmentation except during development.<ref name="Butterfield1990" /> He later noted that Wiwaxia lack some polychate features which he would expect to be easily preserved in fossils, and therefore a stem-group [[annelid]], in other words an evolutionary "aunt" of modern annelids.<ref name="Butterfield2003">{{cite journal
| author=Butterfield, N.J. |year=2003
| title=Exceptional Fossil Preservation and the Cambrian Explosion |journal=Integr. Comp. Biol.
|volume=43 | pages=166–177
| url=http://icb.oxfordjournals.org/cgi/content/full/43/1/166#I1540-7063-043-01-0166-BUTTERFIELD
|accessdate=2006-12-02 | doi=10.1093/icb/43.1.166
}}</ref>

<div style="float:right; width:auto; border:solid 1px silver; padding:2px;">
<div style="width:auto; border:solid 1px silver; padding:5px">
{{clade
|1={{clade
|1=[[Mollusca|MOLLUSCA]]
|2={{clade
|1="Siberian [[halkieriid]]"
|2={{clade
|1={{clade
|1={{clade
|1={{clade
|1=[[Annelida|ANNELIDA]]
|2=''[[Canadia]]''
}}
|2=''[[Wiwaxia]]''
}}
|2=''[[Thambetolepis]]''<br />([[halkieriid]])
}}
|2={{clade
|1=''[[Halkieria]] evangelista''
|2=[[Brachiopoda|BRACHIOPODA]]
}}
}}
}}
}}
}}
</div>Cladogram:Conway Morris & Peel (1995)<ref name="ConwayMorrisPeel1995" /></div>
Conway Morris and Peel (1995) largely accepted Butterfield's arguments and treated ''Wiwaxia'' as an ancestor or "aunt" of the polychaetes, and said Butterfield had informed them that the microscopic structure of ''Wiwaxia''’s sclerites was identical to that of the bristles of two Burgess Shale polychaetes ''Burgessochaeta'' and ''Canadia''. Conway Morris and Peel also wrote that one specimen of ''Wiwaxia'' showed traces of a small shell, possibly a vestige left over from an earlier stage in the animal's evolution, and noted that one group of modern polychaetes also has what may be a vestigial shell. However they maintained that ''Wiwaxia''’s feeding aparatus was much more like a molluscan [[radula]]. They also argued that ''Wiwaxia'' was fairly closely related to and in fact descended from the [[halkieriid]]s, as the sclerites are divided into similar groups, although those of halkieriids were much smaller and more numerous; they also said that in 1994 Butterfield had found ''Wiwaxia'' sclerites that were clearly hollow. They presented a large [[cladistics| cladogram]] according to which:<ref name="ConwayMorrisPeel1995">{{ cite journal
| title=Articulated Halkieriids from the Lower Cambrian of North Greenland and their Role in Early Protostome Evolution
| author=Conway Morris, S., and Peel, J. S.
| journal=Philosophical Transactions of the Royal Society: Biological Sciences | volume=347
| issue=1321 | pages=305–358 | doi=10.1098/rstb.1995.0029
| url=http://journals.royalsociety.org/content/32l541667hj3071k/ | accessdate=2008-07-31
| year=1995
}}</ref>
*The earliest [[halkieriid]]s were a "sister" group to the molluscs, in other words descendants of a fairly closely-related common ancestor.
*The halkieriids which Conway Morris had found in Greenland's [[Sirius Passet]] [[lagerstätte]] were a "sister" group to [[brachiopods]], animals whose modern forms have bivalve shells but differ from molluscs in having muscular stalks and a distinctive feeding apparatus, the [[lophophore]].
*Another halkieriid [[genus]], [[Thambetolepis]], was a "great aunt" of annelids and ''Wiwaxia'' was an "aunt" of annelids.<ref name="ConwayMorrisPeel1995" />

Marine biologist Amélie H. Scheltema ''et al'' (2003) argued that ''Wiwaxia''’s feeding apparatus is very similar to the [[radula]]s of some modern shell-less [[aplacophora| aplacophoran]] [[mollusc]]s, and that the sclerites of the two groups are very similar. They concluded that ''Wiwaxia'' was a member of a [[clade]] that includes molluscs.<ref>{{ cite journal
| title=Original Molluscan Radula: Comparisons Among Aplacophora, Polyplacophora, Gastropoda, and the Cambrian Fossil ''Wiwaxia corrugata''
| author=Scheltema, A.H., Kerth, K., and Kuzirian, A.M.
| journal=Journal of Morphology | volume=257 |pages=219–245 | date=2003 | doi= 10.1002/jmor.10121
| url=http://www3.interscience.wiley.com/journal/104528759/abstract?CRETRY=1&SRETRY=0
| accessdate=2008-08-05
}}</ref>

Danish zoologist Danny Eibye-Jacobsen argued in 2004 that ''Wiwaxia'' lacks any characters that would firmly place it as a [[polychaete]] or [[annelid]]. Eibye-Jacobsen regarded bristles as a feature shared by molluscs, annelids and brachiopods. Hence even if ''Wiwaxia''’s sclerites closely resembled bristles, which he doubted, this would not prove that ''Wiwaxia''’s closest relative were annelids. He also pointed out that the very different numbers of sclerites in the various zones of ''Wiwaxia''’s body do not correspond to any reasonable pattern of segmentation; while Eibye-Jacobsen did not think that this alone would prevent classification of ''Wiwaxia'' as a polychaete, he thought it was a serious objection given the lack of other clearly polychaete features. In his opinion there were no strong grounds for classifying ''Wiwaxia'' as a proto-annelid or a proto-mollusc, although he thought the ojections against classification as a proto-annelid were the stronger.<ref name="EibyeJacobsen2004">{{cite journal
| title=A reevaluation of Wiwaxia and the polychaetes of the Burgess Shale
| author=Eibye-Jacobsen, D. | journal=Lethaia | volume=37 | issue=3 | pages=317–335
| month=September | year=2004 |doi=10.1080/00241160410002027
| url=http://www.ingentaconnect.com/content/tandf/slet/2004/00000037/00000003/art00011;jsessionid=383hjtjp6370h.alexandra
| accessdate = 2008-08-04
}}</ref>

Butterfield returned to the debate in 2006, repeating the arguments he presented in 1990 for regarding ''Wiwaxia'' as an early polychaete and adding that, while bristles are a feature of several groups, they appear as a covering over the back only in polychaetes.<ref name=Butterfield2006>{{cite journal
| author = Butterfield, N.J. | year = 2006
| title = Hooking some stem-group ‘‘worms’’: fossil lophotrochozoans in the Burgess Shale
| journal = Bioessays | volume = 28 | issue = 12 | pages = 1161-6 | doi = 10.1002/bies.20507
| url=http://www3.interscience.wiley.com/journal/113471993/abstract?CRETRY=1&SRETRY=0
| accessdate=2008-08-06
}}</ref>

==Gallery==
<gallery>
Image:Wiwaxia.jpg|Fossil specimen of ''Wiwaxia''. White marks were made by dental drill during excavation of the fossil. Dark sclerites are just visible; spines are preserved in orange.
Image:WiwaxiaSpeciman RoyalOntarioMuseum.png|Fossil specimen on display at the [[Royal Ontario Museum]], Toronto.
Image:Wiwaxia_Smithsonian.JPG|Fossil specimen on display at the [[National Museum of Natural History|Smithsonian]] in Washington, DC
</gallery>

==See also==
* [[Coeloscleritophoran]]

==References==
{{reflist}}

==External links==
*[[Pharyngula (blog)|Pharyngula]] [http://scienceblogs.com/pharyngula/2007/03/orthozanclus.php entry] on ''[[Orthrozanclus reburrus]]''

{{portal|Paleontology}}

[[Category:Burgess Shale fossils]]
[[Category:Cambrian animals]]
[[Category:Prehistoric animals]]

[[es:Wiwaxia]]
[[fr:Wiwaxia]]
[[it:Wiwaxia corrugata]]
[[ja:ウィワクシア]]
[[pl:Wiwaxia]]
[[simple:Wiwaxia]]
[[fi:Wiwaxia corrugata]]
[[sv:Wiwaxia]]
[[vo:Wiwaxia]]

Wiwaxia

2009-04-12T15:42:17Z

Jstuby: moved image

{{see|Halwaxiida}}
{{Taxobox
| fossil_range = Early–Middle [[Cambrian]]
| image = Wiwaxia_corrugata.jpg
| regnum = [[Animal]]ia
| superphylum = [[Lophotrochozoa]]
| phylum = ''[[incertae sedis]]
| unranked_classis = [[Halwaxiida]]
| familia = '''Wiwaxiidae'''
| familia_authority = Walcott, 1911
| genus = '''''Wiwaxia'''''
| binomial = ''Wiwaxia corrugata''
| binomial_authority = Walcott, 1911
}}

'''''Wiwaxia''''' is genus of soft-bodied, scale-covered animals known from [[Burgess shale]] type {{lagerstatte}} dating from the Early to Middle Cambrian.<ref name="Zhao1994" /><ref name="ConwayMorris1985" /> The organisms are mainly known from dispersed sclerites; articulated specimens, where found, range from {{convert|3.4|mm|in}} to a little over {{convert|5|cm|in}} in length. The precise taxonomic affinities of the genus are a matter of ongoing debate amongst palaeontologists.

==History of discovery==
''Wiwaxia'' was originally described by W.D. Matthew in 1899 from an isolated spine that had been found earlier in the Ogyopsis Shale, and classified as a [[hyolith]]id.<ref name="ConwayMorris1985" /> Further specimens were found by in 1911 by American [[paleontologist]] [[Charles Doolittle Walcott]] as a result of one of his field trips to the nearby [[Burgess Shale]] in the Canadian [[Rocky Mountains]], and he classified it as a member of the [[polychaete]] group of [[annelid]] worms.<ref name="Walcott1911" />

In 1966 and 1967 a team led by [[Harry B. Whittington]] revisited the Burgess Shale and found so many fossils that it took years to analyze them all, and ''Wiwaxia'' was one of the most difficult to analyze.<ref>{{cite book
| author=[[Stephen Jay Gould| Gould, S.J.]] | title=Wonderful Life | publisher= Hutchinson Radius
| location=London | date=1990 | isbn=0091742714 | pages=77 and p. 189
}}</ref> Eventually in 1985 [[Simon Conway Morris]], then a member of Whittington's team, published a detailed description that concluded ''Wiwaxia'' was not a polychaete.<ref name="ConwayMorris1985">{{cite journal
| author = Conway Morris, S. | year = 1985
| title = The Middle Cambrian metazoan Wiwaxia corrugata (Matthew) from the Burgess Shale and Ogygopsis Shale, British Columbia, Canada
| journal=Philosophical Transactions of the Royal Society of London, Series B
| volume = 307 | pages = 507–582 | doi=10.1098/rstb.1985.0005
| url=http://www.jstor.org/pss/2396338 | accessdate=2008-08-04
}}</ref> All the known specimens came from in and around the Burgess Shale until 1991, when fragmentary fossils were reported from Australia's Georgina Basin.<ref>{{ cite journal
| author=Southgate, P.N., and Shergold, J.H. | date=1991
| title=Application of sequence stratigraphic concepts to Middle Cambrian phosphogenesis, Georgina Basin, Australia
| journal=Journal of Australian Geology and Geophysics | volume=12 | pages=119-144
}}</ref> In 2004 additional finds which may represent two different species were reported from the same area.<ref name="Porter2004HalkieriidsMidCambrianAustralia">{{ cite journal
| author=Porter, S.M. | date=May 2004 | accessdate=2008-08-01
| url=http://findarticles.com/p/articles/mi_qa3790/is_200405/ai_n9377598/pg_1?tag=artBody;col1
| title=Halkieriids in Middle Cambrian Phosphatic Limestones from Australia
| journal=Journal of Paleontology | volume=78 |issue=3 | pages=574-590
| doi=10.1666/0022-3360(2004)078<0574:HIMCPL>2.0.CO;2
}}</ref>

==Occurrence==
Reasonably complete specimens have been found in the [[Burgess Shale]], and fragmentary specimens in in nearby strata slightly older than and younger than the Burgess Shale,<ref name="ConwayMorris1985" /> in [[China]]'s Kaili Formation<ref name="Zhao1994">{{cite journal
| author = Zhao, Y.L. | coauthors = Qian, Y.; Li, X.S.
| year = 1994
| title = Wiwaxia from Early-Middle Cambrian Kaili Formation in Taijiang, Guizhou
| journal = Acta Palaeontologica Sinica | volume = 33 | issue = 3 | pages = 359–366
| url=http://www.jstor.org/pss/1307127 | accessdate=2008-08-04
}}</ref> and in [[Australia]]'s Georgina Basin.<ref name="Porter2004HalkieriidsMidCambrianAustralia" /> All of these locations are dated to the Middle [[Cambrian]] period, and the Burgess Shale has been dated to {{ma|505}}.<ref>{{cite web
| title = Age of Burgess Shale
| url=http://palaeo.gly.bris.ac.uk/palaeofiles/lagerstatten/Burgess/Setting.html
| work = Burgess Shale | publisher = Bristol University | accessdate = 2007-09-05
}}</ref> These finds show that ''Wiwaxia'' and most of the other [[Burgess shale type fauna| Burgess Shale type fauna]] were very widespread.<ref name="Zhao1994" /><ref>{{ cite web
| url=http://paleobiology.si.edu/burgess/cambrianWorld.html | title=The Cambrian World
| accessdate=2008-08-04 }} Reconstruction of the Burgess Shale and map of the world in Mid-Cambrian times.</ref>

==Description==
{| style="float:right; width:300px" | border="0" | cellpadding=3 cellspacing=0"
|-
| {{Annotated image | float=right | caption=''[[Wiwaxia]]'' sclerite zones, seen from front| image=Wiwaxia body zones.png | width=300 | height=110| image-width=150 | image-left=93 | image-top=0
| annotations =
{{Annotation|90|25|Spine}}
{{Annotation|150|40|Dorsal}}
{{Annotation|64|60|Upper lateral}}
{{Annotation|201|70|Lower lateral}}
{{Annotation|63|79|Ventro-lateral}}
{{Annotation|173|96|<span style{{=}}"background-color:#753a00">      </span> {{=}} Frontal}}
}}
|-
| {{Annotated image | float=right | caption=''[[Wiwaxia]]'' viewed from top (moving up) and right| image=Wiwaxia plan n elev.png | width=300 | height=130 image-width=300 | image-left=0 | image-top=0
| annotations =
}}
|}
This concentrates on the species ''Wiwaxia corrugata'', found in the Burgess Shale, since the other specimens consist only of fragments, while the Burgess Shale has provided at least 138 complete ones.<ref name="ConwayMorris1985" /><ref name="Porter2004HalkieriidsMidCambrianAustralia" />

''Wiwaxia'' was a [[bilaterally symmetrical]] animal. Viewed from the top the body was [[elliptical]] with no distinct head or tail, and from the front or rear it was almost [[rectangular]]. The most complete fossils fall into two size ranges: {{convert|2|cm|in}} to {{convert|5|cm|in}} long, which are thought to be adults; and {{convert|3.4|mm|in}} to {{convert|1.5|cm|in}}, which are thought to be juveniles. Estimating their height is difficult because specimens were compressed after death; a specimen of the average length, {{convert|3.4|mm|in}}, may have been {{convert|1|cm|in}} high excluding the spines on their backs. The ratio of width to length does not appear to change as the animals grew.<ref name="ConwayMorris1985" />

The animal was covered in small ribbed armor plates called [[sclerites]], that lay flat against the body, overlapped so that the rear of one covered the front of the one behind, and formed five main regions — the top, with 8-9 rows of sclerites; the upper part of the sides, with 11-12; the lower part of the sides, with 8; the front; and the area nearest the sea-floor, with 12-17 rows.<ref name="EibyeJacobsen2004" /> Most of the sclerites were shaped like oval leaves, but the ventro-lateral ones, nearest the sea-floor, were [[crescent]]-shaped, rather like flattened [[banana]]s, and formed a single row with the tips pointing down. In addition there were two rows of ribbed spines running from to rear, one along each side of the top surface, and projecting out and slightly upwards, with a slight upwards curve near the tips. Specimens ranging from {{convert|11|mm|in}} {{convert|52|mm|in}} have about the same number of ventro-lateral sclerites just above the foot. On the other hand the number of spines seems to depend on the size of the specimen, up to about 12 per side. The number and spacing of the spines is asymmetrical in the specimens found, and this may have been natural rather than a result of events in the animal's life or after death. Although the spines in the middle of each row are usually the longest, up to {{convert|5|cm|in}}, a few specimens have rather short middle spines, perhaps because these were part-grown replacements. The smallest specimens may have lacked the long dorsal spines, which appear to have grown quickly in larger juveniles and then more slowly in adults.<ref name="ConwayMorris1985" />

{{Annotated image | float=right | caption=''[[Wiwaxia]]'' spine, seen from front and side| image=Wiwaxia spines 01.png | width=200 | height=124| image-width=200 | image-left=0 | image-top=0
| annotations =
{{Annotation|80|40|"Blade"}}
{{Annotation|80|100|<span style{{=}}"background-color:#ff8080">      </span> {{=}} Root}}
}}
Each sclerite was rooted separately in the body; the roots of body sclerites are 40% of the external length or a little less, while the roots of the spines are a little over 25% of the external length; all were rooted in pockets in the skin, rather like the [[Hair follicle| follicle]]s of [[mammal]]ian [[hair]]. The roots of the body sclerites were significantly narrower than the sclerites, but the spines had roots about as wide as their bases; both types of root were made of fairly soft tissue. The sclerites and spines were not mineralized, and the frayed appearance of some broken ones suggests a fibrous structure. They way they were preserved suggests they were not made of [[chitin]], from which [[insect]]s' [[exoskeletons]] are formed. They may have been made of [[tanning| tanned]] proteins or of [[collagen]], which is the main component of [[cartilage]]s and [[tendon]]s in humans. Since the body sclerites had bases that were narrower than the hard external parts, it is hard to see how they grew. They may have enclosed soft tissue that could have [[secrete]]d the hard walls, but there is no convincing evidence for this.<ref name="ConwayMorris1985" /> Butterfield (1990) examined some sclerites under both [[Optical microscope| optical]] and [[scanning electron microscope]]s and concluded that they were not hollow, and that the bases split and spread to form the blades, a pattern that is also seen in [[monocot]] leaves.
<ref name="Butterfield1990" />

[[Image:Wiwaxia feeding apparatus 01.png| thumb | right | ''[[Wiwaxia]]'' usually had two tooth-rows: opened for feeding (left); folded (right). In both cases the front of the animal is at the top. ]]
''Wiwaxia''’s flat underside was soft and unarmored. Little is known of the internal anatomy, although the gut apparently ran straight and all the way from the front to the rear. At the the front end of the gut, about {{convert|5|mm|in}} from the animal's front in an average specimen about {{convert|2.5|cm|in}} long, there was a feeding apparatus that consisted of two (or in rare large specimens three) rows of backward-pointing conical teeth. The feeding apparatus was tough enough to be frequently preserved, but unmineralized and fairly flexible, as it folded and retracted when not in use. It would have had to pushed forward out of the mouth in order to feed. Even the smallest specimens have this type of apparatus, with two rows containing the same number of teeth as in larger ones. This indicates that ''Wiwaxia''’s feeding habits remained the same throughout its life after the [[larva]]l stage. The feeding apparatus may have acted as a [[rasp]] to scrape [[bacteria]] off the top of the [[microbial mat]] that covered the sea-floor, or as a [[Rake (tool)| rake]] to gather food particles that lay on the sea-floor.<ref name="ConwayMorris1985" />

Since there is no sign of eyes or tentacles, ''Wiwaxia'' may have relied mainly on chemical senses such as smell and taste. Its [[respiratory]] system is also unknown.<ref name="ConwayMorris1985" />

[[Image:WiwaxiaSpeciman RoyalOntarioMuseum.png|thumb|right|A specimen of Wiwaxia, on display at the [[Royal Ontario Museum]], Toronto.]]
One juvenile specimen appears to be preserved while [[molt]]ing and not yet completely detached from its discarded armor. Its new set of spines seem less rigid than the old ones and slightly underdeveloped, as if the next stages were going to be inflated by body fluids and then hardening. The new armor may have had an internal volume 50% to 70% larger than the old one. Molting appears to have occurred all at once, as adult specimens shows no signs of interruptions in the sclerite armor that would indicate molting of parts of the armor or of individual sclerites. Since the bases of the body sclerites are relatively narrow and these is no sign of sclerites splitting during molting, withdrawing soft tissue from the old sclerites would probably have required the tissues to be broken down in to a more fluid form, as happens in the claws of lobsters and crabs when they molt. The skin must also have been shed, since the discarded armor appears as a complete unit rather than scattered sclerites. In the juvenile that was apparently molting when it died, the feeding apparatus also appears to have been shed, as half of one tooth row is pointing forwards.<ref name="ConwayMorris1985" />

The long dorsal spines may have been a defense against predators, and finds of broken spines suggest that ''Wiwaxia'' was attacked. The animal appears to have crawled on the surface of the sea-floor feeding on particles that fell from higher levels of the sea. ''Wiwaxia'' shows no signs of legs and was probably too large to move on [[cilia]], so it probably moved by muscular contraction that made its foot ripple. Juveniles may have burrowed into the sea-floor. In one specimen a small [[brachiopod]], ''[[Diraphora]] bellicostata'', appears to be attached to one of the ventro-lateral sclerites. This suggests that adult ''Wiwaxia'' did not burrow or even plough much into the sea-floor as they moved. Two other specimens of ''[[Diraphora]] bellicostata'' have been found attached to dorsal sclerites. ''Wiwaxia'' appears to have been solitary rather than gregarious.<ref name="ConwayMorris1985" />
[[Image:Wiwaxia_Smithsonian.JPG|thumb|right|Fossil specimen on display at the [[National Museum of Natural History|Smithsonian]] in Washington, DC]]
==Classification==
[[Image:Wiwaxia.jpg|thumb|A typical specimen of ''Wiwaxia''. White marks were made by dental drill during excavation of the fossil. Dark sclerites are just visible; spines are preserved in orange.]]
During the Cambrian, most of the [[phylum|main groupings of animals]] recognised today were beginning to diverge. Consequently, many lineages (that would later become extinct) appear intermediate to two more more modern groups, or lack features common to all modern members of a group, and hence fall into the "[[stem group]]" of a modern [[taxon]].<ref>{{ cite journal
| author=Budd, G.E. | title=The Cambrian Fossil Record and the Origin of the Phyla
| journal=Integrative and Comparative Biology | date=2003 | volume=43 | issue=1 | pages=157-165
| doi=10.1093/icb/43.1.157 | url=http://icb.oxfordjournals.org/cgi/content/full/43/1/157
| accessdate= 2006-08-20
}}</ref> Debate is ongoing as to whether ''Wiwaxia'' can be placed within a modern crown group and, if it cannot, in which group's stem it falls. When Walcott first described ''Wiwaxia'', he regarded it as a [[polychaete]] [[annelid]] worm, and its [[sclerite]]s as similar to the [[elytra]] ("scales") of annelids.<ref name=Walcott1911>{{cite journal
| author = Walcott, C.D. | authorlink = Charles Doolittle Walcott | year = 1911
| title = Middle Cambrian annelids. Cambrian geology and paleontology, II
| journal = Smithsonian Miscellaneous Collections | volume = 57 | pages = 109–144
}}</ref> More recently the debate has been intense, and proposed classifications include: a member of an extinct [[phylum]] distantly related to the molluscs; a crown-group polychaete; a stem-group annelid; a problematic bilaterian; a stem- or possibly primitive crown-group mollusc.<ref name="Butterfield2006" />

In 1985 [[Simon Conway Morris]] agreed that there were similarities to polychaetes, but considered that ''Wiwaxia''’s sclerites were different in construction to annelids' elytra. He was more impressed by the similarites between ''Wiwaxia''’s feeding apparatus and a [[mollusc]]an [[radula]], and assigned the animal to a new taxon Molluscata, which he proposed should also contain the molluscs and [[Hyolitha| hyolithid]]s.<ref name="ConwayMorris1985" /> When he later described the first fairly complete specimens of ''[[Halkieria]]'', he suggested that these were closely related to ''Wiwaxia''.<ref name="ConwayMorrisPeel1990">{{ cite journal
| title=Articulated halkieriids from the Lower Cambrian of north Greenland
| author=Conway Morris, S., and Peel, J.S. | journal=Nature | volume=345 | pages=802–805
| date=June 1990 | doi=10.1038/345802a0
| url=http://www.nature.com/nature/journal/v345/n6278/abs/345802a0.html | accessdate=2008-07-31
}} A short but free account is given at {{ cite web |
| url=http://www.stephenjaygould.org/library/naturalhistory_cambrian.html
| title=Showdown on the Burgess Shale | accessdate=2008-07-31
}}</ref>

Nick Butterfield, then a postgraduate paleontologist at Harvard inspired by [[Stephen Jay Gould]]'s lectures, agreed that the sclerites were not like elytra, which are relatively fleshy and soft. However, since the sclerites were solid, he concluded that ''Wiwaxia'' could not be a member of the "Coeloscleritophora", a [[taxon]] that had been proposed in order to unite organisms with hollow sclerites, and could not be closely related to the [[halkieriid]]s, which have hollow sclerites. Instead he thought that they were very similar in several ways to the
[[chitin]]ous bristles ([[setae]]) that project from the bodies of modern annelids and in some [[genus| genera]] form leaf-like scales that cover the back like roof tiles - in composition, in detailed structure, in how they were attached to the body via "[[Hair follicle|follicle]]s" and in overall appearance. Some modern annelids also develop on each side rows of longer bristles, which both Walcott and Butterfield considered similar to ''Wiwaxia''’s dorsal spines.<ref name="Butterfield1990">{{cite journal
| author=Butterfield, N.J. | year=1990
| title=A reassessment of the enigmatic Burgess Shale fossil ''Wiwaxia corrugata'' (Matthew) and its relationship to the polychaete ''Canadia spinosa''. Walcott
| journal=Paleobiology | volume=16 | pages=287–303
| url=http://www.jstor.org/stable/2400789 | accessdate=2008-08-05
}}</ref> including the [[halkieriid]]s.

Butterfield also contended that ''Wiwaxia''’s feeding apparatus, instead of being mounted in the middle of its "head", was just as likely to be mounted in two parts on the sides of the "head", an arrangement that is common in polychates. He went so far as to classify ''Wiwaxia'' as a member of a modern [[Order (biology)| order]], [[Phyllodocida]], and pointed out that ''Wiwaxia''’s lack of obvious [[Segmentation (biology)| segmentation]] is no barrier to this, as some modern polychaetes also show no segmentation except during development.<ref name="Butterfield1990" /> He later noted that Wiwaxia lack some polychate features which he would expect to be easily preserved in fossils, and therefore a stem-group [[annelid]], in other words an evolutionary "aunt" of modern annelids.<ref name="Butterfield2003">{{cite journal
| author=Butterfield, N.J. |year=2003
| title=Exceptional Fossil Preservation and the Cambrian Explosion |journal=Integr. Comp. Biol.
|volume=43 | pages=166–177
| url=http://icb.oxfordjournals.org/cgi/content/full/43/1/166#I1540-7063-043-01-0166-BUTTERFIELD
|accessdate=2006-12-02 | doi=10.1093/icb/43.1.166
}}</ref>

<div style="float:right; width:auto; border:solid 1px silver; padding:2px;">
<div style="width:auto; border:solid 1px silver; padding:5px">
{{clade
|1={{clade
|1=[[Mollusca|MOLLUSCA]]
|2={{clade
|1="Siberian [[halkieriid]]"
|2={{clade
|1={{clade
|1={{clade
|1={{clade
|1=[[Annelida|ANNELIDA]]
|2=''[[Canadia]]''
}}
|2=''[[Wiwaxia]]''
}}
|2=''[[Thambetolepis]]''<br />([[halkieriid]])
}}
|2={{clade
|1=''[[Halkieria]] evangelista''
|2=[[Brachiopoda|BRACHIOPODA]]
}}
}}
}}
}}
}}
</div>Cladogram:Conway Morris & Peel (1995)<ref name="ConwayMorrisPeel1995" /></div>
Conway Morris and Peel (1995) largely accepted Butterfield's arguments and treated ''Wiwaxia'' as an ancestor or "aunt" of the polychaetes, and said Butterfield had informed them that the microscopic structure of ''Wiwaxia''’s sclerites was identical to that of the bristles of two Burgess Shale polychaetes ''Burgessochaeta'' and ''Canadia''. Conway Morris and Peel also wrote that one specimen of ''Wiwaxia'' showed traces of a small shell, possibly a vestige left over from an earlier stage in the animal's evolution, and noted that one group of modern polychaetes also has what may be a vestigial shell. However they maintained that ''Wiwaxia''’s feeding aparatus was much more like a molluscan [[radula]]. They also argued that ''Wiwaxia'' was fairly closely related to and in fact descended from the [[halkieriid]]s, as the sclerites are divided into similar groups, although those of halkieriids were much smaller and more numerous; they also said that in 1994 Butterfield had found ''Wiwaxia'' sclerites that were clearly hollow. They presented a large [[cladistics| cladogram]] according to which:<ref name="ConwayMorrisPeel1995">{{ cite journal
| title=Articulated Halkieriids from the Lower Cambrian of North Greenland and their Role in Early Protostome Evolution
| author=Conway Morris, S., and Peel, J. S.
| journal=Philosophical Transactions of the Royal Society: Biological Sciences | volume=347
| issue=1321 | pages=305–358 | doi=10.1098/rstb.1995.0029
| url=http://journals.royalsociety.org/content/32l541667hj3071k/ | accessdate=2008-07-31
| year=1995
}}</ref>
*The earliest [[halkieriid]]s were a "sister" group to the molluscs, in other words descendants of a fairly closely-related common ancestor.
*The halkieriids which Conway Morris had found in Greenland's [[Sirius Passet]] [[lagerstätte]] were a "sister" group to [[brachiopods]], animals whose modern forms have bivalve shells but differ from molluscs in having muscular stalks and a distinctive feeding apparatus, the [[lophophore]].
*Another halkieriid [[genus]], [[Thambetolepis]], was a "great aunt" of annelids and ''Wiwaxia'' was an "aunt" of annelids.<ref name="ConwayMorrisPeel1995" />

Marine biologist Amélie H. Scheltema ''et al'' (2003) argued that ''Wiwaxia''’s feeding apparatus is very similar to the [[radula]]s of some modern shell-less [[aplacophora| aplacophoran]] [[mollusc]]s, and that the sclerites of the two groups are very similar. They concluded that ''Wiwaxia'' was a member of a [[clade]] that includes molluscs.<ref>{{ cite journal
| title=Original Molluscan Radula: Comparisons Among Aplacophora, Polyplacophora, Gastropoda, and the Cambrian Fossil ''Wiwaxia corrugata''
| author=Scheltema, A.H., Kerth, K., and Kuzirian, A.M.
| journal=Journal of Morphology | volume=257 |pages=219–245 | date=2003 | doi= 10.1002/jmor.10121
| url=http://www3.interscience.wiley.com/journal/104528759/abstract?CRETRY=1&SRETRY=0
| accessdate=2008-08-05
}}</ref>

Danish zoologist Danny Eibye-Jacobsen argued in 2004 that ''Wiwaxia'' lacks any characters that would firmly place it as a [[polychaete]] or [[annelid]]. Eibye-Jacobsen regarded bristles as a feature shared by molluscs, annelids and brachiopods. Hence even if ''Wiwaxia''’s sclerites closely resembled bristles, which he doubted, this would not prove that ''Wiwaxia''’s closest relative were annelids. He also pointed out that the very different numbers of sclerites in the various zones of ''Wiwaxia''’s body do not correspond to any reasonable pattern of segmentation; while Eibye-Jacobsen did not think that this alone would prevent classification of ''Wiwaxia'' as a polychaete, he thought it was a serious objection given the lack of other clearly polychaete features. In his opinion there were no strong grounds for classifying ''Wiwaxia'' as a proto-annelid or a proto-mollusc, although he thought the ojections against classification as a proto-annelid were the stronger.<ref name="EibyeJacobsen2004">{{cite journal
| title=A reevaluation of Wiwaxia and the polychaetes of the Burgess Shale
| author=Eibye-Jacobsen, D. | journal=Lethaia | volume=37 | issue=3 | pages=317–335
| month=September | year=2004 |doi=10.1080/00241160410002027
| url=http://www.ingentaconnect.com/content/tandf/slet/2004/00000037/00000003/art00011;jsessionid=383hjtjp6370h.alexandra
| accessdate = 2008-08-04
}}</ref>

Butterfield returned to the debate in 2006, repeating the arguments he presented in 1990 for regarding ''Wiwaxia'' as an early polychaete and adding that, while bristles are a feature of several groups, they appear as a covering over the back only in polychaetes.<ref name=Butterfield2006>{{cite journal
| author = Butterfield, N.J. | year = 2006
| title = Hooking some stem-group ‘‘worms’’: fossil lophotrochozoans in the Burgess Shale
| journal = Bioessays | volume = 28 | issue = 12 | pages = 1161-6 | doi = 10.1002/bies.20507
| url=http://www3.interscience.wiley.com/journal/113471993/abstract?CRETRY=1&SRETRY=0
| accessdate=2008-08-06
}}</ref>

==See also==
* [[Coeloscleritophoran]]

==References==
{{reflist}}

==External links==
*[[Pharyngula (blog)|Pharyngula]] [http://scienceblogs.com/pharyngula/2007/03/orthozanclus.php entry] on ''[[Orthrozanclus reburrus]]''

{{portal|Paleontology}}

[[Category:Burgess Shale fossils]]
[[Category:Cambrian animals]]
[[Category:Prehistoric animals]]

[[es:Wiwaxia]]
[[fr:Wiwaxia]]
[[it:Wiwaxia corrugata]]
[[ja:ウィワクシア]]
[[pl:Wiwaxia]]
[[simple:Wiwaxia]]
[[fi:Wiwaxia corrugata]]
[[sv:Wiwaxia]]
[[vo:Wiwaxia]]

Wiwaxia

2009-04-12T15:38:41Z

Jstuby: added image of fossil from Smithsonian

{{see|Halwaxiida}}
{{Taxobox
| fossil_range = Early–Middle [[Cambrian]]
| image = Wiwaxia_corrugata.jpg
| regnum = [[Animal]]ia
| superphylum = [[Lophotrochozoa]]
| phylum = ''[[incertae sedis]]
| unranked_classis = [[Halwaxiida]]
| familia = '''Wiwaxiidae'''
| familia_authority = Walcott, 1911
| genus = '''''Wiwaxia'''''
| binomial = ''Wiwaxia corrugata''
| binomial_authority = Walcott, 1911
}}

'''''Wiwaxia''''' is genus of soft-bodied, scale-covered animals known from [[Burgess shale]] type {{lagerstatte}} dating from the Early to Middle Cambrian.<ref name="Zhao1994" /><ref name="ConwayMorris1985" /> The organisms are mainly known from dispersed sclerites; articulated specimens, where found, range from {{convert|3.4|mm|in}} to a little over {{convert|5|cm|in}} in length. The precise taxonomic affinities of the genus are a matter of ongoing debate amongst palaeontologists.

==History of discovery==
''Wiwaxia'' was originally described by W.D. Matthew in 1899 from an isolated spine that had been found earlier in the Ogyopsis Shale, and classified as a [[hyolith]]id.<ref name="ConwayMorris1985" /> Further specimens were found by in 1911 by American [[paleontologist]] [[Charles Doolittle Walcott]] as a result of one of his field trips to the nearby [[Burgess Shale]] in the Canadian [[Rocky Mountains]], and he classified it as a member of the [[polychaete]] group of [[annelid]] worms.<ref name="Walcott1911" />

In 1966 and 1967 a team led by [[Harry B. Whittington]] revisited the Burgess Shale and found so many fossils that it took years to analyze them all, and ''Wiwaxia'' was one of the most difficult to analyze.<ref>{{cite book
| author=[[Stephen Jay Gould| Gould, S.J.]] | title=Wonderful Life | publisher= Hutchinson Radius
| location=London | date=1990 | isbn=0091742714 | pages=77 and p. 189
}}</ref> Eventually in 1985 [[Simon Conway Morris]], then a member of Whittington's team, published a detailed description that concluded ''Wiwaxia'' was not a polychaete.<ref name="ConwayMorris1985">{{cite journal
| author = Conway Morris, S. | year = 1985
| title = The Middle Cambrian metazoan Wiwaxia corrugata (Matthew) from the Burgess Shale and Ogygopsis Shale, British Columbia, Canada
| journal=Philosophical Transactions of the Royal Society of London, Series B
| volume = 307 | pages = 507–582 | doi=10.1098/rstb.1985.0005
| url=http://www.jstor.org/pss/2396338 | accessdate=2008-08-04
}}</ref> All the known specimens came from in and around the Burgess Shale until 1991, when fragmentary fossils were reported from Australia's Georgina Basin.<ref>{{ cite journal
| author=Southgate, P.N., and Shergold, J.H. | date=1991
| title=Application of sequence stratigraphic concepts to Middle Cambrian phosphogenesis, Georgina Basin, Australia
| journal=Journal of Australian Geology and Geophysics | volume=12 | pages=119-144
}}</ref> In 2004 additional finds which may represent two different species were reported from the same area.<ref name="Porter2004HalkieriidsMidCambrianAustralia">{{ cite journal
| author=Porter, S.M. | date=May 2004 | accessdate=2008-08-01
| url=http://findarticles.com/p/articles/mi_qa3790/is_200405/ai_n9377598/pg_1?tag=artBody;col1
| title=Halkieriids in Middle Cambrian Phosphatic Limestones from Australia
| journal=Journal of Paleontology | volume=78 |issue=3 | pages=574-590
| doi=10.1666/0022-3360(2004)078<0574:HIMCPL>2.0.CO;2
}}</ref>

==Occurrence==
Reasonably complete specimens have been found in the [[Burgess Shale]], and fragmentary specimens in in nearby strata slightly older than and younger than the Burgess Shale,<ref name="ConwayMorris1985" /> in [[China]]'s Kaili Formation<ref name="Zhao1994">{{cite journal
| author = Zhao, Y.L. | coauthors = Qian, Y.; Li, X.S.
| year = 1994
| title = Wiwaxia from Early-Middle Cambrian Kaili Formation in Taijiang, Guizhou
| journal = Acta Palaeontologica Sinica | volume = 33 | issue = 3 | pages = 359–366
| url=http://www.jstor.org/pss/1307127 | accessdate=2008-08-04
}}</ref> and in [[Australia]]'s Georgina Basin.<ref name="Porter2004HalkieriidsMidCambrianAustralia" /> All of these locations are dated to the Middle [[Cambrian]] period, and the Burgess Shale has been dated to {{ma|505}}.<ref>{{cite web
| title = Age of Burgess Shale
| url=http://palaeo.gly.bris.ac.uk/palaeofiles/lagerstatten/Burgess/Setting.html
| work = Burgess Shale | publisher = Bristol University | accessdate = 2007-09-05
}}</ref> These finds show that ''Wiwaxia'' and most of the other [[Burgess shale type fauna| Burgess Shale type fauna]] were very widespread.<ref name="Zhao1994" /><ref>{{ cite web
| url=http://paleobiology.si.edu/burgess/cambrianWorld.html | title=The Cambrian World
| accessdate=2008-08-04 }} Reconstruction of the Burgess Shale and map of the world in Mid-Cambrian times.</ref>

==Description==
{| style="float:right; width:300px" | border="0" | cellpadding=3 cellspacing=0"
|-
| {{Annotated image | float=right | caption=''[[Wiwaxia]]'' sclerite zones, seen from front| image=Wiwaxia body zones.png | width=300 | height=110| image-width=150 | image-left=93 | image-top=0
| annotations =
{{Annotation|90|25|Spine}}
{{Annotation|150|40|Dorsal}}
{{Annotation|64|60|Upper lateral}}
{{Annotation|201|70|Lower lateral}}
{{Annotation|63|79|Ventro-lateral}}
{{Annotation|173|96|<span style{{=}}"background-color:#753a00">      </span> {{=}} Frontal}}
}}
|-
| {{Annotated image | float=right | caption=''[[Wiwaxia]]'' viewed from top (moving up) and right| image=Wiwaxia plan n elev.png | width=300 | height=130 image-width=300 | image-left=0 | image-top=0
| annotations =
}}
|}
This concentrates on the species ''Wiwaxia corrugata'', found in the Burgess Shale, since the other specimens consist only of fragments, while the Burgess Shale has provided at least 138 complete ones.<ref name="ConwayMorris1985" /><ref name="Porter2004HalkieriidsMidCambrianAustralia" />

''Wiwaxia'' was a [[bilaterally symmetrical]] animal. Viewed from the top the body was [[elliptical]] with no distinct head or tail, and from the front or rear it was almost [[rectangular]]. The most complete fossils fall into two size ranges: {{convert|2|cm|in}} to {{convert|5|cm|in}} long, which are thought to be adults; and {{convert|3.4|mm|in}} to {{convert|1.5|cm|in}}, which are thought to be juveniles. Estimating their height is difficult because specimens were compressed after death; a specimen of the average length, {{convert|3.4|mm|in}}, may have been {{convert|1|cm|in}} high excluding the spines on their backs. The ratio of width to length does not appear to change as the animals grew.<ref name="ConwayMorris1985" />

The animal was covered in small ribbed armor plates called [[sclerites]], that lay flat against the body, overlapped so that the rear of one covered the front of the one behind, and formed five main regions — the top, with 8-9 rows of sclerites; the upper part of the sides, with 11-12; the lower part of the sides, with 8; the front; and the area nearest the sea-floor, with 12-17 rows.<ref name="EibyeJacobsen2004" /> Most of the sclerites were shaped like oval leaves, but the ventro-lateral ones, nearest the sea-floor, were [[crescent]]-shaped, rather like flattened [[banana]]s, and formed a single row with the tips pointing down. In addition there were two rows of ribbed spines running from to rear, one along each side of the top surface, and projecting out and slightly upwards, with a slight upwards curve near the tips. Specimens ranging from {{convert|11|mm|in}} {{convert|52|mm|in}} have about the same number of ventro-lateral sclerites just above the foot. On the other hand the number of spines seems to depend on the size of the specimen, up to about 12 per side. The number and spacing of the spines is asymmetrical in the specimens found, and this may have been natural rather than a result of events in the animal's life or after death. Although the spines in the middle of each row are usually the longest, up to {{convert|5|cm|in}}, a few specimens have rather short middle spines, perhaps because these were part-grown replacements. The smallest specimens may have lacked the long dorsal spines, which appear to have grown quickly in larger juveniles and then more slowly in adults.<ref name="ConwayMorris1985" />

{{Annotated image | float=right | caption=''[[Wiwaxia]]'' spine, seen from front and side| image=Wiwaxia spines 01.png | width=200 | height=124| image-width=200 | image-left=0 | image-top=0
| annotations =
{{Annotation|80|40|"Blade"}}
{{Annotation|80|100|<span style{{=}}"background-color:#ff8080">      </span> {{=}} Root}}
}}
Each sclerite was rooted separately in the body; the roots of body sclerites are 40% of the external length or a little less, while the roots of the spines are a little over 25% of the external length; all were rooted in pockets in the skin, rather like the [[Hair follicle| follicle]]s of [[mammal]]ian [[hair]]. The roots of the body sclerites were significantly narrower than the sclerites, but the spines had roots about as wide as their bases; both types of root were made of fairly soft tissue. The sclerites and spines were not mineralized, and the frayed appearance of some broken ones suggests a fibrous structure. They way they were preserved suggests they were not made of [[chitin]], from which [[insect]]s' [[exoskeletons]] are formed. They may have been made of [[tanning| tanned]] proteins or of [[collagen]], which is the main component of [[cartilage]]s and [[tendon]]s in humans. Since the body sclerites had bases that were narrower than the hard external parts, it is hard to see how they grew. They may have enclosed soft tissue that could have [[secrete]]d the hard walls, but there is no convincing evidence for this.<ref name="ConwayMorris1985" /> Butterfield (1990) examined some sclerites under both [[Optical microscope| optical]] and [[scanning electron microscope]]s and concluded that they were not hollow, and that the bases split and spread to form the blades, a pattern that is also seen in [[monocot]] leaves.
<ref name="Butterfield1990" />

[[Image:Wiwaxia feeding apparatus 01.png| thumb | right | ''[[Wiwaxia]]'' usually had two tooth-rows: opened for feeding (left); folded (right). In both cases the front of the animal is at the top. ]]
''Wiwaxia''’s flat underside was soft and unarmored. Little is known of the internal anatomy, although the gut apparently ran straight and all the way from the front to the rear. At the the front end of the gut, about {{convert|5|mm|in}} from the animal's front in an average specimen about {{convert|2.5|cm|in}} long, there was a feeding apparatus that consisted of two (or in rare large specimens three) rows of backward-pointing conical teeth. The feeding apparatus was tough enough to be frequently preserved, but unmineralized and fairly flexible, as it folded and retracted when not in use. It would have had to pushed forward out of the mouth in order to feed. Even the smallest specimens have this type of apparatus, with two rows containing the same number of teeth as in larger ones. This indicates that ''Wiwaxia''’s feeding habits remained the same throughout its life after the [[larva]]l stage. The feeding apparatus may have acted as a [[rasp]] to scrape [[bacteria]] off the top of the [[microbial mat]] that covered the sea-floor, or as a [[Rake (tool)| rake]] to gather food particles that lay on the sea-floor.<ref name="ConwayMorris1985" />

Since there is no sign of eyes or tentacles, ''Wiwaxia'' may have relied mainly on chemical senses such as smell and taste. Its [[respiratory]] system is also unknown.<ref name="ConwayMorris1985" />

[[Image:WiwaxiaSpeciman RoyalOntarioMuseum.png|thumb|right|A specimen of Wiwaxia, on display at the [[Royal Ontario Museum]], Toronto.]]
One juvenile specimen appears to be preserved while [[molt]]ing and not yet completely detached from its discarded armor. Its new set of spines seem less rigid than the old ones and slightly underdeveloped, as if the next stages were going to be inflated by body fluids and then hardening. The new armor may have had an internal volume 50% to 70% larger than the old one. Molting appears to have occurred all at once, as adult specimens shows no signs of interruptions in the sclerite armor that would indicate molting of parts of the armor or of individual sclerites. Since the bases of the body sclerites are relatively narrow and these is no sign of sclerites splitting during molting, withdrawing soft tissue from the old sclerites would probably have required the tissues to be broken down in to a more fluid form, as happens in the claws of lobsters and crabs when they molt. The skin must also have been shed, since the discarded armor appears as a complete unit rather than scattered sclerites. In the juvenile that was apparently molting when it died, the feeding apparatus also appears to have been shed, as half of one tooth row is pointing forwards.<ref name="ConwayMorris1985" />

The long dorsal spines may have been a defense against predators, and finds of broken spines suggest that ''Wiwaxia'' was attacked. The animal appears to have crawled on the surface of the sea-floor feeding on particles that fell from higher levels of the sea. ''Wiwaxia'' shows no signs of legs and was probably too large to move on [[cilia]], so it probably moved by muscular contraction that made its foot ripple. Juveniles may have burrowed into the sea-floor. In one specimen a small [[brachiopod]], ''[[Diraphora]] bellicostata'', appears to be attached to one of the ventro-lateral sclerites. This suggests that adult ''Wiwaxia'' did not burrow or even plough much into the sea-floor as they moved. Two other specimens of ''[[Diraphora]] bellicostata'' have been found attached to dorsal sclerites. ''Wiwaxia'' appears to have been solitary rather than gregarious.<ref name="ConwayMorris1985" />

==Classification==
[[Image:Wiwaxia.jpg|thumb|A typical specimen of ''Wiwaxia''. White marks were made by dental drill during excavation of the fossil. Dark sclerites are just visible; spines are preserved in orange.]]
During the Cambrian, most of the [[phylum|main groupings of animals]] recognised today were beginning to diverge. Consequently, many lineages (that would later become extinct) appear intermediate to two more more modern groups, or lack features common to all modern members of a group, and hence fall into the "[[stem group]]" of a modern [[taxon]].<ref>{{ cite journal
| author=Budd, G.E. | title=The Cambrian Fossil Record and the Origin of the Phyla
| journal=Integrative and Comparative Biology | date=2003 | volume=43 | issue=1 | pages=157-165
| doi=10.1093/icb/43.1.157 | url=http://icb.oxfordjournals.org/cgi/content/full/43/1/157
| accessdate= 2006-08-20
}}</ref> Debate is ongoing as to whether ''Wiwaxia'' can be placed within a modern crown group and, if it cannot, in which group's stem it falls. When Walcott first described ''Wiwaxia'', he regarded it as a [[polychaete]] [[annelid]] worm, and its [[sclerite]]s as similar to the [[elytra]] ("scales") of annelids.<ref name=Walcott1911>{{cite journal
| author = Walcott, C.D. | authorlink = Charles Doolittle Walcott | year = 1911
| title = Middle Cambrian annelids. Cambrian geology and paleontology, II
| journal = Smithsonian Miscellaneous Collections | volume = 57 | pages = 109–144
}}</ref> More recently the debate has been intense, and proposed classifications include: a member of an extinct [[phylum]] distantly related to the molluscs; a crown-group polychaete; a stem-group annelid; a problematic bilaterian; a stem- or possibly primitive crown-group mollusc.<ref name="Butterfield2006" />

In 1985 [[Simon Conway Morris]] agreed that there were similarities to polychaetes, but considered that ''Wiwaxia''’s sclerites were different in construction to annelids' elytra. He was more impressed by the similarites between ''Wiwaxia''’s feeding apparatus and a [[mollusc]]an [[radula]], and assigned the animal to a new taxon Molluscata, which he proposed should also contain the molluscs and [[Hyolitha| hyolithid]]s.<ref name="ConwayMorris1985" /> When he later described the first fairly complete specimens of ''[[Halkieria]]'', he suggested that these were closely related to ''Wiwaxia''.<ref name="ConwayMorrisPeel1990">{{ cite journal
| title=Articulated halkieriids from the Lower Cambrian of north Greenland
| author=Conway Morris, S., and Peel, J.S. | journal=Nature | volume=345 | pages=802–805
| date=June 1990 | doi=10.1038/345802a0
| url=http://www.nature.com/nature/journal/v345/n6278/abs/345802a0.html | accessdate=2008-07-31
}} A short but free account is given at {{ cite web |
| url=http://www.stephenjaygould.org/library/naturalhistory_cambrian.html
| title=Showdown on the Burgess Shale | accessdate=2008-07-31
}}</ref>

Nick Butterfield, then a postgraduate paleontologist at Harvard inspired by [[Stephen Jay Gould]]'s lectures, agreed that the sclerites were not like elytra, which are relatively fleshy and soft. However, since the sclerites were solid, he concluded that ''Wiwaxia'' could not be a member of the "Coeloscleritophora", a [[taxon]] that had been proposed in order to unite organisms with hollow sclerites, and could not be closely related to the [[halkieriid]]s, which have hollow sclerites. Instead he thought that they were very similar in several ways to the
[[chitin]]ous bristles ([[setae]]) that project from the bodies of modern annelids and in some [[genus| genera]] form leaf-like scales that cover the back like roof tiles - in composition, in detailed structure, in how they were attached to the body via "[[Hair follicle|follicle]]s" and in overall appearance. Some modern annelids also develop on each side rows of longer bristles, which both Walcott and Butterfield considered similar to ''Wiwaxia''’s dorsal spines.<ref name="Butterfield1990">{{cite journal
| author=Butterfield, N.J. | year=1990
| title=A reassessment of the enigmatic Burgess Shale fossil ''Wiwaxia corrugata'' (Matthew) and its relationship to the polychaete ''Canadia spinosa''. Walcott
| journal=Paleobiology | volume=16 | pages=287–303
| url=http://www.jstor.org/stable/2400789 | accessdate=2008-08-05
}}</ref> including the [[halkieriid]]s.

Butterfield also contended that ''Wiwaxia''’s feeding apparatus, instead of being mounted in the middle of its "head", was just as likely to be mounted in two parts on the sides of the "head", an arrangement that is common in polychates. He went so far as to classify ''Wiwaxia'' as a member of a modern [[Order (biology)| order]], [[Phyllodocida]], and pointed out that ''Wiwaxia''’s lack of obvious [[Segmentation (biology)| segmentation]] is no barrier to this, as some modern polychaetes also show no segmentation except during development.<ref name="Butterfield1990" /> He later noted that Wiwaxia lack some polychate features which he would expect to be easily preserved in fossils, and therefore a stem-group [[annelid]], in other words an evolutionary "aunt" of modern annelids.<ref name="Butterfield2003">{{cite journal
| author=Butterfield, N.J. |year=2003
| title=Exceptional Fossil Preservation and the Cambrian Explosion |journal=Integr. Comp. Biol.
|volume=43 | pages=166–177
| url=http://icb.oxfordjournals.org/cgi/content/full/43/1/166#I1540-7063-043-01-0166-BUTTERFIELD
|accessdate=2006-12-02 | doi=10.1093/icb/43.1.166
}}</ref>

<div style="float:right; width:auto; border:solid 1px silver; padding:2px;">
<div style="width:auto; border:solid 1px silver; padding:5px">
{{clade
|1={{clade
|1=[[Mollusca|MOLLUSCA]]
|2={{clade
|1="Siberian [[halkieriid]]"
|2={{clade
|1={{clade
|1={{clade
|1={{clade
|1=[[Annelida|ANNELIDA]]
|2=''[[Canadia]]''
}}
|2=''[[Wiwaxia]]''
}}
|2=''[[Thambetolepis]]''<br />([[halkieriid]])
}}
|2={{clade
|1=''[[Halkieria]] evangelista''
|2=[[Brachiopoda|BRACHIOPODA]]
}}
}}
}}
}}
}}
</div>Cladogram:Conway Morris & Peel (1995)<ref name="ConwayMorrisPeel1995" /></div>
Conway Morris and Peel (1995) largely accepted Butterfield's arguments and treated ''Wiwaxia'' as an ancestor or "aunt" of the polychaetes, and said Butterfield had informed them that the microscopic structure of ''Wiwaxia''’s sclerites was identical to that of the bristles of two Burgess Shale polychaetes ''Burgessochaeta'' and ''Canadia''. Conway Morris and Peel also wrote that one specimen of ''Wiwaxia'' showed traces of a small shell, possibly a vestige left over from an earlier stage in the animal's evolution, and noted that one group of modern polychaetes also has what may be a vestigial shell. However they maintained that ''Wiwaxia''’s feeding aparatus was much more like a molluscan [[radula]]. They also argued that ''Wiwaxia'' was fairly closely related to and in fact descended from the [[halkieriid]]s, as the sclerites are divided into similar groups, although those of halkieriids were much smaller and more numerous; they also said that in 1994 Butterfield had found ''Wiwaxia'' sclerites that were clearly hollow. They presented a large [[cladistics| cladogram]] according to which:<ref name="ConwayMorrisPeel1995">{{ cite journal
| title=Articulated Halkieriids from the Lower Cambrian of North Greenland and their Role in Early Protostome Evolution
| author=Conway Morris, S., and Peel, J. S.
| journal=Philosophical Transactions of the Royal Society: Biological Sciences | volume=347
| issue=1321 | pages=305–358 | doi=10.1098/rstb.1995.0029
| url=http://journals.royalsociety.org/content/32l541667hj3071k/ | accessdate=2008-07-31
| year=1995
}}</ref>
*The earliest [[halkieriid]]s were a "sister" group to the molluscs, in other words descendants of a fairly closely-related common ancestor.
*The halkieriids which Conway Morris had found in Greenland's [[Sirius Passet]] [[lagerstätte]] were a "sister" group to [[brachiopods]], animals whose modern forms have bivalve shells but differ from molluscs in having muscular stalks and a distinctive feeding apparatus, the [[lophophore]].
*Another halkieriid [[genus]], [[Thambetolepis]], was a "great aunt" of annelids and ''Wiwaxia'' was an "aunt" of annelids.<ref name="ConwayMorrisPeel1995" />

Marine biologist Amélie H. Scheltema ''et al'' (2003) argued that ''Wiwaxia''’s feeding apparatus is very similar to the [[radula]]s of some modern shell-less [[aplacophora| aplacophoran]] [[mollusc]]s, and that the sclerites of the two groups are very similar. They concluded that ''Wiwaxia'' was a member of a [[clade]] that includes molluscs.<ref>{{ cite journal
| title=Original Molluscan Radula: Comparisons Among Aplacophora, Polyplacophora, Gastropoda, and the Cambrian Fossil ''Wiwaxia corrugata''
| author=Scheltema, A.H., Kerth, K., and Kuzirian, A.M.
| journal=Journal of Morphology | volume=257 |pages=219–245 | date=2003 | doi= 10.1002/jmor.10121
| url=http://www3.interscience.wiley.com/journal/104528759/abstract?CRETRY=1&SRETRY=0
| accessdate=2008-08-05
}}</ref>

Danish zoologist Danny Eibye-Jacobsen argued in 2004 that ''Wiwaxia'' lacks any characters that would firmly place it as a [[polychaete]] or [[annelid]]. Eibye-Jacobsen regarded bristles as a feature shared by molluscs, annelids and brachiopods. Hence even if ''Wiwaxia''’s sclerites closely resembled bristles, which he doubted, this would not prove that ''Wiwaxia''’s closest relative were annelids. He also pointed out that the very different numbers of sclerites in the various zones of ''Wiwaxia''’s body do not correspond to any reasonable pattern of segmentation; while Eibye-Jacobsen did not think that this alone would prevent classification of ''Wiwaxia'' as a polychaete, he thought it was a serious objection given the lack of other clearly polychaete features. In his opinion there were no strong grounds for classifying ''Wiwaxia'' as a proto-annelid or a proto-mollusc, although he thought the ojections against classification as a proto-annelid were the stronger.<ref name="EibyeJacobsen2004">{{cite journal
| title=A reevaluation of Wiwaxia and the polychaetes of the Burgess Shale
| author=Eibye-Jacobsen, D. | journal=Lethaia | volume=37 | issue=3 | pages=317–335
| month=September | year=2004 |doi=10.1080/00241160410002027
| url=http://www.ingentaconnect.com/content/tandf/slet/2004/00000037/00000003/art00011;jsessionid=383hjtjp6370h.alexandra
| accessdate = 2008-08-04
}}</ref>

Butterfield returned to the debate in 2006, repeating the arguments he presented in 1990 for regarding ''Wiwaxia'' as an early polychaete and adding that, while bristles are a feature of several groups, they appear as a covering over the back only in polychaetes.<ref name=Butterfield2006>{{cite journal
| author = Butterfield, N.J. | year = 2006
| title = Hooking some stem-group ‘‘worms’’: fossil lophotrochozoans in the Burgess Shale
| journal = Bioessays | volume = 28 | issue = 12 | pages = 1161-6 | doi = 10.1002/bies.20507
| url=http://www3.interscience.wiley.com/journal/113471993/abstract?CRETRY=1&SRETRY=0
| accessdate=2008-08-06
}}</ref>
[[Image:Wiwaxia_Smithsonian.JPG|left|thumb|Fossil specimen on display at the [[National Museum of Natural History|Smithsonian]] in Washington, DC]]
==See also==
* [[Coeloscleritophoran]]

==References==
{{reflist}}

==External links==
*[[Pharyngula (blog)|Pharyngula]] [http://scienceblogs.com/pharyngula/2007/03/orthozanclus.php entry] on ''[[Orthrozanclus reburrus]]''

{{portal|Paleontology}}

[[Category:Burgess Shale fossils]]
[[Category:Cambrian animals]]
[[Category:Prehistoric animals]]

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