PERISCOP
The PERISCOP is a pressurized recovery device designed for retrieving deep-sea marine life at depths exceeding 2000 m.[1]: 881 The device was designed by Bruce Shillito and Gerard Hamel at the Universite Pierre et Marie Curie.[2]
Technology
The Periscop differs from previous pressurized recovery devices in that it contains separate chambers–one for capture, one for recovery under exterior pressure, and one for transfer to the lab while maintaining pressure. Previous recovery devices used one chamber for all purposes.[1]: 882 Attached to the device is an arm designed to capture samples by force of suction.[2] During ascent, pressure is maintained within the chamber by use of pressurized water. Pressurized gas was used in previous recovery devices, but it is not as safe as water.[1]: 883 Temperatures below 2000m usually range from 2-4 °C, and the device does not have a cooling system built in. Thus, samples may experience heat shock until they are returned to their usual temperature by surface equipment.[2] Upon surfacing, samples can be observed, filmed, and/or photographed through transparent view ports in the device.[1]: 884 Due to fluctuations in atmospheric pressure and temperature, the pressure in the device is not maintained perfectly. Recorded pressures during ascent and at the surface ranged from 74%-111% of the natural pressure.[1]: 884
Experiments
The device set a new record for the deepest live fish capture under pressure by capturing a live Pachycara at 2,300 m.[1]: 887 The previous record was 1,400 m.[2] The capture was also the first-ever performed at a hydrothermal vent.[2] The fish was reported to be alive and very active when observed on the surface.[1]: 886 The device has also recovered several shrimp species (Mirocaris fortunata, Chorocaris chacei, and Rimicaris exoculata) at vent fields Lucky Strike and Rainbow.[2] Subsequent unpressurized captures of the same species resulted in stupefaction followed by death, proving the necessity for such a device.[2] The experiments were performed from the ship Pourquoi Pas? during an IFREMER expedition.[2] Future experiments are planned to study the Pompeii worm, one of the most heat-tolerant animals on Earth.[2]
References
- ^ a b c d e f g SHILLITO, B (1 July 2008). "Live capture of megafauna from 2300m depth, using a newly designed Pressurized Recovery Device" (PDF). Deep Sea Research Part I: Oceanographic Research Papers. 55 (7): 881–889. doi:10.1016/j.dsr.2008.03.010. Retrieved 18 February 2011.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help); Unknown parameter|month=ignored (help)CS1 maint: date and year (link) - ^ a b c d e f g h i Lever, Anna-Marie (31 July 2008). "Live fish caught at record depth". BBC News. Retrieved 18 February 2011.