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 puroposes[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 rage 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.