History
Prior to the 19th century scientists assumed life was sparse in the deep ocean. In the 1870s Sir Charles Thompson and colleagues aboard the Challenger expedition discovered many deep-sea creatures of widely varying types.
The first discovery of any deep-sea chemosynthetic community including higher animals was unexpectedly made at hydrothermal vents in the eastern Pacific Ocean during geological explorations (Corliss et al., 1979). Two scientists, J. Corliss and J. van Andel, first witnessed dense chemosynthetic clam beds from the submersible DSV Alvin on February 17, 1977, after their unanticipated discovery using a remote camera sled two days before.
The Challenger Deep is the deepest surveyed point of all of Earth's oceans; it is located at the southern end of the Mariana Trench near the Mariana Islands group. The depression is named after HMS Challenger, whose researchers made the first recordings of its depth on 23 March 1875 at station 225. The reported depth was 4,475 fathoms (8184 meters) based on two separate soundings. In 1960, Don Walsh and Jacques Piccard descended to the bottom of the Challenger Deep in the Trieste bathyscaphe. At this great depth a small flounder-like fish was seen moving away from the spotlight of the bathyscaphe.
The Japanese remote operated vehicle (ROV) Kaiko became the second vessel to reach the bottom of the Challenger Deep in March 1995. Nereus, a hybrid remotely operated vehicle (HROV) of the Woods Hole Oceanographic Institution, is the only vehicle capable of exploring ocean depths beyond 7000 meters. Nereus reached a depth of 10,902 meters at the Challenger Deep on May 31, 2009. On 1 June 2009, sonar mapping of the Challenger Deep by the Simrad EM120 multibeam sonar bathymetry system aboard the R/V Kilo Moana indicated a maximum depth of 10971 meters (6.82 miles). The sonar system uses phase and amplitude bottom detection, with an accuracy of better than 0.2% of water depth (this is an error of about 22 meters at this depth).
Read more about this topic: Deep Sea Communities
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—José Ortega Y Gasset (1883–1955)