Deep-sea community

A deep-sea community is any community of organisms associated by a shared habitat in the deep sea. Deep sea communities remain largely unexplored, due to the technological and logistical challenges and expense involved in visiting this remote biome. Because of the unique challenges (particularly the high barometric pressure, extremes of temperature and absence of light), it was long believed that little life existed in this hostile environment. Since the 19th century however, research has demonstrated that significant biodiversity exists in the deep sea. The three main sources of energy and nutrients for deep sea communities are marine snow, whale falls, and chemosynthesis at hydrothermal vents and cold seeps. Prior to the 19th century scientists assumed life was sparse in the deep ocean. In the 1870s Sir Charles Wyville Thomson 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.