The abyssal zone contains the very deep benthic communities near the bottom of oceans. This zone remains in perpetual darkness, at depths varying from 2,000 to 6,000 meters (6,560 to 19,680 feet). Its permanent inhabitants – for example, the Swallower fish, Tripod fish, Deep-sea angler, and the Deep-sea squid – are able to withstand the immense pressures of the ocean depths, up to 775 kilograms per square centimeter (76 megapascals or 4.92 long tons force per square inch). The deep trenches or fissures that plunge down thousands of feet below the ocean floor – for example, the midoceanic trenches such as the Marianas in the Pacific – are almost unexplored. Only the French bathyscaph Trieste has been able to descend to these depths. These regions are also characterized by continuous cold and lack of nutrients. The worlds oceans as seen from the South Pacific Ocean (from Okeanos, Greek for river, the ancient Greeks noticed that a strong current flowed off Gibraltar, and assumed it was a great river); covers almost three quarters (71%) of the surface of the Earth, and nearly half of the... Binomial name Bathypterois grallator (Goode & Bean, 1886) The tripod fish (Bathypterois grallator) is an unusual bathypelagic (deep sea) fish. ... The deprecated unit kilogram-force (kgf) or kilopond (kp) is the force exerted by one kilogram of mass in standard Earth gravity (defined as exactly 9. ... The megapascal, symbol MPa is an SI unit of pressure. ... A long ton is the name used in the US for the unit called the ton in the avoirdupois or Imperial system of measurements, as used (alongside the metric system) in the United Kingdom and to some extent in other Commonwealth countries. ... Mariana Islands (sometimes called The Marianas; up to the early 20th century sometimes called the Ladrone Islands) are a group of islands made up by the summits of 15 volcanic mountains in the Pacific Ocean. ... For other meanings of Pacific, see Pacific (disambiguation). ...