| Abstract from DBPedia | The deep sea is broadly defined as the ocean depth where light begins to fade, at an approximate depth of 200 metres (656 feet) or the point of transition from continental shelves to continental slopes. Conditions within the deep sea are a combination of low temperatures, darkness and high pressure The deep sea is considered the least explored Earth biome, with the extreme conditions making the environment difficult to access and explore. Organisms living within the deep sea have a variety of adaptations to survive in these conditions. Organisms can survive in the deep sea through a number of feeding methods including scavenging, predation and filtration, with a number of organisms surviving by feeding on marine snow. Marine snow is organic material that has fallen from upper waters into the deep sea. In 1960, the bathyscaphe Trieste descended to the bottom of the Mariana Trench near Guam, at 10,911 m (35,797 ft; 6.780 mi), the deepest known spot in any ocean. If Mount Everest (8,848 m or 29,029 ft or 5.498 mi) were submerged there, its peak would be more than 2 km (1.2 mi) beneath the surface. After the Trieste was retired, the Japanese remote-operated vehicle (ROV) Kaikō was the only vessel capable of reaching this depth until it was lost at sea in 2003. In May and June 2009, the hybrid-ROV Nereus returned to the Challenger Deep for a series of three dives to depths exceeding 10,900 m (35,800 ft; 6.8 mi).深海（しんかい）とは、明確な定義はないが、一般的には200m以深の海域帯を指す。 深海には光合成に必要な太陽光が届かないため、表層とは環境や生態系が大きく異なる。高水圧・低水温・暗黒などの過酷な環境条件に適応するため、生物は独自の進化を遂げており、表層の生物からは想像できないほど特異な形態・生態を持つものも存在する。また、水温や密度の相異のため、表層と深海の海水は混合せず、ほぼ独立した海水循環システムが存在する。 地球の海の平均水深は 3,729メートルであり、深海は海面面積の約80%を占める。21世紀の現在でも大水圧に阻まれて深海探査は容易でなく、大深度潜水が可能な有人や無人の潜水艇や探査船を保有する国は数少ないなどから、深海のほとんどは未踏の領域である。 (Source: http://dbpedia.org/resource/Deep_sea) |
