alteration of consciousness during deep sea diving is known as
Nitrogen narcosis Narcosis while diving (also known as nitrogen narcosis, inert gas narcosis, raptures of the deep, Martini effect) is a reversible alteration in consciousness that occurs while diving at depth. It is caused by the anesthetic effect of certain gases at high pressure. The Greek word ναρκωσις (narcosis) is derived from narke, "temporary decline or loss of senses and movement, numbness", a term used by Homer and Hippocrates.[1] Narcosis produces a state similar to drunkenness (alcohol intoxication), or nitrous oxide inhalation. It can occur during shallow dives, but does not usually become noticeable at depths less than 30 meters (100 ft).
Challenger Deep On 26 March 2012 (local time), Canadian film director James Cameron made a solo manned descent in the DSV Deepsea Challenger to the bottom of the Challenger Deep.[9][10][11][26] At approximately 05:15 ChST on 26 March (19:15 UTC on 25 March), the descent began.[27] At 07:52 ChST (21:52 UTC), Deepsea Challenger arrived at the bottom. The descent lasted 2 hours and 36 minutes and the recorded depth was 10,898.4 metres (35,756 ft) when Deepsea Challenger touched down.[28] Cameron had planned to spend about six hours near the ocean floor exploring but decided to start the ascent to the surface after only 2 hours and 34 minutes.[29] The time on the bottom was shortened because a hydraulic fluid leak in the lines controlling the manipulator arm obscured the visibility out the only viewing port. It also caused the loss of the submersible's starboard thrusters.[30] At around 12:00 ChST (02:00 UTC on 26 March), the Deepsea Challenger website says the sub resurfaced after a 90-minute ascent,[31] although Paul Allen's tweets indicate the ascent took only about 67 minutes.[32] During a post-dive press conference Cameron said: "I landed on a very soft, almost gelatinous flat plain. Once I got my bearings, I drove across it for quite a distance ... and finally worked my way up the slope." The whole time, Cameron said, he didn't see any fish, or any living creatures more than an inch (2.5 cm) long: "The only free swimmers I saw were small amphipods"—shrimplike bottom-feeders.[33]