The temperature of almost all of the deep ocean is only a few degrees above freezing, 39F (4C)
In the clearest water at midday, sunlight dims by one-tenth about every 250 feet (75 m). Humans can just barely see light below 1600 feet (500 m), at about one-millionth of the intensity at the surface.
Most of the deep ocean is under pressures of 3000 to 9000 pounds per square inch (or about the equivalent of 100 to 300 times the air pressure in automobile tires).
Shrunken polystyrene cups make
great dive souvenirs. Divers decorate the cups and attach them to the outside
of the research sub. In deep waters, intense pressure forces the air pockets
out and shrinks the cups (passengers inside are protected by metal and thick
35,802 ft (10,912 m) At the deepest point of the trench (and the deepest point on earth) the pressure is over 8 tons per square inch, or the equivalent of an average-sized woman holding up 48 jumbo jets.
Ocean Planet Exhibition Floorplan
gene carl feldman (email@example.com) (301) 286-9428
Judith Gradwohl, Smithsonian Institution (Curator/Ocean Planet)