Van Dover is a researcher with the University of Alaska Fairbanks' Institute of Marine Science. Much of the nocturnal topography of the sea floor has been shaped by molten rock forced upward in areas where plates in Earth's crust spread apart, Van Dover said. Heaps of lava quickly cooled by sea water have formed incredible, yet unseen, mountain ranges. Scattered amidst these mountains are tubes that spew the exhaust of the reaction between near-freezing sea water and lava. These chimneys, known as hydrothermal vents, exhale a mixture of sea water and minerals at a temperature of about 660 degrees Fahrenheit.
Black smokers exist in an even blacker world.
Since sea water absorbs sunlight, the ocean darkens with depth, Van Dover said. Below a few hundred feet, the only flashes of light come from fish and other tiny creatures that occasionally glow to attract mates or find prey. Scientists explore this inky darkness using submarines and shipboard-operated diving vehicles equipped with cameras and spotlights. By illuminating the sea floor, researchers have found a quirky group of animals that live close to the vents. Near a vent deep under the Atlantic Ocean, researchers in 1985 found a species of shrimp that lacked the eyestalks and corneas of the shrimp we eat.