Ocean Zones

As oceanographers extend their studies to the deepest parts of the oceans, they continually encounter surprises in the kinds of marine life found there. One of the most interesting of these surprises was the discovery of deep sea vents found near the Galapagos Islands in 1977. These vents are located in regions where molten rock lies just below the surface of the seafloor, producing underwater hot springs. Volcanic "chimneys" form when the escaping super-heated water deposits dissolved minerals and gases upon coming in contact with the cold ocean water. The vents are surrounded by intriguing communities of organisms never seen before the 1977 discovery.

The basis for these non-photosynthesis based communities are bacteria that obtain energy from the oxidation of hydrogen sulfide escaping from the vents—a process called chemosynthesis. These bacteria (primary producers) are then used as foods by tube worms, huge clams, and mussels, and other organisms (primary consumers) living around the vents. These communities live in total isolation from photosynthetic-based communities (all other biological communities are photosynthesis based), and may provide clues to the nature of early life on Earth. Later studies have shown that hydrothermal vent communities exist in other parts of the ocean depths as well.