Hydrothermal Vents Essay, Research Paper

Hydrothermal Vents are considered by scientists to be very unique and complex communities of organisms. The reason for this is due to the fact that unlike most other organisms, Hydrothermal Vents are not powered by the sun s energy. Most organisms on the Earth+s surface depend on plants to produce nutrients from sunlight. This process is called photosynthesis. These communities are unique in that they depend on a different food-making process other than photosynthesis. Bacteria at the vents make sugar by a process called chemosynthesis. Rather than light they depend on the chemicals that are released into the water by the vents. Bacteria use chemical energy to produce organic food molecules. The Vent organisms are dependent on the bacteria just as animals at the surface depend on plants for food production.

Hydrothermal Vents form at mid-ocean ridges. This is where the planet’s crustal plates are slowly spreading apart and magma is coming up from below to form mountain ranges. As cracks form at these spreading centers, seawater seeps a mile or two down into the hot rock. Enriched with minerals leached from the rock, the water heats and rises to the ocean floor to form a vent (Stover).

Vents are usually clustered in fields. Individual vent openings typically range from less than a half-inch to more than six feet in diameter. Such fields are normally found at a depth of more than a mile. Most have been discovered along the crest of the Mid-Oceanic Ridge, a 46,000- mile-long chain of mountains that seem to stretch all around the earth. A few vents have also been found at seamounts. Seamounts are underwater volcanoes that are not located at the intersection of crustal plates (Stover).

Hydrothermal vents provide habitat for many creatures that are not found anywhere else in the ocean. More than 300 new species have been identified since the first discovery of Hydrothermal Vents. Most of these organisms are tube-like worms of varied shapes, colors and sizes. However mussels, shrimps, and other small crustaceans are also present at these Thermal Vent sites (Popular Science).

The water at these sites can reach temperatures as high as 400C. However, the intense heat is limited to a small area. Within less than an inch of the vent opening, the water temperature drops to 2 C. This water is also rich in chemicals that serve as the key to life in these Vents (Popular Science).

The most prevalent chemical dissolved in vent water is hydrogen sulfide, which smells like rotten eggs. This chemical is produced when seawater reacts with sulfate in the rocks below the ocean floor. Vent bacteria often referred to, as chemoautotrophs are bacteria that get energy by pulling hydrogen and electrons from sulfur compounds. They use hydrogen sulfide as their energy source instead of sunlight. The bacteria sustain large numbers of organisms in the vent community. The organisms depend virtually solely on the bacteria for their nutrition (InfoPlease Encyclopedia).

This is done through a process called chemosynthesis. Chemosynthesis organisms are sulfide-oxidizing bacteria. Hydrogen sulfide is given off by the vents on the sea floor. The bacteria take the sulfur in the hydrogen sulfide and oxidize it producing energy. H2 + S —> H2S + energy. This energy drives all life forms in the deep sea vents, producing sugars, fats, and amino acids in living forms very much as plants do, but based on sulfur. Like photosynthesis this process is highly complex, but it sustains a huge number of organisms in the sea (Stover).