Cold Seep Essay

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Cold Seeps A cold seep (sometimes called a cold vent) is an area of the ocean floor where hydrogen sulfide, methane and other hydrocarbon-rich fluid seepage occurs. Cold seeps are distinct from hydrothermal vents: the former's emissions are of the same temperature as the surrounding seawater, whereas the latter's emissions are super-heated. Cold seeps constitute a biome supporting several endemic species. Cold seeps occur over fissures on the seafloor caused by tectonic activity. Oil and methane "seep" out of those fissures, are diffused by sediment, and emerge over an area several hundred meters wide. Methane (CH4) is the main component of what we commonly refer to as natural gas. In addition to being an important energy source for humans, methane also forms the basis of a cold seep ecosystem. Cold seep biota below 200 m typically exhibit much greater systematic specialization and reliance on chemoautotrophy than those from shelf depths. Deep-sea seeps sediments are highly heterogeneous. They sustain different geochemical and microbial processes that are reflected in a complex mosaic of habitats inhabited by a mixture of specialist (heterotrophic and symbiotic-associated) and background fauna. During the initial stage, when methane is relatively abundant, dense mussel beds also form near the cold seep. Mostly composed of species in the genus Bathymodiolus, these mussels do not directly consume food. Instead, they are nourished by symbiotic bacteria that also produce energy from methane, similar to their relatives that form mats. Chemosynthetic bivalves are prominent constituents of the fauna of cold seeps and are represented in that setting by five families: Solemyidae, Lucinidae, Vesicomyidae, Thyasiridae and Mytilidae. This microbial activity produces calcium carbonate (CaCO3), which is deposited on the seafloor and forms a layer of rock. During a
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