Fluid venting cold seeps

The hydrothermal-vent and cold-seep communities are dramatically different from the ecosystems typical of the abyssal plains. First, they are sites of high productivity supported by the abundant reduced chemicals in the hydrothermal fluids. Thus, these communities are independent of the skimpy flux of POM created in the surface waters that survives to settle on the seafloor. On the other hand, these communities have had to adapt to survival in hydrothermal systems that are ephemeral, disjunct, and characterized by extreme conditions, such as high temperatimes, high concentrations of reduced metals and sulfur, and low pH. As a result, vent communities have high rates of endemism. Of the 712 recorded vent species, 71% are found in no other setting ... 

One of the most spectacular features of deep-sea hydrothermal vents and cold seeps is the abundance and novelty of life they support. Vent and seep ecosystems share several fundamental similarities, despite the fact that they are quite different environments that originate from very different geotectonic settings. Hydrothermal vents are characterised by low to high temperature fluids (up to 400°C), with diffuse or highly focused fluid flow, while seeps are characterised by cold temperature fluids, generally with diffuse, slow fluid flow. Their most... 

Only deep-sea hydrothermal vents and cold-seeps are discussed in this chapter. Shallow vents and seeps are known from a variety of locations, from the littoral zone to several tens of metres (e.g. Holm, 1987 Jensen etal., 1992 Dando etal., 1994a,b, 1995). Shallow vents have many differences from their deeper counterparts. They lack metal-rich and extreme high temperature fluids, as well as large-scale mineral deposits. They also lack typical hydrothermal vent animals. Biomass production in both systems is lower than at deep-sea vents and deep... 

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