Cold seeps

Orphan VL, CH Hpuse, K-U Hinrichs, KD McKeegan, EE DeLong (2002) Multiple archaeal groups mediate methane oxidation in anoxic cold seep sediments. Proc Natl Acad USA 99 7663-7668. 

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 ... 

Table 19.3 Known and Proposed Microbial Metabolic Pathways at Deep-Sea Hydrothermal Vents and Cold Seeps. 

Hydrothermal vents and cold seeps, in deep zones of the oceans, are rich in microorganisms, mollusks, and worms, but without other forms of life that characterize the coasts (in particular photosynthetic organisms and their symbionts) and seamounts. 

Seamounts are areas of endemism, richer than the hydrothermal vents and cold seeps. A recent study, which required extensive sampling in diflicult areas, represents a change in the approach to marine biodiversity, with a focus on the species (Richer de Forges 2000). Moreover, contrary to the past, this study was not limited to organisms of commercial interest. 

Cold seeps are also areas of high hydrostatic pressure, rich in molhisks, particularly mytilids, which thrive on hydrogen sulfide from bacterial decomposition of sunken wood or whale bones (Distel 2000). 

The cold seeps of methane migration along the geologic faults or permeable stratigraphic horizons provide concentrations in excess of... 

The cold seeps at Hydrate Ridge, cause this site to be labeled a sweet spot of high hydrate concentration, relative to others such as the Blake-Bahama Ridge (ODP Leg 164) example that may be more representative of hydrate deposits in the world. Trehu et al. (2004a) estimate 1.5-2 x 108 m3(STP) of methane for the summit deposit, on the basis of the drilling and seismic data, which also define the limits of the deposit. Trehu (Personal Communication, January 8, 2006) indicated that this amount is comparable to a small gas field, not economical unless facilities are already in place. 

I introduced myself and explained that I had urgent business forCircospetto. We were ordered to wait. One man went into the guard room, two more came out to keep an eye on Bruno. A fourth was sent off to report to someone. Time passed. Graveyard cold seeped into my bones fog spitefully saturated all my clothes. I wished someone would offer me a seat, preferably close to a fire. 

AS rr WAS, he took me by surprise. On the last day of January, my father and I set out for our walk early in the afternoon. Gill had lit a bonfire in the orchard, so the air was pungent with woodsmoke frost clung to ruts in the path, and cold seeped through the soles of my boots. I thought wistfully of the kitchen, where I had left Mrs. Gill tucked close to the hearth with her skirts pulled up and her calves exposed to the blaze. 

Herzig P. M. and Hannington M. D. (2000) Input from the deep hot vents and cold seeps. In Marine Geochemistry (eds. H. D. Schultz and M. Zabel). Springer, Heidelberg, pp. 397-416. 

Elvert M., Suess E., Greinert J., and Whiticar M. J. (2000) Archaea mediating anaerobic methane oxidation in deep-sea sediments at cold seeps of the eastern Aleutian subduction zone. Org. Geochem. 31, 1175-1187. 

Pancost R. D., Hopmans E. C., and Sinninghe Damste J. S. (2001) Archaeal lipids in Mediterranean cold seeps molecular proxies for anaerobic methane oxidation. Geochim. Cosmochim. Acta 65, 1611 — 1627. 

Peckmann J., Thiel V., Michaelis W., Clari P., GaiUard C., Martire L., and Reitner L. (1999) Cold seep deposits of Beauvoisin (Oxfordian southeastern France) and Marmorito (Miocene northern Italy) microbially induced authigenic carbonates. Int. J. Earth Sci. 88, 60-75. 

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... 

Cold seeps also host abundant and diverse microbial communities that have important impacts on geochemical fluxes to the oceans (see review by Aharon, 2000 Orphan etal., 2001). There has been even less isolation and culturing of seep microbes compared to that of hydrothermal vents. Instead, most microbial investigations have used molecular tools to identify those organisms present in seep sediments (e.g. Boetius etal., 2000 Orphan etal., 2001, 2002 Teske etal.,... 

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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