Subsurface biosphere

Fossil remains of a deep subsurface biosphere are unequivocal traces of former deep life, as contamination via drilling or mining procedures can be excluded. However, traces of fossilized eukaryotic life in deep subterranean environments are extremely rare (Schumann et al., 2004). There are fossil representatives of all known domains of life, and while fossilized fungi do exist, they are exceptionally rare. The standard paleo-botanical literature refers to the lack of fossil records of fungi (Pia, 1927 Gothan Weyland, 1964 Pirozynski, 1976). 

Evidence for a subsurface biosphere at deep-sea hydrothermal vents Deming and Baross (1993) proposed the study of accessible black smokers and the ejecta of seafloor diking eruptive events (see below) as indirect windows to the subsurface. Since then, numerous studies have documented a variety of evidence supporting the existence of a subsurface biosphere below mid-ocean ridges, although the quantitative importance of this biosphere remains to be established (Kelley etal., 2002). 

The origin of microbes present in hydrothermal plumes is believed to be either from a subsurface biosphere maintained by the rapid mixing processes that take place during plume formation or from entrained seawater microbes (Winn etal., 1995 Cowen etal., 1998,1999). In the latter case, most of the organisms would not be able to grow, but a small segment of the population may thrive and multiply as plumes move away from the ridge crest. Similar forms to plume bacteria are common on rock surfaces near vents and on sulphide structures (Jannasch ... 

Avery, E.R., Zierenberg, R.A. and Nelson, D.C. (2000) Seafloor oxidation of massive sulfide deposits, Ridge Theoretical Institute - The Subsurface Biosphere at Mid-Ocean Ridges, July 27-August 1, Big Sky, Montana, p. 6. 

Deming, J.W. and Baross, J.A. (1993) Deep-sea smokers - windows to a subsurface biosphere. Geo-chimica et Cosmochimica Acta, 57, 3219—3230. 

Reysenbach, A.-L., Holm, N.G., Hershberger, H.D., Prieur, D. and Jeanthon, C. (1998) In search of a subsurface biosphere at a slow-spreading ridge. Proceedings of the Ocean Drilling Program, Scientific Results, 158, 355-360. 

Lin, L.-H., Slater, G.F., Lollar, B.S., Lacrampe-Couloume, G, Onstott, T.C. (2005). The yield and isotopic composition of radiolytic Hj, a potential energy source for the deep subsurface biosphere. Geochimica et Cosmochimica Acta, 69, 893-903. 

Some injected wastes are persistent health hazards that need to be isolated from the biosphere indefinitely. For this reason, and because of the environmental and operational problems posed by loss of permeability or formation caving, well operators seek to avoid deterioration of the formation accepting the wastes and its confining layers. When wastes are injected, they are commonly far from chemical equilibrium with the minerals in the formation and, therefore, can be expected to react extensively with them (Boulding, 1990). The potential for subsurface damage by chemical reaction, nonetheless, has seldom been considered in the design of injection wells. 

Rouxel O, Eouquet Y, Ludden JN (2004) Subsurface processes at the Lucky Strike hydrothermal field, Mid-Atlantic Ridge evidence from sulfur, selenium and iron isotopes. Geochim Cosmochim Acta, in press Schauble EA, Rossman GR, Taylor HP (2001) Theoretical estimates of equilibrium Ee-isotope fractionations from vibrational spectroscopy. Geochim Cosmochim Acta 65 2487-2497 Schopf JW (1992) Paleobiology of the Archaen. Im The Proterozoic Biosphere A Multidisciplinary Study. Schopf JW, Klein C (eds) p 25-39... 

The available literature clearly shows that fungi are present in even the deepest sediments of the sea, and therefore could potentially be buried with sediments. Little is known about marine filamentous fungi and yeasts, and almost nothing about their life-cycles or metabolism under deep-sea and sub-sea-floor conditions. If they survive burial, they will eventually become part of the sub-sea-floor biosphere. No direct data describe how long fungi can survive in subsurface environments. Data from dried soil specimens indicate that fungi survive fewer than 50-100 years separated from their autochthonous surface environment (Sneath, 1962). However, sub-sea-floor conditions may very well be more favourable for preservation than are soil conditions. 

The potential that life can exist in a subsurface realm, independent of photosynthetic productivity, has raised the possibility that habitable niches may exist elsewhere in our solar system [84]. As defined by the long-term stability of liquid water, the Earth is at present the only body in the solar system capable of supporting a surface biosphere. Any biosphere elsewhere in the solar system would therefore be confined to the deep subsurface. Specifically, attention has been focused on Mars and Europa, both of which may support... 

At the closure of the facility, boreholes, shafts and access tunnels are sealed to restore the geosphere properties as well as possible.The geosphere is in contact with the biosphere, made up of surface and subsurface areas and resources easily accessible to human activities. 

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