The deep cold biosphere: facts and hypothesis

摘要: Deep subterranean layers may be regarded as the most stable environment for microorganisms where possible fluctuations should explained by geological events only. The analysis of total amount has revealed that in sedimentary deposits their number is only one order magnitude lower than same parameter soil. Taking into account depth sediments microbial biomass rocks to considerably larger soils. Permafrost constant and among deep habitats. Microbial communities survive permafrost at least some millions years. diversity organisms activities after thawing displays distinct differences those abundance bacterial assumed comparable frozen unfrozen sediments. Therefore, permanently low temperature a stabilizing factor sustains life cold biotopes. Studies different lithology age suggest level subzero duration its influence define ratio between hypometabolic cells, readily reversible proliferation, so-called viable but non-culturable cells (deep resting cells). To certain extent, cell aggregates extracellular matrix an additional survival mechanism supporting state cells. There indirect evidence adaptive physiological biochemical processes during long-term impact cold.