Nitrogen economy of endolithic microbial communities in hot and cold deserts

摘要: The source of combined nitrogen in endolithic microbial communities was studied samples from desert localities North and South America, the Middle East, Africa, Antarctica. Nitrogen fixation (acetylene reduction) seems to occur only exceptionally. Evidence suggests that, general, for microorganisms deserts is abiotically fixed produced by atmospheric electric discharges (lightning or aurorae), conveyed rock precipitation. apparently not a limiting factor these low-productivity communities. An incomplete cycle be present which includes following pathways: supply nitrates ammonia atmosphere; decomposition organic matter ammonia; reassimilation volatilization; loss through weathering (only certain Antarctic rocks); biological (exceptional).