Microbial Ecology of Desert Soils

Fate and transport processes controlling the migration of hazardous and radioactive materials from the Area 5 Radioactive Waste Management Site (RWMS)

“…Under very dry soil conditions, however, microbial activity is inhibited, and the relative contribution of biotic processes to the dissipation of organic pollutants is not likely. No significant microbial proliferation may be expected at water potentials < -40 MPa (Skujins, 1984).…”

“…Soil microorganisms in arid environments are subjected to the same external physical factors as in other soils, except that the organisms are subjected to prolonged harsh environmental extremes (Skujins, 1984). Relatively little detailed information about arid-soil biological processes is available in comparison with the body of knowledge about physical and biological processes of marginally utilizable arid areas or semiarid cultivated soils ( Skujins, 1984;Focht and Martin, 1979;Andraski, 1992).…”

“…Relatively little detailed information about arid-soil biological processes is available in comparison with the body of knowledge about physical and biological processes of marginally utilizable arid areas or semiarid cultivated soils ( Skujins, 1984;Focht and Martin, 1979;Andraski, 1992).…”

“…Extremely dry conditions (drought) produce a set of stresses for which the microorganisms must either adapt to desiccation, prevent desiccation, or die (Singer and Munns, 1987). Microorganisms living in dry desert soils must be able to tolerate long periods of desiccation (Skujins, 1984). Many bacteria can prevent desiccation and adapt to low water potentials and high salinity by maintaining a high internal concentration of solutes.…”

“…When water becomes available, the spores germinate and the microorganisms can actively grow and reproduce (Atlas and Bartha, 1987). Nonetheless, most microorganisms in desert soils are neither spore formers nor develop any restricting structures (Skujins, 1984). Elwan and Diab (1970) showed that in very dry sands (0.95-2.5 percent water) which were also poor in organic matter (.09-.033 percent organic C), at least 84 percent of the bacteria was in a vegetative state.…”