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Download Lecture 14 soil and air microbiology - Cal State LA
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Acid Mine Drainage Microorganisms and Metal Toxicity • microorganisms can modify toxicity of metals • differing sensitivities of multicellular organisms and microorganisms to metals are basis of many antiseptic procedures Soil as an Environment for Microorganisms • dominated by inorganic geological material, which is modified by organisms to form soils • typically not water saturated, so O2 readily available • can contain “mini” aquatic environments Microorganisms in the Soil Environment peds – aggregated soil particles Microbial populations in soils • numbers can be very high – only small portion have been cultured • microbes are constantly being added to soil – most do not survive • make important contributions to biogeochemical cycling • gram-positive bacteria are important members of soil communities Deserts Soils • desert crusts – microbial communities on soil surface • cyanobacteria and associated commensals – help retain water from infrequent rainfalls – are fragile and easily damaged Desert crusts or cryptogamic crusts Biological soil crusts are formed by living organisms and their by-products, creating a crust of soil particles bound together by organic materials Crusts are predominantly composed of cyanobacteria, algae, mosses, and lichens. Liverworts, fungi, and bacteria can also be important components
