BIOL241 Final: Unit 4- Terrestrial and Aquatic Environments as Microbial Habitats
1 Apr 2016
School
Department
Course
Professor
Document Summary
Look at environments- near share have plants but in centre no plant life. Soils: may be organic (rarely) or (most commonly) inorganic (focus) Organic 20%+ organic matter formed by sedimentation action (rare) soil formation: a complex process; it requires many, many years (i. e. , 1000s) to reach mature soil profile. 1. microbial activities contribute (metabolic products, e. g. organic (activities produce) acids, co2), as do other physical and chemical processes (e. g. , freeze-thaw, wind and water erosion, dissolution by dilute acids) Form small particles and more animals (e. g. , worms) living in the soil also contribute to soil structure and fertility by mixing and aerating upper layers; plants by taking up water, releasing organics into the soil. Over centuries b/c 1 & 2 soil builds up. O-horizon: exposed organic matter on the soil surface i. e. fallings nettles to surface and decompose. A-horizon: high organic matter, topsoil closest to surface, + activity. Large microbial activity b/c organic matter from decomp"d o. high conc from root exodates.
