Microphytic Soil Crusts and Desert Ecosystems Essay -- Soil Soils Agri

Microphytic Soil Crusts and depart from EcosystemsCommunities of micro-organisms create crusts on soils throughout semi-arid and arid regions of the world. These microphytic (also c everyed cryptogamic) crusts are formed when all or some of a diverse array of photosynthetic cyanobacteria (blue-green algae), fungi, bacteria, lichens and mosses, bind together with inorganic particles in the first few millimeters of a soil. Microphytic crusts are dominant feature in resign soils they are estimated to acquaint approximately 70% of desert soil biomass world wide (Belnap 1993). Un-restricted humans activity (farming, livestock grazing, recreation) results in the denigration or destruction these declamatory crusts. Many claim that soils and soil mechanisms are at the base of opposite ecosystem functions (Vitousek, Walker, Syers in Gillis 1994). In order to better understand and manage desert ecosystems, it is important to begin to understand how cryptogamic crusts form, what role crus ts play in shaping desert soil properties, and further, how crust removal might put soil quality and ecosystem stability. Crust Formation It is generally thought that the governing body of microphytic crusts begins with the establishment of cyanobacteria or agal communities on the soil surface (Campbell et. al. 1989). at that place are many different types of algae and cyanobacteria which exist in the new crusts, however it is difficult to ascertain which types of organisms are responsible for which processes of primal crust formation. Johansen postulates that crusts begin to form when filamentous cyanobacteria (as opposed to diatomic and nonfilamentous cyanobacteria or other algae) colonize the surface of soils in a period of moist weather (1993). As cyanobacter... ...ation and Dehydration. Soil Biology and Biochemistry v. 241101-1105.Johansen, J.R. (1993). Cryptogamic Crusts of Semi-arid and Arid Lands of North America. Journal of hycology v. 29141-147. Loope, W. L., Gifford, G. F. (1972). Influence of a Soil Microfloral Crust on Select Properties of Soils Under Pinyon-Juniper in southeastern Utah. Journal of Soil and Water Conservation v. July-August164-165. Metting, B. (1991). Biological Surface Features of semiarid Lands and Deserts. In Semiarid Lands and Deserts Soil resourcefulness and Reclamation , Skujins, J.(edt.). marcel Dekker, Inc, New York. pp. 257-293.Skujins, J. Microbial Ecology of Desert Soils. 62-85.West, N. E. (1991). Nutrient Cycling in Soils of Semiarid and Arid Regions. In Semiarid Lands and Deserts Soil Resource and Reclamation , Skujins, J.(edt.)Marcel Dekker, Inc, New York. pp. 295-327