| Abstract: | Although the soil surface may look like dirt to you, it is full of living organisms that are a vital part of desert ecosystems. This veneer of life is called a biological soil crust. These crusts are found throughout the world, from hot deserts to polar regions. Crusts generally cover all soil spaces not occupied by green plants. In many areas, they comprise over 70% of the living ground cover and are key in reducing erosion, increasing water retention, and increasing soil fertility. In most dry regions, these crusts are dominated by cyanobacteria (previously called blue-green algae), which are one of the oldest known life forms. Communities of soil crusts also include lichens, mosses, microfungi, bacteria, and green algae.
These living organisms and their by-products create a continuous crust on the soil surface. The general color, surface appearance, and amount of coverage of these crusts vary depending on climate and disturbance patterns.
Immature crusts are generally flat and the color of the soil, which makes them difficult to distinguish from bare ground. Mature crusts, in contrast, are usually bumpy and dark-colored due to the presence of lichens, mosses, and high densities of cyanobacteria and other organisms. |
| Genre: | USGS Numbered Series |
| ProdID: | 50062 |
| Citation Author: | Belnap, Jayne |
| Citation Contributing Office: | USGS Forest and Rangeland Ecosystem Science Center |
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| Citation Language: | ENGLISH |
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| Citation No Pagination: | N |
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| Citation Phsyical Description: | 2 p. |
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| Citation Publisher: | Geological Survey (U.S.) |
| Citation Series: | Fact Sheet |
| Citation Series Code: | FS |
| Citation Series Number: | 065-01 |
| Citation Search Results Text: | Biological Soil Crusts: Webs of Life in the Desert; 2001; FS; 065-01; Belnap, Jayne |
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| Citation Year: | 2001 |
| Type: | citation/reference |
| Text: | Biological Soil Crusts: Webs of Life in the Desert; 2001; FS; 065-01; Belnap, Jayne |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/fs_065_01.jpg |
| URL (DOCUMENT): | http://pubs.usgs.gov/fs/2001/0065/pdf/fs065-01.pdf |
| URL (INDEX PAGE): | http://pubs.usgs.gov/fs/2001/0065/ |
| Date Other: | Sat, 1 Jan 1994 00:00 -0600 |
| Publisher: | Geological Survey (U.S.) |
