Topic 16 -
Cryptobiotic Soils: Keystone of the Colorado Plateau
Goals:
what are cryptobiotic crusts?
where are they found?
what roles do they play in cold desert ecosystems (like the Colo. Plateau)?
why are they endangered? what human activities threaten soil crusts?
origin of soils on the Colo. Plateau
so what...? (larger scale impacts)
Questions & Answers:
Link for more information on biological soil crusts: http://www.soilcrust.org/
Images -
| Figure 4. Crust in sandy soils. The visible fibers are Microcoleus vaginatus. Note how Microcoleus connects the otherwise loose sand grains together, thus preventing wind and water erosion. Microcoleus is important in enhancing water and nutrient relations within the soil, as well. Scale bar is 100 micrometers. |
from: http://geochange.er.usgs.gov/sw/impacts/biology/crypto/
| Figure 3. Microcoleus filaments (lower left) emerging from mucilagenous sheath (upper right). Scale bar is 10 micrometers. |
Figure 1. Filaments of Microcoleus vaginatus (x 3000), the dominant organism in the crust. Individual cells abut each other to form the filaments.
Open spaces covered by biological soil crusts, a highly specialized community
of cyanobacteria, mosses, and lichens.