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The Blooming Desert: Bacteria and Wildflowers Paula R. Gossard July 27, 2005 Creating a Wildflower Collection Desert Wildflowers have… • • • • Fewer leaves than mountain wildflowers, with any compact foliage closer to the ground Smaller leaves on long, wooly or waxy stems Smaller flowers, with fewer blooms per plant Less variety: 30 specimens in 5 days at four locations vs. 20 specimens in 4 hours at one location Winogradsky Columns A miniature ecosystem that illustrates microbial succession Different organisms grow at different locations in the column, depending on their needs Watering Hole Sediment Cave Extremophiles Sulfur bacteria get their energy from hydrogen sulfide “Snottites” are cave formations composed of bacteria, bacterial “slime” and bits of minerals Biological Soil Crusts Formed by living organisms and their by-products Surface soil particles are bound together by organic materials Biological Soil Crusts Immature crusts are generally flat and the color of the soil; they look like bare ground Mature crusts are usually bumpy and dark-colored due to the presence of many organisms Cyanobacteria, green and brown algae, mosses, lichens, and sometimes liverwort or fungi live in crusts Ecological Roles of Crusts Aid in rainfall absorption Protect soil from erosion and stabilize slopes Contribute nutrients and organic matter to desert soils Cyanobacterial mucilage Cyanobacterial mucilage Human Impact on Crusts Compressional stresses cause great damage to crusts Windborne air pollutants damage crusts Recovery can take from 20-250 years
