Properties and spatial distribution of microbiotic crusts in the Negev Desert, Israel

Playing a cardinal role in surface stabilization and in carbon and nitrogen fixation, microbiotic crusts play a crucial role in arid regions where they may serve as useful biomarkers for wind power and wetness duration. This is especially the case on relatively unstable and infertile sand dunes in the Negev Desert where high correlations between the crust chlorophyll content and the daytime wetness duration were found. Yet, only scarce data are available as to the possible link between the chlorophyll content and other physical (color, thickness, strength, crack density, surface roughness and infiltrability) and biological (protein, carbohydrate, organic matter and species composition) factors, which determine, in turn, the crust type and its effect upon geomorphological and ecological processes. No data are available on crust type distribution. These were the aims of the current research.