Taxonomic Composition and Photosynthetic Characteristics of the `Biological Soil Crusts' Covering Sand Dunes in the Western Negev Desert

We report laboratory studies that aim to characterize the microphyte community composition and metabolic features of crusts covering dunes in the Negev. The crusts are formed by at least one moss, four blue-green (Cyanobacteria) and two green (Chlorophyta) algal species with Microcoleus sociatus being dominant. The sheaths of the latter procaryotic alga, together with a contribution by moss rhizoides and protonemata, are responsible for stability of the topsoil crusts. Following moistening of the dry crust, CO 2 release took place, even in the light, until positive net photosynthesis was achieved (...)