Microbial secreted exopolysaccharides affect the hydrological behaviour of induced biological soil crusts in desert sandy soils

Extracellular polymeric matrix (EPS) of Biological Soil Crusts (BSCs) plays a key role in hydrological processes taking place at the topsoil in desert environments. Hydrophobicity, caused by the non-polar fractions of the exudates, and pore clogging, which is conversely caused by polar interactions, determines the final water content and distribution. The major ecological role played by EPS in improving fitness of the crustal microbial community against desiccation is widely accepted although in these complex ecosystems other concurring factors such as rainfall characteristics, soil texture and the biological composition of crusts create many difficulties in isolating the sole advantages given by the microbial exudates