Mineral and Bacterial Diversities of Desert Sand Grains from South-East Morocco

Abstract

Mineralogy and microbiology of sand from Merzouga (Morocco) were simultaneously characterized, with the purpose of contributing to a better understanding of the geomicrobiology of deserts. In spite of very low measured bacterial biomass, bacterial diversity on each of the five defined mineralogical classes, was found high. An original grain by grain cultivation method enabled to obtain bacterial isolates with an unusually high recovery rate. The results of this study show that the genus Arthrobacter is well adapted to this environment with a preference for grains other than the dominant mineral quartz, and that the genera Chelatococcus and Saccharotrix are strongly attached to the grains.

Keywords:

• arid environment
• bacterial diversity
• sand mineralogy

This work was supported by the GEOMEX program grant from the Centre National de la Recherche Scientifique (CNRS). We thank Thomas Perrier who performed the granulometry analysis, Daniel Borschneck who performed the XRD analysis, Pr Baslé and the whole team of the Angers laboratory for SEM analysis and Geoff Manby for comments on the manuscript. William C. Ghiorse and two anonymous reviewers are acknowledged for detailed and constructive critics about an early version of this work, which led to strong improvements of this paper.