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Role of biological soil crust cover in bioweathering and protection of sandstones in a semi‐arid landscape (Torrollones de Gabarda, Huesca, Spain)
Author(s) -
SouzaEgipsy Virginia,
Wierzchos Jacek,
Sancho Carlos,
Belmonte Anchel,
Ascaso Carmen
Publication year - 2004
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.1118
Subject(s) - crust , arid , weathering , geology , lichen , earth science , biomineralization , soil crust , earth (classical element) , geochemistry , ecology , paleontology , biology , physics , mathematical physics
Sandstone structural landscapes in the semi‐arid Torrollones de Gabarda area (Province of Huesca, NE Spain) are often covered by a well developed biological soil crust of lichens, mosses and cyanobacteria and black coatings on vertical surfaces. By using scanning electron microscopy with backscattered detector imaging, the biological soil crust studied evidenced high activity in the sandstone–crust interface. Processes such as physical disintegration, etching and dwelling as well as biomineralization by calcium oxalate and xation of mineral particles by extracellular polymeric substances were observed. On the horizontal sandstone surfaces these processes may cause the occurrence of gnammas and the development of a protective coating that favours intense aking when the crust is disturbed. On the sandstone cliffs, columnar and tafoni weathering development is clearly guided by the protective action of the biological soil crust. These qualitative observations are important to develop methodologies to address their quantitative importance in geomorphological processes in semi‐arid landscapes. Copyright © 2004 John Wiley & Sons, Ltd.