TY - JOUR

T1 - Pore characteristics in biological soil crusts are independent of extracellular polymeric substances

AU - Felde, Vincent J.M.N.L.

AU - Rossi, Federico

AU - Colesie, Claudia

AU - Uteau-Puschmann, Daniel

AU - Horn, Rainer

AU - Felix-Henningsen, Peter

AU - De Philippis, Roberto

AU - Peth, Stephan

N1 - Funding information: We would like to acknowledge the financial support of the German Research Foundation (grant Fe218/14-2 ). VJMNLF and FR are grateful for financial support for mutual visits from the COST Action ES1104 . Thanks are due to Elke Müller and Elke Schneidenwind for conducting the texture analysis and Bettina Weber for providing the samples from the Karoo Desert. We thank Simon Berkowicz for his support during the fieldwork in the Negev and Andreas Dein for sampling permission at MEH, as well as Matthew Bowker and one anonymous reviewer for their very constructive comments.

PY - 2016/12/1

Y1 - 2016/12/1

N2 - Biological soil crusts (biocrusts) are considered key players in hydrological cycles of many arid environments. The phototrophic organisms in these crusts excrete extracellular polymeric substances (EPSs), which bind soil particles together, thereby stabilizing the soil surface. In a previous work, the non-invasive extraction of EPSs in biocrusts resulted in a change of their hydrological behavior. As this was suspected to be the effect of a change in their pore structure, we employed high resolution X-ray micro-tomography to investigate structural changes of biocrusts after EPS-extraction. We studied biocrusts from four different study sites in Svalbard, Germany, Israel and South Africa. Two different fractions of EPSs (tightly bound and colloidal) were extracted, using the same extraction method with two different solvents. Our results suggest that the extraction of EPSs did not result in structural differences at a resolution of 7 μm. We therefore conclude that the previously observed change in hydrological behavior is likely to be the result of a change of the physico-chemical properties of the very surface of the crust, rather than of its inner structure.

AB - Biological soil crusts (biocrusts) are considered key players in hydrological cycles of many arid environments. The phototrophic organisms in these crusts excrete extracellular polymeric substances (EPSs), which bind soil particles together, thereby stabilizing the soil surface. In a previous work, the non-invasive extraction of EPSs in biocrusts resulted in a change of their hydrological behavior. As this was suspected to be the effect of a change in their pore structure, we employed high resolution X-ray micro-tomography to investigate structural changes of biocrusts after EPS-extraction. We studied biocrusts from four different study sites in Svalbard, Germany, Israel and South Africa. Two different fractions of EPSs (tightly bound and colloidal) were extracted, using the same extraction method with two different solvents. Our results suggest that the extraction of EPSs did not result in structural differences at a resolution of 7 μm. We therefore conclude that the previously observed change in hydrological behavior is likely to be the result of a change of the physico-chemical properties of the very surface of the crust, rather than of its inner structure.

KW - Biocrusts

KW - Computed tomography

KW - Ecological restoration

KW - Extracellular polymeric substances

KW - Hydrological cycles

KW - Soil structure

UR - http://www.scopus.com/inward/record.url?scp=84987623670&partnerID=8YFLogxK

U2 - 10.1016/j.soilbio.2016.08.029

DO - 10.1016/j.soilbio.2016.08.029

M3 - Article

AN - SCOPUS:84987623670

VL - 103

SP - 294

EP - 299

JO - Soil Biology and Biochemistry

JF - Soil Biology and Biochemistry

SN - 0038-0717

ER -