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https://doi.org/10.5194/bgd-9-12711-2012
© Author(s) 2012. This work is distributed under
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/bgd-9-12711-2012
© Author(s) 2012. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 18 Sep 2012

Research article | 18 Sep 2012

Review status
This discussion paper is a preprint. It has been under review for the journal Biogeosciences (BG). The revised manuscript was not accepted.

Microstructure and hydraulic properties of biological soil crusts on sand dunes: a comparison between arid and temperate climates

T. Fischer1, A. Yair2, and M. Veste3 T. Fischer et al.
  • 1Central Analytical Laboratory, Brandenburg University of Technology, Cottbus, Germany
  • 2Department of Physical Geography, Hebrew University Jerusalem, Israel
  • 3Centre for Energy Technology Brandenburg e.V., Cottbus, Germany

Abstract. We studied the relationships between crust microstructure, infiltration and water holding capacity under arid and temperate conditions (Factor A: Climate) on biological soil crusts (BSCs) sampled along a~catena on mobile sand dunes (Factor B: Catena). The arid study site was located near Nizzana, Israel (precipitation: 86 mm a−1, PET: ~2500 mm a−1) and the temperate site near Lieberose, Germany (precipitation: 569 mm a−1, PET: ~780 mm a−1). BSCs were sampled near the dune crest, at the centre of the dune slope and at the dune base at each site. Scanning electron microscopy (SEM) was used to characterize BSC morphology and microstructure. Infiltration was determined using microinfiltrometry under controlled moisture conditions in the lab. Water holding capacities were determined after water saturation of the dry BSCs. Wettability of the crusts was characterized using a "repellency index", which was calculated from water and ethanol sorptivities. Irrespective of the climate, an accumulation of fine particles in the BSCs was found, increasing along the catena from dune crest to dune base. Texture was finer and water holding capacities of the underlying substrate were higher at the arid site, whereas surface wettability was reduced at the temperate site. At both sites, BSCs caused extra water holding capacity compared to the substrate. Infiltration rates decreased along the catena and were generally lower at the dune slope and base of the arid site. A mechanism of crust stabilization is proposed where BSCs benefit from increased texture and biomass mediated water supply, and where the water supply to higher plants was limited due to alteration of physico-chemical surface properties under temperate conditions.

T. Fischer et al.
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Interactive discussion
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Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
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T. Fischer et al.
T. Fischer et al.
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