The variation of morphological features and mineralogical components of biological soil crusts in the Gurbantunggut Desert of Northwestern China |
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Authors: | Rongyi Chen Yuanming Zhang Yuan Li Wenshou Wei Jing Zhang Nan Wu |
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Institution: | (1) Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 830011 ürümqi, China;(2) Graduate School, Chinese Academy of Sciences, 100039 Beijing, China;(3) Urumchi Institute of Desert Meteorology, China Meteorological Administration, 830002 ürümqi, China;(4) Beijing Forest University, 100083 Beijing, China |
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Abstract: | Increasingly complex life forms were found in older biological soil crusts in the Gurbantaunggut Desert in Northwestern China.
These crusts may play a critical role in mineral erosion and desert soil formation by modifying the weathering environment
and ultimately affecting mineralogical variance. To test this hypothesis, variations in the morphological features and mineralogical
components of successional biological soil crusts at 1 cm were studied by optical microscopy, SEM and grain size analysis.
Concentrations of erosion-resistant minerals decreased with crust succession, while minerals susceptible to weathering increased
with crust development. Neogenetic minerals were found in late stage crusts, but not in early stage crusts. Silt and clay
concentrations were highest in early formation crusts and soil mean particle size decreased with crust succession. Cyanobacteria,
lichen and moss were shown to erode and etch rocks, and secondary minerals produced by weathering were localized with the
living organisms. Thus, more developed crusts appeared to contribute to greater mineral weathering and may be a major cause
of mineralogical variance seen in the Gurbantunggut Desert. The greater activity and complexity of older crusts, as well as
their improved moisture condition may function to accelerate mineral weathering. Therefore, protection and recovery of biological
crusts is vital for desert soil formation. |
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Keywords: | Gurbantunggut Desert Biological soil crust Morphology Mineral erosion |
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