Bacterial community structure of glacier forefields on siliceous and calcareous bedrock

Authors: lazzaro, A.; abegg, C.; zeyer, J.

Source: European Journal of Soil Science, Volume 60, Number 6, December 2009 , pp. 860-870(11)

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Abstract:

Summary

Forefields of retreating glaciers represent unique opportunities to investigate the initial phases of soil formation and microbial interactions with mineral surfaces. An open question concerns the physical and chemical driving-factors affecting the establishment of microbial communities in these young ecosystems. In this study we compared the bacterial community structure of six glacier forefield soils belonging to two contrasting bedrock categories (calcareous and siliceous) through T-RFLP profiling of the 16S rRNA gene. The community profiles were correlated with an array of physical (soil texture, water holding capacity, hours of sunshine, temperature, rainfall and exposure) and chemical (TC, TN, DOC, extractable nutrients and pH) factors using canonical correspondence analysis (CCA). A first comparison of the T-RFLP profiles suggested that the degree of operational taxonomic unit (OTU) diversity of these soils was similar, and that community structure was dominated by ubiquitous taxa. CCA showed that both physical (e.g. hours of sunshine or rainfall) and chemical factors (e.g. SO²⁻₄ or PO³⁻₄) played an equal role in shaping the soil bacterial communities. OTUs unique to specific sites appeared to be strongly influenced by the climatic regime and by texture. Overall, the community structure of the six glacial forefields showed no clear dependence on the bedrock categories.

Document Type: Research article

DOI: http://dx.doi.org/10.1111/j.1365-2389.2009.01182.x

Affiliations: 1: Institute of Biogeochemistry and Pollutant Dynamics, Federal Institute of Technology (ETH), ETH-Zentrum CHN G50.1, Universitätstrasse 16, CH-8092 Zürich, Switzerland

Publication date: 2009-12-01