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Primary microbial succession in a glacier forefield.

Abstract:

As the majority of Swiss glaciers are currently receding through global warming, the glacier forefields have become an interesting study site for primary microbial succession by phototrophic and heterotrophic microorganisms. Here, we characterize the structure and composition of the colonizer communities in newly exposed rock substrates. This study is carried out within the framework of the CCESBigLink interdisciplinary project of the ETH domain and the study site is the forefield of the Damma Glacier located in central Switzerland. We hypothesize that microbial diversity is increasing with distance from the glacier terminus and that both phototrophs and mineral weathering active heterotrophic bacteria are abundant. Soil samples from different sampling sites ranging from the glacier terminus devoid of vegetation until 100 year old soils covered by a dense vegetation were taken. Microbial communities were studied with culture-independent molecular approaches such as genetic profiling and sequencing of clone libraries. A high microbial diversity could be already found in the vicinity of the glacier terminus. Microbial diversity as expressed by the Shannon-Weaver diversity index was increased with distance from the glacier terminus. Both phototrophs and heterotrophic bacteria were abundant and their compositions were changing with distance from the glacier. Thus, a microbial succession from young to old soils is clearly visible and will now be investigated in more detail. Especially the driving forces and the mechanisms of carbon and nutrient acquisition during microbial succession will be evaluated.

Authors:

Zumsteg, Anita and Brunner, Ivano and Furrer, Gerhard and Plötze, Michael and Frey, Beat

Index Terms:

ClayGroup; Damma; granite; weathering; glacier; bacteria; BigLink; Brunner, Ivano; Frey, Beat; Furrer, Gerhard; Plotze, Michael; Zumsteg, Anita

Further Information:

Date published: 2009