Antarctic microbial communities in mineral deposits on Livingston Island, South Shetland Islands


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Lars.Ganzert [ at ] awi.de

Abstract

Livingston Island, located at the tip of the Antarctic Peninsula, is characterised by an oceanic polar climate with temperatures above 0°C during the austral summer and a mean annual precipitation between 400 and 500 mm. Under these conditions a soil formation can be observed and lichens, mosses and some higher plants are able to grow in this environment. With cultivation-independent methods, it is possible to analyse complex microbial networks in the face of diversity, abundance, ecology and their reaction on climate change. Here, we investigated the bacterial community structure of different habitats located on Livingston Island by polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) to get a first insight in the diversity of bacteria existing under these conditions. The aim of these studies is to identify the main microbial players in nutrient turnover within periglacial ecosystems of Antarctica.One transect and four separate profiles were sampled near the Bulgarian station St. Kliment Ohridski (62°38`S/60°21`W). Two soil profiles were characterised by permafrost. The investigated mineral soils showed mostly gravely sand texture. Moisture content of the soils ranged from 2.6% up to 15.6% and was partly quite variable within the different profiles. The values of total carbon and nitrogen were extremely low with <0.10 to 0.46% and <0.10%, respectively, except for the upper layers of the profiles T1-1 and T1-4 that were covered by mosses. PLFA concentration decreased with increasing depth, which correlates well with the TC values. DGGE patterns from amplification of DNA showed large varieties in the vertical profiles and between the different sites. Most sequences recovered from Antarctic soil profiles belong to the Bacteriodetes and to the Acidobacteria phylum.DGGE pictures showed a high diversity in most of the samples. The main influence on heterotrophic microbial growth and activity in low-nutrient habitats is probably the availability of organic compounds. Water can also be a limiting factor, but microorganisms seem to be well adapted to these conditions as it can be derived from the DGGE pattern. It is conceivable that the ways of C and N cycling in cold Antarctic habitats are short and that cold-adapted microorganisms might play a major role for the ecosystem development. To compare arctic and antarctic microbial communities phylogenetic investigations will be done using clone libraries for both Bacteria and Archaea.



Item Type
Conference (Talk)
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IPY
Peer revision
Not peer-reviewed
Publication Status
Published
Event Details
23rd International Polar Meeting, March 18-24, 2008, Münster, Germany..
Eprint ID
18559
Cite as
Ganzert, L. , Lipski, A. and Wagner, D. (2008): Antarctic microbial communities in mineral deposits on Livingston Island, South Shetland Islands , 23rd International Polar Meeting, March 18-24, 2008, Münster, Germany. .


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