Publication Date:
2019-07-17
Description:
Recent applications of molecular genetics to edaphic microbial communities of the
McMurdo Dry Valleys and elsewhere have rejected a long-held belief that Antarctic soils
contain extremely limited microbial diversity. The Inter-Valley Soil Comparative Survey
(IVSCS) aims to elucidate the factors shaping these unique microbial communities and their
biogeography by integrating molecular genetic approaches with biogeochemical analyses.
Although the microbial communities of Dry Valley soils may be complex, there is little doubt
that the ecosystem’s food web is relatively simple, and evidence suggests that
physicochemical conditions may play the dominant role in shaping microbial communities.
To examine this hypothesis, bacterial communities from representative soil samples collected
in four geographically disparate Dry Valleys were analyzed using molecular genetic tools,
including pyrosequencing of 16S rRNA gene PCR amplicons. Results show that the four
communities are structurally and phylogenetically distinct, and possess significantly different
levels of diversity. Strikingly, only 2 of 214 phylotypes were found in all four valleys,
challenging a widespread assumption that the microbiota of the Dry Valleys is composed of a
few cosmopolitan species. Analysis of soil geochemical properties indicated that salt content,
alongside altitude and [Cu2+], was significantly correlated with differences in microbial
communities. Our results indicate that the microbial ecology of Dry Valley soils is highly
localized and that physicochemical factors potentially play major roles in shaping the
microbiology of ice-free areas of Antarctica. These findings hint at links between Dry Valley
glacial geomorphology and microbial ecology, and raise previously unrecognized issues
related to environmental management of this unique ecosystem.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
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