Evidence for successional development in Antarctic hypolithi

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TitleEvidence for successional development in Antarctic hypolithic bacterial communitiesAbstractHypoliths (cryptic microbial assemblages that develop on the undersides of translucent rocks) are significant contributors to regional C and N budgets in both hot and cold deserts. Previous studies in the Dry Valleys of Eastern Antarctica have reported three morphologically distinct hypolithic community types: cyanobacteria dominated (type I), fungus dominated (type II) and moss dominated (type III). Here we present terminal-restriction fragment length polymorphism analyses to elucidate the bacterial community structure in hypolithons and the surrounding soils. We show clear and robust distinction in bacterial composition between bulk surface soils and hypolithons. Moreover, the bacterial assemblages were similar in types II and III hypolithons and clearly distinct from those found in type I. Through 16S rRNA gene 454 pyrosequencing, we show that Proteobacteria dominated all three types of hypolithic communities. As expected, Cyanobacteria were more abundant in type I hypolithons, whereas Actinobacteria were relatively more abundant in types II and III hypolithons, and were the dominant group in soils. Using a probabilistic dissimilarity metric and random sampling, we demonstrate that deterministic processes are more important in shaping the structure of the bacterial community found in types II and III hypolithons. Most notably, the data presented in this study suggest that hypolithic bacterial communities establish via a successional model, with the type I hypolithons acting as the basal development state. Copyright 2013 International Society for Microbial Ecology All rights reserved.AcknowledgementsWe gratefully acknowledge financial support from the following organizations: the National Research Foundation (South Africa), the Research Council of Norway (the South Africa Program; grant no. 180352) and the University of the Western Cape for funding TPM, AV, N-KB and DAC. Logistical support for field research was provided by Antarctica New Zealand and the University of Waikato FRST research project (Understanding, valuing and protecting AntarcticaÅ› unique terrestrial ecosystems: Predicting biocomplexity in Dry Valley ecosystems). We also wish to thank Dr Katharina Besemer (University of Vienna) for providing us with her R script.

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1st AuthorMakhalanyane, T.AuthorMakhalanyane, T.Valverde, A.Birkeland, N.-K.Cary, S.Marla Tuffin, I.Cowan, D.Year2013JournalISME JournalVolume7Number11Pages2080-2090DOI10.1038/ismej.2013.94URLhttps://www.scopus.com/inward/recor.....fb773c9c4a558580b8eac1350Keywordsrank5

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TypeArticleCitationMakhalanyane, T., Valverde, A., Birkeland, N.-K., Cary, S., Marla Tuffin, I. and Cowan, D. (2013). Evidence for successional development in Antarctic hypolithic bacterial communities. ISME Journal, 7(11): 2080-2090 doi:10.1038/ismej.2013.94 IdentifierMakhalanyane2013Relevancerank5

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Cary, S.