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Diverse and highly active diazotrophic assemblages inhabit ephemerally wetted soils of the Antarctic Dry Valleys.
MedLine Citation:
PMID:  22500944     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Aeolian transport of biomass from ephemerally wetted soils, associated with summer glacial melt-water runoffs and lake-edges, to low productivity areas of the Antarctic Dry Valleys (DV) has been postulated to be an important source of organic matter (fixed-nitrogen and -carbon) to the entire DV ecosystem. However, descriptions and identification of the microbial members responsible for N(2) -fixation within these wetted sites are limited. In this study, N(2) -fixers from wetted soils were identified by direct nifH gene sequencing and their in situ N(2) -fixation activities documented via acetylene reduction and RNA-based quantitative PCR assays. Shannon-index nifH diversity levels ranged from between 1.8-2.6 and included the expected cyanobacterial signatures and a large number of phylotypes related to the gamma-, beta-, alpha- and delta-proteobacteria. N(2) -fixation rates ranged between ~ 0.5 to 6 nmol N cm(-3) h(-1) with measurements indicating that ~ 50% of this activity was linked to sulfate-reduction at some sites. Comparisons to proximal dry soils also suggested that these communities are not ubiquitously distributed, and conditions unrelated to moisture content may define the composition, diversity or habitat suitability of the microbial communities within wetted soils of the DVs. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.
Authors:
Thomas D Niederberger; Jill A Sohm; Joëlle Tirindelli; Troy Gunderson; Douglas G Capone; Edward J Carpenter; S Craig Cary
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-4-16
Journal Detail:
Title:  FEMS microbiology ecology     Volume:  -     ISSN:  1574-6941     ISO Abbreviation:  -     Publication Date:  2012 Apr 
Date Detail:
Created Date:  2012-4-16     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8901229     Medline TA:  FEMS Microbiol Ecol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
© 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.
Affiliation:
College of Marine and Earth Sciences, University of Delaware, Lewes, DE, 19958.
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