Microbial community composition plays a vital role in soil biogeochemical cycling. Information that explains the biogeography of microorganisms is consequently necessary for predicting the timing and magnitude of important ecosystem services mediated by soil biota, such as decomposition and nutrient cycling. Theory developed to explain patterns in plant and animal distributions such as the prevalent relationship between ecosystem productivity and diversity may be successfully extended to microbial systems and accelerate an emerging ecological understanding of the "unseen majority." These considerations suggest a need to define the important mechanisms which affect microbial biogeography as well as the sensitivity of community structure/function to changing climatic or environmental conditions. To this end, my dissertation covers three data chapters in which I have 1) examined patterns in bacterial biogeography using gradients of environmental severity and productivity to identify changes in community diversity (e.g. taxonomic richness) and structure (e.g. similarity); 2) detected potential bacterial ecotypes associated with distinct soil habitats such as those of high alkalinity or electrical conductivity and; 3) measured environmental controls over the function (e.g. primary production, exoenzyme activity) of soil organisms in an environment of severe environmental limitations. (Abstract shortened by ProQuest.)
|Advisor:||Barrett, John E.|
|School:||Virginia Polytechnic Institute and State University|
|School Location:||United States -- Virginia|
|Source:||DAI-B 78/09(E), Dissertation Abstracts International|
|Subjects:||Ecology, Microbiology, Soil sciences|
|Keywords:||Antarctica, Biogeochemistry, McMurdo dry valleys, Microbial ecology, Productivity-diversity theory|
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