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32nd Annual Arctic Workshop Abstracts
March 14-16, 2002
INSTAAR, University of Colorado at Boulder

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IMPACTS OF CLIMATE CHANGE ON NITROGEN FIXING MICROBIAL COMMUNITIES IN THE CANADIAN HIGH ARCTIC

AUTHORS

DESLIPPE, JULIE R. University of Northern British Columbia.
Egger, Keith N. University of Northern British Columbia.

Many terrestrial arctic ecosystems are strongly nitrogen limited. Nitrogen-fixing bacteria (diazotrophs) are important regulators for plant productivity at these sites. Global warming may alter selective pressure on bacterial communities causing changes in bacterial diversity and community structure and resulting in sustained alteration of the nitrogen budget for plants. The objectives of my research are to examine the diversity and community structure of diazotrophic communities under conditions of simulated climate change in the Canadian high arctic and to examine nitrogen inputs from the communities. A nested PCR protocol will be used to amplify nifH gene sequences from bulk DNA extracted from soils of warmed and fertilised plots from a mesic site at Alexandra Fiord, Ellesmere Island, Nunavut. Terminal restriction fragment length polymorphisms (T-RFLPs) will be used to analyse the diversity of nifH gene sequences from each treatment. Concurrently, measurements of nitrogen fixation will be made by the acetylene reduction and the 15N methods. NifH gene diversity will be related to the rate of nitrogen fixation.

 

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