Application of anifHmicroarray to assess the impact of environmental factors on free-living diazotrophs in a glacier forefield
Glacier forefield environments are exposed to extreme and fluctuating climatic and nutritional conditions. The high diversity of free-living diazotrophic communities found in these environments indicates that nitrogen fixers are able to efficiently cope with such conditions. In this study, a nifH mi...
Published in: | Canadian Journal of Microbiology |
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Main Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Canadian Science Publishing
2011
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Subjects: | |
Online Access: | http://dx.doi.org/10.1139/w10-100 http://www.nrcresearchpress.com/doi/full-xml/10.1139/W10-100 http://www.nrcresearchpress.com/doi/pdf/10.1139/W10-100 |
Summary: | Glacier forefield environments are exposed to extreme and fluctuating climatic and nutritional conditions. The high diversity of free-living diazotrophic communities found in these environments indicates that nitrogen fixers are able to efficiently cope with such conditions. In this study, a nifH microarray was used to monitor changes in diazotrophic populations in the field over a season, in the presence or absence of plants and in 2 glacier forefields characterized by a different bedrock type (siliceous or calcareous), as well as at different temperatures (10 °C, 15 °C) and under different nitrogen fertilization regimes (0, 10, 40 kg N·ha –1 ·year –1 ) in laboratory systems. Population structures responded highly dynamically to environmental changes. Plant presence had the strongest impact, which decreased toward the end of the season and with high amounts of nitrogen fertilization. Temperature and nitrogen fertilization increases indirectly affected diazotrophic communities through their positive impact on plant growth. These results indicate strong carbon limitation in young glacier forefield soils. Phylotypes related to the genus Methylocystis strongly responded to environmental variations. These methanotrophic microorganisms, which are able to retrieve nitrogen and carbon from the atmospheric pool, are particularly adapted to the extreme nutritional conditions found in glacier forefields. |
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