Across-Habitat Comparison of Diazotroph Activity in the Subarctic. Rousk, K., Sorensen, P. L., Lett, S., & Michelsen, A. Microbial Ecology, 69(4):778–787, May, 2015. 00007
Across-Habitat Comparison of Diazotroph Activity in the Subarctic [link]Paper  doi  abstract   bibtex   
Nitrogen (N) fixation by N2-fixing bacteria (diazotrophs) is the primary N input to pristine ecosystems like boreal forests and subarctic and arctic tundra. However, the contribution by the various diazotrophs to habitat N2 fixation remains unclear. We present results from in situ assessments of N2 fixation of five diazotroph associations (with a legume, lichen, feather moss, Sphagnum moss and free-living) incorporating the ground cover of the associations in five typical habitats in the subarctic (wet and dry heath, polygon-heath, birch forest, mire). Further, we assessed the importance of soil and air temperature, as well as moisture conditions for N2 fixation. Across the growing season, the legume had the highest total as well as the highest fraction of N2 fixation rates at habitat level in the heaths (\textgreater85 % of habitat N2 fixation), whereas the free-living diazotrophs had the highest N2 fixation rates in the polygon heath (56 %), the lichen in the birch forest (87 %) and Sphagnum in the mire (100 %). The feather moss did not contribute more than 15 % to habitat N2 fixation in any of the habitats despite its high ground cover. Moisture content seemed to be a major driver of N2 fixation in the lichen, feather moss and free-living diazotrophs. Our results show that the range of N2 fixers found in pristine habitats contribute differently to habitat N2 fixation and that ground cover of the associates does not necessarily mirror contribution.
@article{rousk_across-habitat_2015,
	title = {Across-{Habitat} {Comparison} of {Diazotroph} {Activity} in the {Subarctic}},
	volume = {69},
	issn = {0095-3628, 1432-184X},
	url = {http://link.springer.com/article/10.1007/s00248-014-0534-y},
	doi = {10.1007/s00248-014-0534-y},
	abstract = {Nitrogen (N) fixation by N2-fixing bacteria (diazotrophs) is the primary N input to pristine ecosystems like boreal forests and subarctic and arctic tundra. However, the contribution by the various diazotrophs to habitat N2 fixation remains unclear. We present results from in situ assessments of N2 fixation of five diazotroph associations (with a legume, lichen, feather moss, Sphagnum moss and free-living) incorporating the ground cover of the associations in five typical habitats in the subarctic (wet and dry heath, polygon-heath, birch forest, mire). Further, we assessed the importance of soil and air temperature, as well as moisture conditions for N2 fixation. Across the growing season, the legume had the highest total as well as the highest fraction of N2 fixation rates at habitat level in the heaths ({\textgreater}85 \% of habitat N2 fixation), whereas the free-living diazotrophs had the highest N2 fixation rates in the polygon heath (56 \%), the lichen in the birch forest (87 \%) and Sphagnum in the mire (100 \%). The feather moss did not contribute more than 15 \% to habitat N2 fixation in any of the habitats despite its high ground cover. Moisture content seemed to be a major driver of N2 fixation in the lichen, feather moss and free-living diazotrophs. Our results show that the range of N2 fixers found in pristine habitats contribute differently to habitat N2 fixation and that ground cover of the associates does not necessarily mirror contribution.},
	language = {en},
	number = {4},
	urldate = {2017-02-08},
	journal = {Microbial Ecology},
	author = {Rousk, Kathrin and Sorensen, Pernille L. and Lett, Signe and Michelsen, Anders},
	month = may,
	year = {2015},
	note = {00007},
	keywords = {\#nosource, Boreal forest, Cyanobacteria, Geoecology/Natural Processes, Heterotrophs, Methanotrophs, Microbial Ecology, Microbiology, N deposition, Nature Conservation, Nitrogen fixation, Water Quality/Water Pollution, ecology, subarctic tundra, symbiosis},
	pages = {778--787},
}

Downloads: 0