A High Arctic soil ecosystem resists long‐term environmental manipulations |
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Authors: | ERIC G LAMB SUKKYUN HAN BRIAN D LANOIL GREG H R HENRY MARTIN E BRUMMELL SAMIRAN BANERJEE STEVEN D SICILIANO |
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Institution: | 1. Department of Plant Sciences, University of Saskatchewan, Saskatoon, SK, Canada S7N 5A8;2. Department of Biological Science, University of Alberta, Edmonton, AB, Canada T6G 2E9;3. Department of Geography, University of British Columbia, Vancouver, BC, Canada V6T 1Z2;4. Department of Soil Science, University of Saskatchewan, Saskatoon, SK, Canada S7N 5A8 |
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Abstract: | We evaluated above‐ and belowground ecosystem changes in a 16 year, combined fertilization and warming experiment in a High Arctic tundra deciduous shrub heath (Alexandra Fiord, Ellesmere Island, NU, Canada). Soil emissions of the three key greenhouse gases (GHGs) (carbon dioxide, methane, and nitrous oxide) were measured in mid‐July 2009 using soil respiration chambers attached to a FTIR system. Soil chemical and biochemical properties including Q10 values for CO2, CH4, and N2O, Bacteria and Archaea assemblage composition, and the diversity and prevalence of key nitrogen cycling genes including bacterial amoA, crenarchaeal amoA, and nosZ were measured. Warming and fertilization caused strong increases in plant community cover and height but had limited effects on GHG fluxes and no substantial effect on soil chemistry or biochemistry. Similarly, there was a surprising lack of directional shifts in the soil microbial community as a whole or any change at all in microbial functional groups associated with CH4 consumption or N2O cycling in any treatment. Thus, it appears that while warming and increased nutrient availability have strongly affected the plant community over the last 16 years, the belowground ecosystem has not yet responded. This resistance of the soil ecosystem has resulted in limited changes in GHG fluxes in response to the experimental treatments. |
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Keywords: | arctic tundra plant community carbon dioxide GHG flux methane nitrogen cycling nitrous oxide soil microbial community |
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