Spatially tripartite interactions of denitrifiers in arctic ecosystems: activities, functional groups and soil resources
Article first published online: 4 JUL 2012
© 2012 Society for Applied Microbiology and Blackwell Publishing Ltd
Special Issue: Microbial Communities - Structure, Behaviour, Evolution
Volume 14, Issue 9, pages 2601–2613, September 2012
How to Cite
Banerjee, S. and Siciliano, S. D. (2012), Spatially tripartite interactions of denitrifiers in arctic ecosystems: activities, functional groups and soil resources. Environmental Microbiology, 14: 2601–2613. doi: 10.1111/j.1462-2920.2012.02814.x
- Issue published online: 4 SEP 2012
- Article first published online: 4 JUL 2012
- Accepted manuscript online: 12 JUN 2012 12:01AM EST
- Received 28 June, 2011; revised 11 May, 2012; accepted 14 May, 2012.
Soil denitrification is one of the most significant contributors to global nitrous oxide (N2O) emissions, and spatial patterns of denitrifying communities and their functions may reveal the factors that drive denitrification potential and functional consortia. Although denitrifier spatial patterns have been studied extensively in most soil ecosystems, little is known about these processes in arctic soils. This study aimed to unravel the spatial relationships among denitrifier abundance, denitrification potential and soil resources in 279 soil samples collected from three Canadian arctic ecosystems encompassing 7° in latitude and 27° in longitude. The abundance of nirS (106–108 copies g−1 dry soil), nirK (103-107 copies g−1 dry soil) and nosZ (106–107 copies g−1 dry soil) genes in these soils is in the similar range as non-arctic soil ecosystems. Potential denitrification in Organic Cryosols (1034 ng N2O-N g−1 soil) was 5–11 times higher than Static/Turbic Cryosols and the overall denitrification potential in Cryosols was also comparable to other ecosystems. We found denitrifier functional groups and potential denitrification were highly spatially dependent within a scale of 5 m. Functional groups and soil resources were significantly (P < 0.01) correlated to potential denitrifier activities and the correlations were stronger in Organic Cryosols. Soil moisture, organic carbon and nitrogen content were the predominant controls with nirK abundance also linked to potential denitrification. This study suggests that the dominant control on arctic ecosystem-level denitrification potential is moisture and organic carbon. Further, microbial abundance controls on ecosystem level activity while undoubtedly present, are masked in the nutrient-poor arctic environment by soil resource control on denitrifier ecosystem level activity.