Effects of a ten-year climate warming experiment on nitrogen cycling in high arctic tundra ...

• Main Author: Rolph, Sandra Gale
• Format: Text
• Language: English
• Published: University of British Columbia 2009
• Subjects: Alexandra Fiord; Arctic; Ellesmere Island; Tundra
• Online Access: https://dx.doi.org/10.14288/1.0090983; https://doi.library.ubc.ca/10.14288/1.0090983

The effects of a 10-year climate warming experiment on nitrogen (N) cycling in high arctic tundra ecosystems were examined along a soil moisture gradient at Alexandra Fiord, Ellesmere Island, Canada (78°53'N, 75°55'W). Open top chambers were established in 1992 to passively warm five tundra plant communities within the range predicted for a doubling of atmospheric CO₂. Inorganic N availability, measured using ion exchange membranes, was consistently higher in the warmed plots throughout the growing season in three plant communities. Soluble organic N availability increased significantly with warming in a wet sedge meadow. Net N mineralization in buried bag incubations was not significantly affected by the warming treatments; however, net N immobilization was four-times higher in the warmed plots compared to the controls in the sedge meadow. Reciprocal transplantation of buried bags between temperature treatments indicated that the increase in net N immobilization was a result of changes in soil properties ...