Nitrogen fixation in the high arctic tundra at Sarcpa Lake, Northwest Territories

• Published in: Canadian Journal of Botany
• Main Authors: Karagatzides, Jim D., Lewis, Martin C., Schulman, Herbert M.
• Format: Article in Journal/Newspaper
• Language: French
• Published: Canadian Science Publishing 1985
• Subjects: Plant Science; Arctic; Northwest Territories; Sarcpa Lake; Tundra
• Online Access: http://dx.doi.org/10.1139/b85-131; http://www.nrcresearchpress.com/doi/pdf/10.1139/b85-131

The acetylene reduction assay was used to examine biological nitrogen fixation in the high arctic tundra at Sarcpa Lake, Northwest Territories (68°32′ N, 83°19′ W). The highest rates of acetylene reduction (9.37 ± 3.19 μmol C 2 H 4 m −2 h −1 ) were in habitats that had a high density of the legumes Oxytropis maydelliana, O. arctobia, and Astragalus alpinus. Nitrogen fixation in the wet soils along the shore of a small lake was similar (8.87 ± 4.35 μmol C 2 H 4 m −2 h −1 ) because of the blue-green alga Nostoc, which associates with mosses. Free-living blue-green algae and lichens made insignificant contributions to the total nitrogen fixation budget because they were uncommon and fixed nitrogen at a slower rate. Nitrogen-fixing lichens in the area included Stereocaulon arenarium and S. rivulorum. It is concluded that legumes have a significant input to the biological nitrogen fixation budget at Sarcpa Lake.