Impacts of active retrogressive thaw slumps on vegetation, soil, and net ecosystem exchange of carbon dioxide in the Canadian High Arctic

• Main Authors: Cassidy, Alison Elizabeth, Christen, Andreas, Henry, Greg
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: NRC Research Press (a division of Canadian Science Publishing) 2017
• Subjects: Arctic; Canada; Ellesmere Island; Fosheim Peninsula; permafrost; Tundra
• Online Access: http://hdl.handle.net/1807/77091; http://www.nrcresearchpress.com/doi/abs/10.1139/AS-2016-0034

Retrogressive thaw slumps (RTS) are permafrost disturbances common on the Fosheim Peninsula, Ellesmere Island, Canada. During the 2013 growing season, three different RTS were studied to investigate the impact on vegetation composition, soil, and growing season net ecosystem exchange (NEE) of carbon dioxide (CO2) by comparing to the adjacent undisturbed tundra. Eddy covariance (EC) and static chamber measurements were used to determine NEE and ecosystem respiration (Re), respectively. Vegetation cover was significantly lower in all active disturbances, relative to the surrounding tundra and this affected the overall impact of disturbance on CO2 fluxes. Disturbances were characterized by greater Re compared to surrounding undisturbed tundra. Over the mid-growing season (34 days), EC NEE measurements indicated there was greater net CO2 uptake in undisturbed vs disturbed tundra. Two of the RTS exhibited average soil temperatures that were greater compared to the surrounding undisturbed tundra. In one case the opposite effect was observed. All RTS exhibited elevated soil moisture (+14 %) and nutrient availability (specifically nitrogen) relative to the undisturbed tundra. We conclude that RTS, although limited in space, have a profound environmental impacts by reducing vegetation coverage, increasing wet soil conditions, and alter NEE during the growing season in the High Arctic. The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author.