Levinson-Lessing Lake (74 30' N, 98 30' E) on the Taymyr Peninsula, Siberia has been the site of a multi-disciplinary, co-operative research effort since 1993, involving the Alfred Wegener Institute, Germany and the Arctic and Antarctic Research Institute, Russia. This paper reports on the results of a study undertaken in the fall 1995 season, which seeks to quantify nutrient concentrations and distribution in the active layer and upper frozen ground during freeze-back.
The active layer is important in controlling boundary layer processes. Soil moisture dynamics in the active layer are crucial in processes releasing, transporting and yielding nutrients to vegetation, especially in the Arctic where nutrient concentrations can limit plant growth. Bliss et al (1994) identified temperature, soil moisture and soil nutrient availability as controls on plant cover density and species richness. An important time is fall freeze-back, when antecedent conditions for spring growth are set, however, the distribution of nutrients at this time have not been well documented. Previous studies have shown that water migrates towards and into an advancing freezing front (e.g. Harris, 1988) and other theoretical work has predicted the exclusion of solutes from the freezing front (e.g. Hallet, 1988). This field study investigates the movement of soil moisture and solutes during descent of the freezing front through the active layer, thereby linking water and solute processes during a critical time period.
Three sites differing in parent material lithology and microclimate are examined at different stages of freeze-back. Cores of both the active layer and frozen ground were harvested at each site, sliced, frozen and returned to Potsdam, Germany. Soil water samples, soil moisture readings and temperatures were also collected. Profiles of soil moisture, temperature and ionic concentrations of soil water are presented. With the active layer frozen to a depth of only 0.10 m, moisture profiles show an enrichment of total moisture above the frozen front, within the frozen fringe, and a depletion below it. Results from the Siberian cores will be also compared to soil cores retreived at Resolute (74 45' N,94 50'W) and Hot Weather Creek (79 58' N, 84 28' W), sites found in the Canadian Arctic Archipelago.
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Pier P. Overduin York University, Dept. of Geog. 4700 Keele St. North York, Ontario, M3J 1P3 CANADA Telephone: (416) 536-5106 Fax: (416) 736-5988 E-mail: pier@yorku.ca K.L. Young Department of Geography York University 4700 Keele St. North York, Ontario, M3J 1P3 CANADA Phone: (416) 736-5106 E-mail: klyoung@yorku.ca J. Boike Alfred Wegener Institute for Polar and Marine Science Telegrafenberg A43, 14473 Potsdam GERMANY E-mail: jboike@awi-potsdam.de H. Welch 501 University Avenue Winnipeg, Manitoba, R3T 2N6 CANADA M.-K. Woo Geography Department McMaster University Hamilton, Ontario, L8S 4K1 CANADA