CGRG Bibliography of Canadian Geomorphology
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Author : Dobson, E.; Wolfe, B.B.; Macrae, M.L.; Hall, R.I.; and Duguay, C.R.
Date : 2009.
Title : Paleohydrological reconstruction of tundra pond water balance from lake sediment records (Churchill, Manitoba).
Publication : Communities of Change - Building an IPY Legacy. 9th ACUNS International Student Conference on Northern Studies and Polar Regions. October 2-5, 2009. Whitehorse, Yukon.
Issue : Book of Abstracts.
Page(s) : 134.
Abstract
The Hudson Bay Lowland (HBL) is the largest peat basin in North America and is one of most extensive sub-arctic wetlands in the world. Shallow tundra ponds are an important feature, occupying at least 20 percent of the landscape in the Churchill region of northern Manitoba. These ponds provide habitat for wildlife, particularly nesting waterfowl. Some recent work has suggested that high latitude water bodies are drying which will have important ecological consequences. However, other studies argue that these landscapes will become wetter under a changing climate. Many examinations of pond permanence have relied extensively on imagery analysis but are confounded by uncertainties in the effects of intra-seasonal climate variability on pond surface area. Furthermore, these approaches are constrained by data that span a limited duration, which typically encompass the latter half of the twentieth century. A longer temporal perspective of hydrological variability is required to anticipate how these landscapes will evolve under a warmer climate. The objective of this research is to answer the following questions: Has the hydrologic budget of ponds in the HBL responded to recent climate warming? If so, is this unprecedented or a natural feature of hydrologic variability of the past several hundred years? Records of hydrologic variability over the past several hundred years will be obtained from analysis of lake sediment cores collected from several ponds in the Churchill region. Sediment cores will be secured in the summer of 2009 using a conventional gravity corer and sectioned at 0.5 cm intervals for multi-proxy analyses. Sediment core chronologies will be established using standard radiometric techniques (137Cs, 210Pb, 14C). Paleohydrological reconstructions will be based on analyses of bulk organic carbon and nitrogen elemental isotope composition, and cellulose oxygen isotope composition. Sediments in many of the ponds are >90% organic, which is highly conducive to these geochemical techniques. Isotopic monitoring of the cored ponds will provide key constraints to the reconstructions of pond water oxygen isotope history. These findings will provide key knowledge for predicting the future hydrologic response of this ecosystem to ongoing climate change.
Bibliography of Canadian Geomorphology