CGRG Bibliography of Canadian Geomorphology
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Author : Balasubramaniam, A.; Hall, R.I.; and Wolfe, B.
Date : 2008.
Title : Developing a framework of baseline data in a complex thermokarst lake system using relationships between hydrological processes and limnological conditions.
Publication : International Arctic Change 2008 Conference. December 9-12, 2008. Quebec City, Quebec.
Issue : Conference Programme and Abstracts
Page(s) : 47-63.
Abstract
The role of hydrological processes on lake ecology is not entirely understood and traditionally is not extensively used in limnological studies. However, in northern shallow lake ecosystems hydrological processes have been found to be a driving force behind biological and chemical changes within the lake. This research uses information gained from stable isotope tracer analysis (d18O and d2H) to assess limnological differences in Old Crow Flats (OCF), Yukon Territory’s most diverse wetland ecosystem recognized under the Ramsar convention of 1982. The OCF, located 75km north of the arctic-circle, contains over 2000 shallow lakes in permafrost terrain. Hydrological processes such as precipitation, evaporation, subsurface flow, surface flow, and melting permafrost have caused these lakes to expand, coalesce and in some cases drain naturally. However, recent observations by the local First Nation report evidence of pronounced and unprecedented hydrological changes (ie. draining and drying of lakes), which are consistent with a warming arctic. The consequences of these hydrological events on chemical and biological processes within lakes is unclear, but is a key linkage to understanding both the ecology of this dynamic lake ecosystem and the associated effects of climate change. A set of 56 lakes spanning hydrological gradients were sampled 3 times over the ice free season of 2007 to assess seasonal relationships between hydrological processes (determined from stable isotope tracers) and water chemistry. Principal Component Analysis (PCA) suggests that hydrological differences among lakes of the Old Crow Flats strongly influence nutrient concentrations. Lakes that receive relatively higher inputs of snowmelt water, as identified by isotopically-depleted lake water compositions, are characterized by high concentrations of phosphorus and dissolved organic carbon. In contrast, lakes that have isotopic signatures suggesting a greater relative influence of rainfall tend to have low concentrations of these nutrients as well as more alkaline pH. Data analysis also suggests that these hydro-limnological relationships remain relatively consistent over the ice free season between June and September. Ongoing analysis of chlorophyll concentrations will determine the effect of hydrological characteristics on biological community composition and associated productivity. These findings indicate hydrological conditions are effective in characterizing limnological patterns in shallow thermokarst lake systems and should be used to develop hydro-limnological baseline data frameworks for long-term monitoring programs.
Bibliography of Canadian Geomorphology