| Summary: | Shallow freshwater ecosystems are undergoing marked hydrological changes associated with a warming Arctic, which causes concern for remote northern communities that access these regions to maintain their traditional lifestyles. Variation in precipitation patterns (snow and rain), due to changing climate conditions has been found to strongly influence lake water balances. However, knowledge of how such changes in precipitation affect limnology and biotic community structure within lakes is lacking. Working collaboratively with the Vuntut Gwitchin First Nation (VGFN), this thesis examines the influence of hydrology on the limnology of shallow lakes in the Old Crow Flats, Yukon. Relations among source-water composition (snow vs. rain), catchment characteristics, limnology, and sediment properties are assessed and their influence on benthic biota are quantified. Results from 56 lakes, sampled during the early, mid-, and late ice-free season of 2007, identify that catchment mediated differences in source waters (snowmelt-dominated, intermediate and rainfall –dominated) are associated with different limnological characteristics and divergent seasonal trajectories. Snowmelt-dominated lakes, which occur in catchments with tall shrubs and trees, have significantly higher concentrations of dissolved phosphorus and organic carbon, relative to the other categories. These lakes exhibit the least amount of seasonal variation in water chemistry variables. In contrast, rainfall-dominated lakes, which are located in catchments with dwarf shrub and sparse vegetation, have significantly higher concentrations of major ions and higher pH. The rainfall-dominated lakes experience the greatest amount of seasonal variation in water chemistry and tend to be more similar to intermediate lakes in mid- and late-season. Interestingly, seasonal analysis of intermediate lakes highlights sensitivity of these lakes to transitioning sources of input water. As the ice-free season progresses, the water chemistry of intermediate lakes changes from ...
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