| Summary: | Lakes are abundant in the terrestrial arctic, extending over about one quarter of the territory. For approximately nine months of the year, the waters of arctic lakes are under ice. Despite the duration of the ice-covered period, few studies have addressed the limnology (biological, chemical, and physical features) of these lakes during winter and how conditions under ice affects the stratification of lakes during the summer. We aim to look at the full year cycle lake circulation in order to quantify the effects of hydrodynamics on nutrient and gas fluxes and place the results within the context of climate change in the Arctic. The goals of our study include: (1) quantifying physical and biogeochemical controls on under ice thermal structure and circulation, the flowpath of snow melt, and mixing during spring and fall (2) quantifying respiration rates in arctic lakes of differing morphology and on geological substrates (3) illustrating the linkages and feedbacks between these physical and biogeochemical processes. Our research is being conducted in lakes studied by the Arctic Long Term Ecological Research (ARC LTER). The selected lakes are: Toolik Lake, Lake E1, Lake E5, Lake E6 and Lake N2. The Lakes range in size from 1 to 1500 hectares. Time series of water temperatures, specific conductance and dissolved oxygen at several depths were obtained from a taut-line mooring in different seasons (summer and winter) across multiple years (between fall 2012 and fall 2016).
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