"Biogeochemistry of lakes in winter, and the implications of declining ice cover"

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Lakes across much of Canada are ice-covered for long periods every year. Ice cover creates conditions fundamentally different from other seasons, with low light penetration, low temperatures, and the presence of a barrier to gas exchange. Throughout much of the North Temperate Zone we have observed rapid declines in periods of ice cover. Climate change predictions suggest further reductions in ice cover can be expected. However, logistical challenges associated with winter field work mean that we have relatively poor understanding of current conditions in lakes during winter. As a result, prediction of future changes is fraught with uncertainty. The major objective of this proposal is to understand how declining periods of ice cover will affect lake ecology and biogeochemistry. We will use a high frequency autonomous sensor network to measure changes in temperature, light and oxygen concentrations through winter months. We will also perform detailed process-based measurements to understand biogeochemical changes across different lake types. Finally, we will use this new understanding to build models of winter biogeochemistry. This will allow us to predict the ecological and biogeochemical effects of reduced ice cover, and contribute to an improved understanding of how climate change will affect lakes.