Functional ecology of plankton: linking lake physical regimes, communities and ecosystem processes

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A major goal of modern ecological research is to improve our ability to predict the response of inherently complex systems to future changes. In an era of rapid change, including climate warming, the urgency to develop such a predictive ability is even more critical so that we can manage natural ecosystems using current and forward-looking knowledge. In lakes, the major effect of climate warming will be to alter thermal regimes, with likely consequences for plankton communities and potentially for lake ecosystem processes as well. In light of the massive environmental changes expected, improving prediction of the responses in ecological structures and functions is essential to the maintenance and management of ecosystem services provided by lakes in the Canadian landscape. A recent approach in ecology for improving the capacity to predict and link communities with ecosystem processes is to use functional traits and their diversity. While there has been intensive work in recent years on the theory and metrics of functional components of community structure, quantitative links with ecosystem processes and critically, the environment in which communities are embedded, has been less clearly made especially under naturally occurring conditions in the field. The Canadian territory includes the majority of the world's lakes and freshwater, providing a unique opportunity and responsibility for Canada's research community to develop a predictive ecology of their functioning. This will better enable researchers and policy makers to advise for lake management given future climate changes, as well as other human-mediated effects on these vital ecosystems.**The research I have proposed will provide quantitative links between lake structure and function, taking into account variation in lake thermal regimes, which alter species interactions. I will focus on lake plankton communities, which are ideal for experimental, observation and trait work because of their small size, fast generation times, high diversity and a long history of lab-based physiological experiments. Moreover, many ecosystem processes, such as primary productivity and transfer of energy and material up the food web in lakes for fish and other vertebrates are highly influenced by the activity of planktonic organisms. The proposed work will link plankton community structure (trait and taxonomic composition, diversity) with ecosystem processes (specific and gross primary and secondary productivity, grazing pressure) by focusing on the role of the environmental effects associated to the physical thermal regimes of lakes and its temporal dynamics. Lake thermal regimes will be among the first affected by climate warming, leading to altered sequences of quiescent versus turbulent periods within and between seasons. **We will use a combination of temporal and spatial observation, including cross-lake analyses, and experimental mesocosms to approach the research questions as these provide both mechanistic insight as well as tests of concepts at larger, whole-lake scales. The research will result in the training of 3 new PhD and 2 new M.Sc. students in aquatic ecology and limnology with expertise in state-of-the art field, laboratory, analytical and statistical methods. As with past personnel, those trained through the completion of this research will go on to contribute nationally and internationally to the study and management of freshwater resources that are increasingly precious as global water quality and quantity become increasingly threatened through anthropogenic and climatic disturbances.