Lake sediment records of Arctic ecosystem responses to holocene climatic changes

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The Canadian Arctic is presently undergoing rapid environmental change and the region as a whole is particularly sensitive to climatic change. In order to understand the future impacts of climatic change, and to take measures to mitigate these impacts, a better understanding of Arctic ecosystems is needed. This research program uses paleoecological techniques to investigate the long-term development of both terrestrial and aquatic ecosystems in the Arctic. Paleoecology involves the collection of sediment cores from lakes or wetlands. These sediments have been accumulating for thousands of years and provide an archive of environmental change over long timescales. In our research laboratory, we study microscopic biological remains preserved in these sediment cores. These remains include indicators for paleo-vegetation such as pollen grains or spores, as well as aquatic organisms such as algae, zooplankton and insects. Many of these are well preserved in sediment cores and their identification and study provide detailed records of how ecosystems have changed over time. Taken in conjunction with independently generated paleoclimatic information such as that obtained from ice cores or ocean sediments, the responses of terrestrial and aquatic ecosystems in the Arctic to a variety of climatic changes can be quantified. Therefore, it will be increasingly possible to model the function of ecosystems and to quantify the importance of biological productivity or biodiversity in providing resilience to an ecosystem in the face of environmental changes including climatic changes or other human impacts. The Arctic is a vast region yet there are few studies that have analyzed the long-term development of its terrestrial and aquatic ecosystems. More studies of Arctic ecosystems on long time scales are important because they offer an opportunity to test the universality of ecological models linking disturbance, diversity and resilience, which are frequently generated for temperate or tropical ecosystems.