Long-term winter ecology and sea ice phenology in subarctic, high-use coastal ecosystems

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The disrupting effects of global change on the structure and function of north-temperate coastal ecosystems, which are widespread throughout Canada, are likely to be manifold. For example, it is expected that the consequences of warming temperatures will be felt rapidly on the dynamics of seasonal sea ice, destabilizing its margins, which are an important habitat for many cold-adapted organisms, and reducing its coverage, thickness, and seasonal duration. These drastic changes could trigger cascading effects like enhancing the strength and duration of stratification of the water column, stimulating eutrophication. Diminishing ice-cover also leaves coastlines more vulnerable to erosion and can boost the intensity of winter maritime activities. This combination of changing environmental conditions and increasing human use of northern coastal regions could negatively impact food webs and enhance infrastructure vulnerability, endangering livelihoods. Furthermore, where port, industrial, and maritime activities occur, pollution can exacerbate these effects. If ecosystem services and livelihoods are to be maintained, policies addressing the sustainable management of these socio-economic activities must rely on a solid scientific understanding of their impacts on the health of coastal environments. Yet baseline and long-term data from which to interpret current environmental conditions and inform science-based management are lacking for northern ports, making it a major challenge to understand the impacts of current global change. There is, therefore, a pressing need to acquire long-term data for this ecosystem type. During the next five years, my research program will focus on developing knowledge about the winter ecology and changing seasonality of sea ice in north-temperate, high-use coasts. Using a novel, multiproxy approach to study the natural archives preserved in coastal sediments, my team and I will generate new, long-term environmental knowledge of broad application to northern ports in Canada and internationally. The region of Sept-Iles, in the Gulf of St-Lawrence, has the second largest deep-water seaport in Canada by yearly tonnage and is home to many heavy industries, including the largest primary aluminum smelter in the Americas. It is an ideal model for testing hypotheses about the functioning of northern port ecosystems and developing innovative methods for their quantitative understanding and management. My research program will therefore initially focus on this region, with the following objectives : 1) To reconstruct past natural variability of winter climatic drivers and their impact on northern coastal ecosystems, and 2) To assess how recent winter-time ecosystem dynamics at the base of the coastal food web are affected by human activities in the context of rapid global change. Ultimately, my team's research will benefit sound, science-based management of high-use coastal ecosystems in Canada and around the circumpolar North.