The Southampton Island Marine Ecosystem Project, 2019 Cruise Report, 2-29 August, MV William Kennedy
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Date
2019
Authors
Mundy, C.J.
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Abstract
Climate warming is forcing rapid change to Canada’s marine Arctic icescape (Hochheim and Barber 2010) and its associated ecosystem, while the increasing ice-free season is supporting an ever-increasing industrial presence in the North. With over two-thirds of Canada’s coastline being located in the North and the fact that nearshore waters represent some of the most productive Arctic regions, there is a need to improve our understanding of marine ecosystem processes in the sensitive Arctic coastal zone. The marine region around Southampton Island, northwest Hudson Bay (Nunavut), encompasses one of Canada’s largest summer and winter aggregations of Arctic marine mammals, providing multiple ecosystem services. This biological hotspot has supported local human habitation for millennia with confirmed Dorset, Thule, and Sadlermiut occupation sites (Collins 1956; Clark 1980; McGhee 1970), and is still crucial to the subsistence economy of local communities today. The region has also been a marine mammal management focus of Fisheries and Oceans Canada (DFO) for decades and supports two sea bird sanctuaries, yet we know surprisingly little of the region’s oceanography, productivity or biological community below these top trophic levels. This fact highlights a major management risk, severely limiting our ability to understand and predict changes to this unique and productive marine ecosystem. Exacerbating this risk are pressures posed by the ongoing climate changes and an increasing industrial presence. Therefore, we undertook an oceanographic study called the Southampton Island Marine Ecosystem Project (SIMEP), funded by the MEOPAR Network of Centres of Excellence (NCE).
The SIMEP network assumes a bottom up driven ecosystem, hypothesizing that the enhanced biological productivity can be explained by: 1) Winter pre-conditioning of surface waters associated with large polynyas that form along the western coasts of Foxe Basin and Hudson Bay. Also known as ice factories, these polynyas produce dense salty brine that can sink, ventilating deeper waters while associated mixing replenishes surface nutrients and therefore, primary production. 2) Tidal and wind-driven mixing along shallow nearshore as well as shoaled and constricted waterways of Roes Welcome Sound, Frozen Strait and Fisher Strait. Some of the world’s largest tides are observed in Hudson Bay and as they move water back and forth across these areas, currents and mixing intensify, increasing water mass exchange and thus nutrient supply in the area. 3) East and north of Southampton Island, water masses originating in the Atlantic (via Hudson Strait) and Pacific (via Foxe Basin) Ocean are mixed and modified, and greatly influence production as large inventories of new nutrients are imported to the region (Harvey et al. 2006; Ferland et al. 2011). To test these hypotheses, we assembled a network of university and government scientists seeking to obtain a food web-based understanding of the ecosystem.
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Keywords
Arctic, Southampton Island, marine ecology, macrophytes, phytoplankton, zooplankton, invertebrates, fishes, biogeochemistry, oceanography, hydrography, taxonomy, marine sediments, surface sediments