ИСТИНА

Hudson Bay has the largest freshwater drainage basin in Canada. Several of the main river outlets that discharge into both Hudson and James Bay are now regulated for the purpose of generating hydroelectricity. This development has led to a dramatic change in the seasonal peaks of freshwater runoff, from late spring to mid-winter. The Belcher Islands in southeast Hudson Bay are downstream from most of the freshwater runoff introduced into the Hudson and James Bay systems. This area is also known for its numerous polynyas, which play a significant role as winter habitat for birds (such as the common eider) and marine mammals (beluga). Inuit from Sanikiluaq travel and hunt in the area extensively. Because polynyas are ‘ice factories’ (or ‘negative estuaries’), increased amounts of freshwater in these areas in winter have the potential to disturb several important processes, such as reducing the depth of winter mixing, which controls the replenishment of nutrients into surface waters, or impacting the formation of deep water. The presence of freshwater may also alter the rate of formation or properties of sea ice. During the last decade, community members of Sanikiluaq have raised concerns that the polynyas have been freezing up more rapidly, causing distress for the wildlife that rely on this seasonal habitat. In collaboration with the Arctic Eider Society, they have begun gathering traditional knowledge and visual documentation about the environmental conditions. However, scientific data about freshwater distribution and polynya processes in southeast Hudson Bay are scarce. In January-March 2014, we joined the collaboration with the Arctic Eider Society and Sanikiluaq. A mooring containing several temperature and salinity (CT) sensors and two current profilers was installed from the landfast ice southeast of the Belcher Islands and additional CT sensors were deployed beneath the ice at various other locations around the islands. CTD casts and water and ice-core sampling were conducted at various sites. The water samples were analyzed for salinity, oxygen isotope ratios (δ18O), and CDOM, to quantify the amount and components of the freshwater present (river runoff vs. sea ice formation/melt). Ice core records of δ18O were used to derive a record of freshwater distribution throughout the period of ice cover. Collectively, these data points begin to establish a baseline for winter oceanographic conditions and the freshwater budget in southeast Hudson Bay. We hope to expand this research to a larger network of sites in the coming years.