Southeast and northwest coastal Hudson Bay water salinity, oxygen isotope, and nutrient data

The objective of this study was to develop a greater understanding of freshwater sources in coastal areas of northwest and southeast Hudson Bay, as well as to discuss the dynamics of nutrients and how specific water types influence nutrient distributions. The two coastal regions that are the focus of this study are northwest Hudson Bay (NWHB), including sub-regions Naujaat and Chesterfield Inlet, and southeast Hudson Bay (SEHB), including the sub-regions Sanikiluaq, Kuujuaraapik, Umiujaq, and Inukjuak. We present new nutrient and freshwater tracer data for water samples collected during ice-covered conditions for both regions. Our aim is to test the hypothesis that, despite having the same source seawater, excess river water in winter in coastal SEHB leads to more limited nutrient recharge compared to the ice-dominated NWHB, which is a productive hotspot in spring. The winter SEHB coastal water mass is largely influenced by riverine input from local rivers (Great Whale River and the Nastapoca River), but also from the upstream James Bay outlet and has an average salinity of 26.