The Great Whale River ecosystem: ecology of a subarctic river and its receiving waters in coastal Hudson Bay, Canada

Abstract

The Great Whale River in subarctic Quebec, Canada, is one of the main freshwater inflows to Hudson Bay. This region is experiencing rapid climate change, with pronounced impacts on the cryosphere, and ongoing socio-economic development that may accelerate with future road and shipping links. This review integrates information available to date on the Great Whale River ecosystem, which we define as the river and its watershed, its source lakes and streams, and the river mouth environment and beyond the shoreline in southeastern Hudson Bay. Our aim was to define the current state of this ecosystem as a baseline for ongoing observations, with emphasis on (1) the distribution of water masses, optical characteristics, freshwater discharge, and ice cover; (2) concentrations and fluxes of carbon, nutrients, and contaminants; (3) abundance, production and diversity of the organisms associated with the sea ice ecosystem; (4) plankton abundance, biomass, production, and assemblages; (5) benthic abundance and diversity; (6) fish abundance, diversity and population dynamics; (7) marine mammal biology; and (8) global change impacts on freshwater and marine habitats. This synthesis provides a first step towards the integrated management of the Great Whale River ecosystem, and for similar freshwater-marine systems in the subarctic region.

Size-Fractionated Microbiome Structure in Subarctic Rivers and a Coastal Plume Across DOC and Salinity Gradients

“…There was a downstream increase in TSS along the GWR transect (especially at site G6) that may indicate decreased landscape stability and increased erosion in the lower reaches of the river. Geomorphological analysis of the downstream river channel shows evidence of increased recent landslide activity, possibly linked to increasing extreme rainfall events ( Owczarek et al, 2020 ), and a major landslide occurred 8 km upstream from the river mouth in April 2021 ( Nozais et al, 2021 ). There was a further upshift in TSS between the most downstream freshwater sites (G7, G8) and the plume in coastal Hudson Bay, which may be the result of tidal resuspension of shallow sediments ( Ingram, 1981 ), as well as flocculation of particles induced by the mixing with saline waters ( Mosley and Liss, 2020 ).…”

“…This small river passes through a valley of degrading palsa mounds and associated thaw lakes ( Arlen-Pouliot and Bhiry, 2005 ; Figure 7 in Vincent et al, 2017 ), and discharges into Hudson Bay approximately 1 km southwest of the mouth of the GWR. Additional background information about the GWR and its associated landscapes and marine coastal habitats is given in Nozais et al (2021) .…”

Kelp in the Eastern Canadian Arctic: Current and Future Predictions of Habitat Suitability and Cover

“…In general, James Bay was not predicted to provide suitable habitat for any of the modeled kelp species, which may be explained by the particularities of the region relative to the rest of the assessment area. James Bay is characterized by considerable freshwater runoff from the surrounding land mass, together with a great amount of river borne sediments, with mud bottoms dominating most of the bay (Stewart and Lockhart, 2005;Nozais et al, 2021). It is generally shallow (rarely deeper than 50 m) and has historically had vast subtidal meadows of eelgrass, Zostera marina, along its coastlines (Stewart and Lockhart, 2005).…”

Diverse winter communities and biogeochemical cycling potential in the under-ice microbial plankton of a subarctic river-to-sea continuum

“…The river is ice covered more than 6 months of the year [from approximately late November to mid-May; ( 16 )]. During this period, the river discharge is reduced, with a minimum in April [200 vs 910 m 3 s −1 at peak flow in June; ( 17 , 18 )]. The Great Whale River watershed has been widely studied and is viewed as a model system for isolated/sporadic permafrost and a sentinel for global change ( 18 ).…”

“…During this period, the river discharge is reduced, with a minimum in April [200 vs 910 m 3 s −1 at peak flow in June; ( 17 , 18 )]. The Great Whale River watershed has been widely studied and is viewed as a model system for isolated/sporadic permafrost and a sentinel for global change ( 18 ). More recently, the microbial communities of the river and its plume during the summer season ( 19 , 20 ) have been examined, and these results showed strong gradients in community structure across the freshwater-saltwater transition.…”