Hudson Bay System Study (BaySys)

BaySys provided a scientific basis to separate climate change effects from those of hydroelectric regulation of freshwater on physical, biological, and biogeochemical conditions in Hudson Bay. This overall project objective was addressed through a 'systems' perspective. The project was divided into six teams of researchers, with each examining climate change and regulation from a different perspective. The six teams were:

1. Marine/climate systems
2. Freshwater
3. Marine ecosystem
4. Carbon cycling
5. Contaminants
6. Ocean Modelling

Marine/climate systems

The marine/climate systems team worked to understand how changes in climate variability and hydroelectric regulation affected processes related to light, heat and momentum exchange, between the freshwater, marine, sea ice, and atmospheric systems. They then examined how these processes have manifested changes in the physical properties and distribution of water masses in Hudson Bay.

Freshwater

To understand the relative impact of regulation and climate change to the Hudson Bay Complex, the freshwater team investigated the role of freshwater timing and magnitude on contemporary and future projections of freshwater-marine coupling in Hudson Bay. The team did this by developing continental-scale modelling of the entire Hudson Bay watershed. They conducted uncertainty assessments on the model and projected net changes to runoff under climate, regulation, and naturalized conditions. Results from this team were integral to the ability of other teams to evaluate the impacts of climate change and hydroelectric regulation on the physical, biological, and biogeochemical processes in the bay.

Marine ecosystem

Team 3 had two objectives. First, to assess how different drivers collectively affect biological productivity. Second, the team studied the diversity and interactions of water column organisms (microbes, algae, and consumers) and the benthos (the community of organisms that live on, in or near the bottom of the ocean). This allowed the ecosystem team to identify the pathway of nutrients entering Hudson Bay through marine gateways in regulated versus unregulated rivers.

Carbon cycling

The carbon cycling team focused on the role of freshwater in moderating the carbon system of Hudson Bay. This ultimately led to increasing our understanding of carbon cycling and Hudson Bay's current and future role as a carbon dioxide source/sink derived from multi-season analysis.

Contaminants

Mercury is one of the primary contaminants of concern associated with hydroelectric regulation due to enhanced mercury methylation in flooded reservoirs and wetlands. The contaminants team's goal was to examine how contaminant transportation and transformation in the Hudson Bay ecosystem responded to regulation and a changing climate.

Ocean modelling

Ocean modelling became its own team in the second year of the project to ensure the large-scale ocean modelling component could be completed and integrated into the rest of the study. Their objectives were to investigate the relative impacts of climate change and regulation on freshwater-marine coupling within the Hudson Bay System from a modelling perspective. Their other goals were to provide an integrated observational-modelling freshwater/marine framework for model-data comparison, to improve the understanding of physical mechanisms responsible for observed phenomena based on observations and historical simulations, and to improve representation in future simulations.