VENUS provides opportunities to conduct oceanographic research in two rich marine environments.
Saanich Inlet is a deep, silled fjord with limited water exchange into the deeper reaches. Biological consumption of oxygen introduces anoxic conditions below 100m. VENUS instruments records environmental, microbial, and animal community interactions in this vertically structured setting.
The Strait of Georgia is a large, deep, inland basin that is strongly influenced by wind, tide, and river discharge.
Seasonal variations in the physical, chemical, and biological environments are significant, and the permanent monitoring of the marine conditions provide a valuable baseline for various research interests. Research projects include the following:
The shallow sill at the north end of Saanich Inlet acts as a barrier between the dense, oxygen-rich waters of Satellite Channel to the north and the deep, stagnant waters within the central reaches of Saanich Inlet. Strong spring plankton blooms reflect seasonal changes in available nutrients. However, microbial decay of plankton depletes oxygen in the bottom waters of the Inlet, often causing natural hypoxia.
Dense populations of zooplankton and fish respond to conditions in the Inlet that change throughout the year. Studies of the temporal variations in the vertical distribution of oxygen and nutrients and the response of various biological communities to these variations will be monitored by network sensors.
The Strait of Georgia and Saanich Inlet both support interesting and complex benthic communities of marine life.
Saanich Inlet provides an excellent setting to examine the interaction of animals with sediments; the presence of anoxic conditions close to dense benthic assemblages provides an opportunity for comparative experiments. Plankton and fish interact with the bottom in quiet waters. In the Strait of Georgia, high sedimentation from the Fraser River and strong currents affect the colonization of new surfaces. Cameras and specialized sensors will monitor the interactions at the ocean bottom. Principal scientists include Paul Snelgrove, Anna Metaxas, and Kim Juniper.
The coastal waters of British Columbia are populated by numerous fish and marine mammals, including salmon, herring, seals, sea lions, and orcas or killer whales. Understanding the migration patterns and tendencies of these high trophic level species in a core research theme of VENUS. Both active and passive acoustic systems help monitor the distribution and abundence of fish and marine mammals.
VENUS, in collaboration with the Institute and Ocean Sciences (Svein Vagle) and the Pacific Biological Station (John Ford) have developed an acoustic hydrophone array for monitoring marine mammal behaviour. Arrays have been deployed in both Saanich Inlet and the Strait of Georgia. Of central interest is to better understand communications within and between whale pods in a setting with abundant ship noise.
The Fraser River, the largest in British Columbia, empties into the eastern edge of the Strait of Georgia. The river strongly influences the environmental conditions within the Strait. Silt and sediment transported down the river settle in the delta region where containment structures influence sedimentation patterns. The freshet, which peaks in June, is sourced by snow melt in the coastal mountains and introduces a significant volume of fresh water into the Strait and the coastal waters of B.C.
This constant sediment loading makes the delta and slope regions both dynamic and potentially unstable. As part of VENUS, a dedicated suite of instruments will be deployed along the rim of the delta to monitor and measure the near-bottom sediment conditions. Phil Hill of the Pacific Geological Centre is leading this research project.
The coastal waters of British Columbia are subject to vigorous currents, driven by buoyancy (density differences), wind, and tides.
Circulation, waves, and mixing in the Strait of Georgia strongly influence the distribution of heat, salt, and nutrients. Currents and water density also affect conditions in Saanich Inlet, including those associated with deep-water renewal of oxygen-rich water over the shallow sill.
Instruments deployed at each VENUS node monitor both the scalar water properties (temperature, conductivity, and oxygen concentration) and the ocean currents. Such data can be used broadly to test general models of estuarine-driven circulation.