NWT RESEARCH DATABASE

Tags: physical sciences, oceanography, Beaufort Sea

Objective(s): To recover, service and re-deploy oceanographic moorings carrying instruments that measure ice thickness and ridging, storm waves, sea level, ocean current, temperature and salinity, mammal vocalization, underwater sound and plankton; and, to visit oceanographic stations along the ship's track linking the eastern Beaufort Sea to the Chukchi Sea, measuring fundamental physical and chemical variables from the surface to 500m depth.

Project Description: The strategic objective of this expedition is continued long-term monitoring of Canadian Beaufort Sea. The specific objectives are: 1) to recover, service and re-deploy oceanographic moorings carrying instruments that measure ice thickness and ridging, storm waves, sea level, ocean current, temperature and salinity, mammal vocalization, underwater sound and plankton; and, 2) to visit oceanographic stations along the ship's track linking the eastern Beaufort Sea to the Chukchi Sea, measuring fundamental physical and chemical variables from the surface to 500-m depth. All work is conducted from Canadian Coast Guard Sir Wilfrid Laurier, an 1100-series light icebreaking buoy tender. A “seawater loop” delivers water pumped from just below the sea surface to the main onboard laboratory, where it is sampled continuously to measure its temperature, salinity and the concentrations of dissolved gases (oxygen, carbon dioxide, etc.) and sampled six times daily to measure dissolved nutrients. More comprehensive data are collected at periodic station stops where a temperature-salinity-depth profiling probe (a CTD) is lowered to 500 m depth on a water-sampling rosette. The rosette captures 10-litre volumes of seawater at up to 24 depths. Collected seawater is sub-sampled on board and stored for later analysis of contents for trace seawater components of oceanographic or biological relevance. Oceanographic moorings are to be recovered at 7 sites in the Canadian Beaufort Sea. Oceanographic moorings have been used for year-round observations in the Beaufort Sea since the mid-1970s. The completely submerged moorings consist of a vertical rope connecting a heavy anchor to a float, with electronic scientific instruments attached to the rope that measure and record data on ice thickness and ridging, storm waves, sea level, ocean current, temperature, salinity and plankton density. The instruments recovered each year will have operated autonomously during the last 12 months, recording new data at intervals of 1 second (for ice) or 30-300 minutes (for ocean variables). In the sustained monitoring activity of the Beaufort Marine Hazards and iBO projects, replacement moorings are deployed at the same locations for each subsequent year. This project takes place far out to sea from an icebreaker of the Canadian Coast Guard. In 2016, all available berths on the ship will be occupied either by CCG personnel or by the science team (Department of Fisheries and Oceans Canada plus Natural Resources Canada). There is no opportunity to have local people on board, or even to arrange a shore visit. 2017 or 2018 will be more promising from such engagement. Presentation will be made to the Fisheries Co-Management Committee in Winnipeg or Inuvik, as opportunity permits. Presentation will also be made in Inuvialuit Settlement Region communities, as opportunity permits. The fieldwork for this study will be conducted from September 23, 2016 to October 5, 2016.