Base de données de recherche des TNO

Régions: Inuvialuit Settlement Region

étiquettes: physical sciences, oceanography, marine ecosystem

Objectif(s): To recover, service and re-deploy sub-sea moorings instruments for year-round measurement of ice thickness and ridging, storm waves, sea level, ocean current, temperature and salinity, mammal vocalization, ambient sound and plankton. To complete ocean and seabed surveys near naturally occurring methane vents on the floor of the Beaufort Sea, using echo sounders, ocean-property sensors, samplers and cameras on a tethered submersible. To interpret existing and new data in the context of natural hazards to offshore oil and gas operations from extreme ice and waves, and from seabed instability and oil-well blowout caused by decomposing gas hydrates. To advise government regulators and industry about these risks and their possible mitigation through appropriate methodology and technology.

Description du projet: The objectives of this research project are: - To recover, service and re-deploy sub-sea moorings instruments for year-round measurement of ice thickness and ridging, storm waves, sea level, ocean current, temperature and salinity, mammal vocalization, ambient sound and plankton. - To complete ocean and seabed surveys near naturally occurring methane vents on the floor of the Beaufort Sea, using echo sounders, ocean-property sensors, samplers and cameras on a tethered submersible. - To interpret existing and new data in the context of natural hazards to offshore oil and gas operations from extreme ice and waves, and from seabed instability and oil-well blowout caused by decomposing gas hydrates. - To advise government regulators and industry about these risks and their possible mitigation through appropriate methodology and technology. The Canadian Coast Guard (CCG) annually sends a science-capable icebreaker, CCGS Sir Wilfrid Laurier from Victoria BC, on a multi-tasked voyage to the western Canadian Arctic. Such CCG patrols are the logistical backbone of government marine science in the Arctic. The researchers will use a few days of the Arctic patrol time of CCGS Sir Wilfrid Laurier, in late September and early October, for the scientific exploration described in this licence. This is a fast-moving activity designed to make best use of the hurried homebound transit of CCGS Sir Wilfrid Laurier across the southern Beaufort Sea. The ship's primary tasks are navigational support and search-and-rescue. The researchers will be servicing the sub-sea oceanographic installations (moorings), and conducting surveys on the fly, so as to cause minimal delay in the ship’s schedule. The activities being conducted by the researchers are: - Six oceanographic moorings deployed in 2009 will be recovered from five sites in the Canadian Beaufort Sea. The sub-surface moorings are supporting electronic instruments to measure and record data described on the objectives section above. The instruments 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). - Identical replacement moorings will be deployed at the same locations for continued operation through the period October 2010 through September 2011. The equipment for new moorings was prepared at the Institute of Ocean Sciences before loading to the ship in June. In consequence typical science station time will be about 30 minutes. - A “seawater loop” will continuously deliver water pumped from just below the sea surface to the main onboard laboratory, where it will be sampled to measure temperature, salinity and the concentrations of dissolved gases (methane, oxygen, carbon dioxide, etc.). - While in the vicinity of long-term ocean moorings, a temperature-salinity-depth profiling probe (a CTD) will be lowered to as deep as 1000-m depth on a water-sampling rosette. The rosette will capture 10-litre volumes of seawater at up to 24 depths, from which much smaller volumes will be retained for later chemical analysis to detect trace constituents of oceanographic or biological relevance. - More intensive survey work using conventional oceanographic methods will be conducted in the vicinity of known vents releasing methane at the seabed. The researchers will be sampling seawater on a grid spanning a region of several square kilometres down-drift of each vent chosen for study. They will be operating echo sounders from the ship to detect and map the rising plumes of gas bubble and to determine flow rate of gas at the vents. They will deploy a tethered unmanned submersible vehicle to conduct visual and camera surveys of the gas vents, the plumes rising from them and any associated biologic communities. They will collect mud samples of the seabed at vent sites for later analysis for trapped gas and sediment chemistry. The researchers plan attendance at the NWT IPY Results Conference in Inuvik in February 2011. They have participated in consultation touring groups in the ISR in February 2007 & March 2009 – Paulatuk, Uluhaktok, Sachs Harbour, Tuktoyaktuk, Aklavik & Inuvik – to present research results, answer questions and listen to comments (joining Steve Blasco’s group). The researchers have also produced a brochure, a marine information map, reports (under the project Canada’s Three Oceans), and presented results in public talks and scientific conferences. The fieldwork for this study will be conducted from September 26 to October 02, 2010.