NWT RESEARCH DATABASE

Regions: Inuvialuit Settlement Region

Tags: physical sciences, bathymetry, habitat, sonar survey, seabed

Objective(s): The objective of the seabed mapping program is to conduct a regional survey of the Beaufort shelf over the next two years. Ice scouring processes, benthic habitats, abandoned artificial islands, pingo-like features, gas seeps, seafloor foundation conditions, subsea permafrost and coastal stability will be investigated.

Project Description: The objective of the seabed mapping program is to conduct a regional survey of the Beaufort shelf over the next two years. Ice scouring processes, benthic habitats, abandoned artificial islands, pingo-like features, gas seeps, seafloor foundation conditions, subsea permafrost and coastal stability will be investigated. The Coast Guard vessel CCGS Nahidik will be used as the research platform to collect seabed sediment samples and bottom photographs and to conduct offshore acoustic/sonar surveys of the seabed. Specific sites as well as a regional grid of survey lines first surveyed in the 1980’s, will be resurveyed as follows: a) use a 300kHz short range multibeam echo sounder (Simrad EM 3000) to produce 200m wide along track maps of the topography and character of the seabed. Additional multibeam data will be collected at specific sites on the central shelf. The multibeam system is operated from a 9m long survey launch deployed daily from the Nahidik. b) use a 100 kHz sidescan sonar (Klein 595) to map the distribution of ice scours on the seabed for comparison to historic data and to calibrate the multibeam data. c) use a single beam 200 kHz echo sounder to map the depths of ice scours on the seabed and to calibrate the multibeam sonar. d) use 1.0-3.5 kHz subbottom profilers (boomer, sparker) to map the distribution of sediments to 100m below seabed at specific sites (mud volcanoes, gas vents, artificial island, permafrost, habitat sites). e) use a drop camera and a bottom towed video camera to photograph the nature of the seabed and benthic habitat. f) collect sediment grab samples and sediment cores of the upper 2 m of seabed to provide sample control to calibrate the multibeam sonar and video camera data. It is anticipated that about 80-100 seabed samples will be recovered for analysis each year. Sea-ice and sea-state conditions and the distribution of marine mammals will control the access to research sites on the shelf in any one year. Over the 4-year survey period it is anticipated that all critical areas and features will have been surveyed. The seabed sampling phase of the Nahidik program will be mobilized out of Inuvik in late July. The vessel will then conduct the sampling program offshore until August 26. The Nahidik will then return to Inuvik to mobilize multibeam/subbottom survey personnel and equipment. This phase will be conducted offshore from August 26 –September 22. Personnel and limited equipment will be demobilized in Tuktoyaktuk September 20. The Nahidik will return to Inuvik and personnel will depart the ship by September 22. This project conducts annual consultation with each of the 6 communities. For example, in February and March 2007, a team of Nahidik scientists met with members of the HTC's in Inuvik, Aklavik, Tuktoyaktuk, Sacks Harbour, Paulatuk and Ulukhatok to present the results of the 2006 research program, discuss plans for 2007 and beyond and to solicit TK input into research activities. Fieldwork will be conducted from July 25 to September 22, 2007 at the Canadian Beaufort continental shelf, bounded by 131°00' to 141°00' West longitude and 69°30' to 71°00' North latitude. Exact locations to be surveyed on the shelf in any one year are dependent on weather and sea-ice conditions as the vessel is not ice strengthened.