Base de données de recherche des TNO

Régions: Inuvialuit Settlement Region, Gwich'in Settlement Area

étiquettes: physical sciences, fossils, permafrost thaw, mammals, biochemical cycling

Objectif(s): To establish the causes of the major changes in sulphur isotopes recorded in fossil bones of mammals at the end of the ice age and to test our working hypothesis that major changes in fossil bone collagen sulphur are linked to changing biogeochemical cycling caused by permafrost thaw.

Description du projet: This licence has been issued for the scientific research application No.5255. The main objective of the project is to establish the causes of the major changes in sulphur isotopes recorded in fossil bones of mammals at the end of the ice age. To achieve this, the research team will test the working hypothesis that major changes in fossil bone collagen sulphur are linked to changing biogeochemical cycling caused by permafrost thaw. Fieldwork will establish the relationship between soil and plant sulphur isotopes and permafrost thaw across a transect of sampling sites spanning continuous and discontinuous landscapes in Northwest Canada. Samples of soil (100-200 g), vegetation (<500 g), water (<200 ml) and ice (<200 ml) will be collected at multiple localities from three regions. In each region soil profiles 1-2m deep and naturally exposed by erosion along the river bank, coastal bluff or in landslides will be cleared of slumped soil by spade and trowel, examined, recorded and sampled. If no natural exposures are available, samples will be collected from digging a small soil pit (0.5 x 0.5 m wide x 0.5-1.0 m deep) or by drilling to 1-2m depth. Pits and boreholes will be carefully infilled afterwards, and the turfer placed. At each specific site, samples will be collected from the active layer and near-surface permafrost at paired sites, one site undergoing thermokarst disturbance, the other site a control (non-thermokarst) site. Human disturbance to the natural sections will be negligible because the sample size and number are small, and any soil cleared from the banks will be quickly eroded away naturally. Fieldwork in the three regions will involve: 1) Inuvik to Tuktoyaktuk Highway (ITH): Four days of fieldwork in August 2022 will be based out of a truck at various locations along the ITH between Inuvik and Tuktoyaktuk; 2) East Channel: Two days of fieldwork in August 2022 will be based out of the Western Arctic Research Center (WARC), Inuvik. A boat and technician operator from WARC will be hired to travel along East Channel to identify several sample sites and transport samples to WARC, and to ensure that wildlife is not disturbed; and 3) Tuktoyaktuk Harbour/coast: Three days of fieldwork will be based out of Tuktoyaktuk. A wildlife monitor from Tuktoyaktuk will ensure that wildlife is not disturbed during fieldwork. The results of the research will be submitted for publication in scientific journals. A summary of the main findings of the research will be published in one or more media outlets in the Northwest Territories. The fieldwork for this study will be conducted from: August 13, 2022 to August 26, 2022