Base de données de recherche des TNO

Régions: Inuvialuit Settlement Region

étiquettes: physical sciences, biology, climate change, permafrost degradation, organic carbon, biogeochemistry

Objectif(s): To collect sediment cores from lakes in the Mackenzie River Delta, and to evaluate their utility as potential archives of information concerning past permafrost stability by assessing down-core changes in the age and supply of terrestrial carbon. Several candidate lakes in the delta will be targeted to maximize the chances of finding the best archives.

Description du projet: Although the widespread permafrost soils in the Arctic rim have the ability to retain terrestrial organic carbon for many millennia, evidence indicates that the recent global warming trend may potentially lead to rapid permafrost destabilization and abrupt release of carbon stored in this vast reservoir. To assess whether this process is underway, and to evaluate its impact on biogeochemical processes, it is important that both the current and past riverine discharge of terrestrial carbon is examined. Specifically, the origin and biological reactivity of this carbon, as well as changes in the timescales of carbon storage on land, must be determined in order to assess the influence of climate change in this region. Sampling is planned for late winter (March/April 2007), when the lakes in the Mackenzie Delta are still frozen. This facilitates coring (through the ice) since no floating platform needs to be transported. It also enables access via ice roads/skidoo (assuming the latter proves more cost-effective or practical than transport by helicopter). Lake sediment cores of different lengths (between 0.5m and 5m) will be obtained using several different methods in order to maximize the chances of success. These will include simple push cores as well as freeze cores and vibracores. All of these coring systems are quite portable. Results of this study will be communicated with local communities through presentations and publications. On-going collaborations between the Woods Hole Research Centre and schools in local Arctic communities via the National Science Foundation-funded ‘Student Partners’ project will provide opportunities for school involvement in sampling different Arctic rivers throughout the year. Fieldwork will be carried out from March 19 to April 13, 2007 in the following areas: Mackenzie Middle Delta lakes (68 deg 43'N, 134 deg 14'W; 68 deg 40'N, 134 deg 42'W; 68 deg 40'N, 134 deg 34'W) and Mackenzie Outer Delta lakes (69 deg 22'N, 135 deg 13'W; 68 deg 18'N, 135 deg 12'W; 69 deg 21'N, 134 deg 50'W; 69 deg 09'N, 135 deg 11'W; 69 deg 09'N, 135 deg 30'W).