Base de données de recherche des TNO

Régions: Gwich'in Settlement Area, Sahtu Settlement Area, Dehcho Region

étiquettes: physical sciences, climate change, greenhouse gases, carbon fluxes, environmental change, ecological survey, atmospheric pollution

Objectif(s): The objectives of this study are to: assess interannual and seasonal variations and key processes controlling CO2, CH4 and N2O dynamics along the Mackenzie Valley latitudinal gradient; investigate the amount and character of greenhouse gases (GHGs) released; understand physiographic and hydrodynamic conditions that control or influence soil GHGs (distributions and emissions).

Description du projet: The objectives of this study are to: assess interannual and seasonal variations and key processes controlling CO2, CH4 and N2O dynamics along the Mackenzie Valley latitudinal gradient; investigate the amount and character of greenhouse gases (GHGs) released; understand physiographic and hydrodynamic conditions that control or influence soil GHGs (distributions and emissions). The Mackenzie valley region of northwestern Canada has undergone the most warming (1.7 deg C) over the last century in Canada and general circulation models (GCMs) predict that the region will experience increases in mean annual air temperature of up to 5 deg C by end of the century. Since relatively large changes in climate are occurring in this region, this project is designed to improve the understanding of the potential impacts of recent climate change on the total carbon (C) storage, source/sink relationships and greenhouse gas (GHG) emissions of forest and peatland ecosystems of the Mackenzie Valley region. Recent changes in forest and peatland distribution and composition will be assessed across a latitudinal gradient. This study will focus on the point, site and regional scale assessment of C variation in biomass and productivity, C stock estimation, C accumulation rate over the last 50 to 100 years, and the amount and characteristics of GHGs in the Mackenzie Valley. The formation, consumption and thus fluxes of the GHGs (CH4, CO2 and N2O) from forests and peatlands will be determined. Understanding how these GHGs are produced, and in what amounts, will allow the researchers to understand how they may be influenced by both anthropogenic and natural disturbances. The information will be used to develop a model of C storage and dynamics in order to predict future impacts of climate change, and disturbances in northern forest and peatland ecosystems. The researchers will use the following instruments to accomplish the above: 1. Soil gas sample tubes - sampled and analyzed on a seasonal basis for gas concentration (CH4, N2O, CO2) and isotope ratios. The system will also monitor the response of ecosystems (soil moisture, vegetation, chemistry) to changing external conditions such as precipitation, temperature extremes and permafrost control. 2. CH4 eddy correlation flux - Measurements using an Isometric Instruments methane optical spectrometer coupled with sonic anemometry. 3. Flux chamber samples - deployed to determine the net CH4, N2O and CO2 fluxes to compliment the SAS tubes soil profile process and eddy correlation information. For public outreach, the researchers will maintain a web site and produce a booklet which will provide in plain language the effect of climate change and disturbances on vegetation. This study will provide capacity building and training for Northern Scientists and employees of the GNWT including technicians and students. A number of Government of Northwest Territories employees from regional offices will be directly involved in fieldwork to provide northern technical people with an opportunity to maintain and improve their terrestrial ecosystem ecological survey and study skills. Highlights of field and experimental work will be communicated to Northern Communities through the researchers’ collaboration with the GNWT. Additional mechanisms for technology transfer to northern communities (through workshops, conferences, and seminars) will also be used as opportunities as needs arise. GNWT staff involved from regional offices include: Steve Gooderham (Regional Forester, ENR GNWT, Fort Simpson), Paul Rivard (Manager, Forests, ENR GNWT, Norman Wells), Mike Gravel (Manager, Forests, ENR GNWT, Inuvik). Fieldwork will be conducted from July 21 to September 30, 2007 near: - Norman Wells (65 12' 38" 127 00' 53" or 65 15' 06" 127 09' 43") - Inuvik (68 19' 09" 133 32' 02", 68 18' 48" 133 23' 00" or 68 18' 56" 133 26' 02") - Fort Simpson (62 14' 44" 122 34' 23", 62 16' 30" 122 36' 13" or 61 38' 21" 121 24' 23")