Base de données de recherche des TNO

étiquettes: physical sciences, contaminants, water quality, limnology, habitat assessment, paleolimnology, community based monitoring, ecosystem changes

Objectif(s): To coordinate monitoring and research efforts in the watershed between the community, government, and universities; to understand current aquatic health of the watershed using water quality, macroinvertebrates, aquatic furbearers and fish as indicators of ecosystem health; to understand historical environmental change and contaminant loading in the watershed using paleoecological techniques from lake sediment cores; and, to develop a regional community-based water quality monitoring program for the watershed to monitor disturbance and future change in the watershed.

Description du projet: The purpose of this project is to: 1) coordinate monitoring and research efforts in the watershed between the community, government, and universities; 2) understand current aquatic health of the watershed using water quality, macroinvertebrates, aquatic furbearers and fish as indicators of ecosystem health; 3) understand historical environmental change and contaminant loading in the watershed using paleoecological techniques from lake sediment cores; and 4) develop a regional community-based water quality monitoring program for the watershed to monitor disturbance and future change in the watershed. The project can be divided into two major activities: 1) Assessing the current health of the aquatic system in the Tathlina watershed; and 2) Understanding historical environmental change and contaminant loading in Tathlina watershed. Quarterly water quality sampling will occur throughout the watershed (East Cameron, West Cameron, Upper Kakisa River, Middle Kakisa River, and the head of the Lower Kakisa River at the community of Kakisa) as part of a regional water quality monitoring program. Continuous instream water quality loggers will be deployed in several of these streams to track seasonal variability in physical parameters in the watershed. This information will be used by paleoecologists and fish biologists in the project as they strive to understand abiotic conditions in the lake and how these conditions have changed over time. Access to the sample sites will be via snowmobile during winter and by float plane in spring, summer and fall. Samples collected will be analyzed by Taiga Environmental Laboratory in Yellowknife, NT for various physical parameters, nutrients, major ions, hydrocarbons, and 27 trace metals. In order to develop an understanding of the influence of development in the Cameron Hills on the aquatic health of the Tathlina watershed, aquatic sampling of small streams in the Cameron Hills will be completed using Environment Canada's Canadian Aquatic Biomonitoring Network (CABIN) protocol (http://www.ec.gc.ca/rcba-cabin/). A reconnaissance of the area will be conducted to locate appropriate sampling sites. Sites that are downstream from disturbance and sites that are not influenced directly by disturbance will be identified. Approximately 20- 25 sites will be sampled. Both water and benthic macroinvertebrate samples will be collected at each site. Nutrients, major ions, hydrocarbons, total suspended solids and alkalinity will be measured, and invertebrates identified and counted in a lab. Furthermore, on-site water quality measurements (e.g. temperature, dissolved oxygen, turbidity, pH, specific conductance), reach characteristics (e.g. habitat types present, canopy cover, macrophyte coverage, streamside vegetation, periphyton coverage), substrate characteristics and channel measurements (e.g. water velocity, stream width, depth) will also be taken. Water samples will be analyzed and benthic macroinvertebrate samples identified and counted. Data will then be entered into the national CABIN database hosted by Environment Canada with data analysis and interpretation conducted. Researchers from Wilfrid Laurier University will partner with DFO scientists during the winter stock assessment to evaluate fish health in Tathlina Lake. The goal will be to sample 20 males and 20 females of two fish species for body length, body weight, liver weight, gonad weight and ovarian development, and scales or otoliths for aging. Calculation of condition factor (K=W/L3), liver somatic index (liver weight/body weight X 1 00), gonadosomatic index (gonad weight/body weight X 100), size at age, etc. will provide measures of health of fish populations in the lake as per the guidance for the Environmental Effects Monitoring program as mandated through the Fisheries Act for various industries. Reproductive endocrine status will be assessed by measurement of reproductive steroid levels in collected tissue and/or blood samples to assess the potential impact of source water reproductive contaminants. Fuel reserves in the fish will be measured to help researchers better understand the energetic/nutritional status of the fish. Measurements will include determinations of muscle and liver lipid, protein and carbohydrate reserves, which will provide an index of how well fish have been feeding. Fish health measures will be compared to those of other fish populations in similar lakes in the region as funds from other sources permit. Tissue samples will be collected and analyzed for contaminants. Mink is a top trophic level carnivore that readily bioaccumulates environmental pollutants such aspolychlorinated biphenyl (PCBs), dichlorodiphenyltrichloroethane (DDT)-related compounds, and methyl mercury. Mink is a sensitive indicator of ecosystem health as even low levels of PCBs can affect reproduction. A suite of metals including mercury and organochlorine compounds including PCBs will be assessed in mink in this watershed. Samples will be collected by Ka'a gee Tu First Nation (KTFN) trappers as part of their regular harvesting activities and may also be collected as part of community environmental monitoring and on-the-land youth education activities. For each animal, the collection date, location and description of the habitat where collected will be recorded. Carcasses will be frozen until processed at the ENR Fort Smith laboratory, where the sex, weight and body condition indices will be recorded. Stomach content analysis will be conducted for each mink carcass to determine the prey species consumed. Age will be determined from tooth cementum analysis of a lower canine. Stable isotope analyses will be also be conducted to characterize the trophic relationships in the food web. Liver, kidney and fat (inguinal pad) samples will be collected from the mink carcasses. Liver samples will be used for current contaminant analysis, and other samples will be banked for future use. Lake sediment cores will be collected in the western portion of Tathlina Lake and sections will be dated and analyzed for diatoms, chironomids, charcoal and inferred sedimentary chlorophyll a to reconstruct historic climate and abiotic/biotic conditions of Tathlina Lake. Analysis of lake sediments will allow the research team to reconstruct a number of parameters important for this study. Charcoal pieces preserved in the lake sediment will be enumerated to determine the past occurrence of forest fires in this region during the last several centuries and perhaps longer. The occurrence of fire in the lake watershed can have important impacts on lake systems due to increased nutrient and sediment flux. Nutrient fluxes can influence chemical parameters in the lake including dissolved oxygen (DO). Changes in the concentration of DO can have important consequences for fish populations. Using the lake sediment records, the research team will reconstruct the fire history for this region. Chironomids will provide a record of DO levels and the relationship between these two parameters will be examined through the studies. These results will also be analyzed with respect to fish population records that have been assembled during the past several decades to determine the influence of fire on the aquatic system of Tathlina Lake. The remains of diatoms (algae) and sedimentary inferences of chlorophyll a will be used to determine how primary production has changed over time, as well as potentially determine the timing and impact of recent climate change on Tathlina Lake. Sediment cores will be collected in receiving waters downstream of the Cameron Hills oil and gas development area as well as reference headwater lakes in the region to investigate recent and historic contaminant loading to the Tathlina watershed. Sediment cores will be collected in waterbodies of the Cameron River delta and sectioned using well established protocols. Cores will be radiometrically dated by lead-210, radium-226, and cesium-137 activities to establish chronologies of sediment deposition. These dated sediment sections will be analyzed for contaminants, including metals (mercury, cadmium, arsenic, copper, zinc, and others) as well as pyrogenic and petrogenic hydrocarbons (polycyclic hydrocarbons (PAHs) and alkylated PAHs) to assess the effect of upstream oil developments on the Cameron River watershed. The research team will also sample benthic invertebrate populations in these systems and analyze these for the same contaminants listed above to determine whether these contaminants are accumulating in the benthic aquatic food chain leading to humans. This program is being directed by the Ka'a'gee Tu First Nation (KTFN). The concept for the program and the research questions arose from concerns of the KTFN regarding upstream oil and gas development and the cumulative effects of environmental change and multiple resource pressures on the Tathlina Lake area. The project has the full support of Chief and Council. KTFN members will accompany researchers in the field to provide local knowledge on the study area and to ensure safe travel. Opportunities exist for training in environmental data collection and reporting techniques. Some members have already received preliminary training and this project will allow them to practice and enhance their current skill base. A project overview will be presented to the community at a multi-stakeholder gathering to update community members on the project and highlight upcoming activities and opportunities for involvement. A short presentation on the project will be made to local school children to increase awareness of the need for environmental planning. Researchers will meet with band staff whenever in Kakisa to update the community on what they will be doing in the field and to provide recent results. Research team members will report results at relevant northern and nation-wide venues, including regional leadership meetings, northern environmental conferences, the 2012 NWT Geoscience Forum, and other nationwide and international conferences. A plain language summary of the research and conclusions will be prepared for circulation to other Deh cho communities and Deh cho regional leadership. Research results will be disseminated to the wider scientific community through peer reviewed journal publications. As government researchers are partners in this work, the research articles will retain Crown Copyright and can be posted on the CIMP website. A technical report and a plain language summary on the furbearers contaminant monitoring will be written upon completion of the study and analysis. The results will be presented in the community. Results will be provided to the Northwest Territories Regional Contaminants Committee to discuss the significance and communication of the results. The fieldwork for this study will be conducted from January 1, 2013 to March 31, 2013.