NWT RESEARCH DATABASE

Regions: Inuvialuit Settlement Region, Gwich'in Settlement Area

Tags: water quality, permafrost, aquatic ecosystems, zooplankton, climate change, soil chemistry

Objective(s): To evaluate the potential impacts of permafrost thaw on water quality and zooplankton communities in Gwich'in lakes; and to determine if differences in soil composition might influence the response of zooplankton communities to the impacts of melting permafrost.

Project Description: Zooplankton play a key role in aquatic food webs, providing a conduit for the movement of energy between primary producers (algae) and larger organisms such as macroinvertebrates and fish. Therefore, elucidating the impact of permafrost melting on zooplankton is key to gaining a broader understanding of climate change on aquatic ecosystems in Canada’s north. Objectives of this proposed research are to: 1) evaluate the potential impacts of permafrost thaw on water quality and zooplankton communities in Gwich'in lakes; 2) determine the factors that control the distribution and abundance of zooplankton communities in the Northwest Territories; and, 3) determine if differences in soil composition might influence the response of zooplankton communities to the impacts of melting permafrost. In collaboration with permafrost scientist from the Northwest Territories Geological Survey, the team will collect zooplankton, aquatic environmental data (e.g., pH, temperature), and shoreline soil samples, from 50 lakes found along the Dempster Highway between Fort McPherson and Inuvik, NT. To collect water and zooplankton samples, the research team will take a small inflatable boat out onto each lake, collect a small water sample (about 2 liters), and pull a small mesh zooplankton net (30cm diameter) through the water. Shoreline soil samples will be collected using a soil core sampler which will dig out a small cylindrical sample of soil weighing less than 1kg. In the laboratory, soil samples will be analyzed for organic matter content, inorganic nutrients, and major ions. This information will allow the research team to examine differences in leachate composition as permafrost melts in areas with differing soil types. Zooplankton collected from the 50 survey lakes will be identified to the species level, and redundancy analysis and spatial modeling will be used to determine the main variables structuring zooplankton communities in the region. Redundancy analysis can be viewed as an extension of multiple linear regression, but instead of using only one response variable, the abundance of each zooplankton species in the community is a response variable. The spatial modeling aspect of this analysis will allow us to determine if zooplankton communities exhibit spatial structure across the landscape that might indicate low dispersal levels (i.e. individuals can’t easily move among lakes). In the case of low dispersal levels, local water quality variables, such as pH, may only partially contribute to explaining differences in zooplankton communities among lakes. Put more simply, redundancy analysis and spatial modeling will allow the team to determine which variables (e.g. water pH, lake depth, dispersal) determine the composition and relative abundance of zooplankton species in NT lakes. If variables such as conductivity are important, then this would indicate that permafrost melting could cause significant shifts in zooplankton communities. In contrast, if a gradient of conductivity exists among our survey lakes, but conductivity values fail to explain differences in zooplankton communities among lakes, then the research team wouldn’t expect permafrost melting to lead to large changes in zooplankton communities. This project will provide an opportunity for students in the Environment and Natural Resources (ENR) program at Aurora College to gain fieldwork experience working in aquatic ecology. The students will have an opportunity to learn about research being conducted in the NWT and will be trained in standard water quality and biological sampling of lakes. This project will examine how climate change will impact aquatic habitats in the NWT. The results of the research will be disseminated to the Government of the Northwest Territories (GNWT), the Gwich’in Tribal Council, as well as the general public. It is the hope that governments will use this data as they develop management plans and consider adaptation efforts in response to climate change. The results of this research will be presented at regional (Pan-Territorial) and national meetings. The research team will publish the results in refereed scientific journals and will seek to gain media coverage for that work by working with the Laurier Communications and Public Affairs Office. The Laurier-GNWT has a staff member responsible for communicating research findings to senior government officials so that relevant information might be considered when developing environmental policies. The research team will also reach out to the Gwich’in Tribal Council and local Renewable Resource Councils and ask for opportunities to explain the project, receive input from local community members, and eventually communicate the results of the study. At the conclusion of the study, the research team will submit a Northwest Territories Environmental Research Bulletin that will aim to communicate the results to community members in plain language. The fieldwork for this study will be conducted from August 19, 2017 to September 7, 2017.