NWT RESEARCH DATABASE

Tags: water quality, aquatic ecosystems, biology, benthic invertebrates

Objective(s): To establish the importance of lake connectivity in determining the community composition and species richness of the invertebrate community of a lake, and the contribution of lakes of differing connectivity to the regional diversity of the Mackenzie Delta; to characterize the response of invertebrate communities to changing peak flood levels to allow prediction and monitoring of future changes, and, to examine historical patterns of community variability due to changing inputs of water and organic material.

Project Description: The objectives of our study are to 1) establish the importance of lake connectivity in determining the community composition and species richness of the invertebrate community of a lake, and the contribution of lakes of differing connectivity to the regional diversity of the Mackenzie Delta, 2) characterize the response of invertebrate communities to changing peak flood levels to allow prediction and monitoring of future changes, and 3) examine historical patterns of community variability due to changing inputs of water and organic material. Field methods for the study involve the collection of water and sediment samples. Lakes located along the channels in the Mackenzie Delta will be accessed by boat, and lakes in the uplands near Reindeer Station will be accessed by helicopter. The research team will be using a multi-parameter probe (YSI) to measure depth, water temperature, pH, conductivity and dissolved oxygen. Water samples (2L) will be collected using pre-cleaned plastic bottles, by collecting samples from just below the water surface. Three replicate benthic invertebrate samples will be taken using a 500-um kick-net over a 1 square metre area for each sample. Material and invertebrate organisms at the bottom of the lake will be suspended by kicking the sediment and sweeping the net through the suspended material for a 3-minute sampling period. To assess long-term changes in the benthic communities, the research team will collect 2 sediment cores and water samples from the center of each lake, which will be accessed by helicopter. These samples will be brought back to the Aurora Research Institute (ARI) for preservation in ethanol and then shipped to York University in Toronto for processing. In the summer of 2016, R. Scott gave a presentation on his PhD research to ARI and community members as part of the summer speaker series, and could do so again this year. The team will provide posters and other written information on the research to ARI, and are always willing to give talks to the community on the research and activities, if the research team are invited. This study will result in a PhD thesis (by R. Scott) which will be provided to ARI after completion, and in several research paper manuscripts intended for journal publication. Preliminary results have been and will continue to be presented at relevant academic conferences (e.g. Society of Canadian Limnologists, ArcticNet). Members of the field team are also always willing to present to local community groups or at ARI while in the north. The fieldwork for this study will be conducted from July 25, 2017 to August 11, 2017.