NWT RESEARCH DATABASE

Tags: water quality, aquatic ecosystems, biology, vegetation, metals, aquatic invertebrates

Objective(s): To evaluate the relative sensitivity of northern aquatic invertebrates and northern ecosystems in comparison to southern species and environments. The focus of comparisons is in relation to the toxicity of metals.

Project Description: The objectives of this research are to evaluate the relative sensitivity of northern aquatic invertebrates and northern ecosystems in comparison to southern species and environments. The focus of comparisons is in relation to the toxicity of metals. Three types of sample collections are proposed. These would be done at selected sites along the Ingraham Trail (highway 4) east of Yellowknife. The sites will be chose where there is easy road access to shallow wadeable waters. Water samples of approximately 0.5 L will be collected in pre-cleaned bottles for water quality measurements (e.g. pH, dissolved organic matter, conductivity, hardness, phosphate, sulphate, chloride, turbidity, Cu, and etc.). Collections could be done at 15 to 20 sites in order to identify a subset of locations where more detailed sampling would be done. Samples of aquatic invertebrates will be collected from shoreline vegetation and shallow substrates. The sampling method will be similar to those used for environmental monitoring, standard "kick-and-sweep" using 450 micron D shaped nets. Sampling is expected to be less disruptive than standard environmental monitoring as the area covered will be smaller, a few square meters at most. Biota sampled will be sorted on the shore to identify daphnids and amphipods which will be saved and the other organisms returned to their environment. The saved organisms will be transported to the lab at Laurier for subsequent detailed identification, culture and side by side testing with southern species in order to compare sensitivities to metals. Sites rich in dissolved organic matter (dark, "tea" coloured waters) will be sampled in order to collect and characterize the organic matter. In these collections a small submersible pump, a portable reverse osmosis (RO) system and a small generator are used. Water is drawn from the local source and passed through the RO system where the organic matter is separated from the water. Typically 250 L of water is filtered under pressure to produce 5-10 L of concentrated organic matter. The 240+ L of pure water is unchanged (no additives or chemicals are used) and is returned to the source. The concentrated organic matter will be refrigerated and taken to the lab for detailed characterization. Organic matter has many important functions within aquatic ecosystems and the work on southern environments demonstrates that different sources can have very unique properties. The research team are very interested to compare these with northern organic matter sources. The generator and RO systems limit sampling sites to those accessible by road and often they can stay on the truck. If sites are chosen where it is necessary to bring the generator and equipment onto the ground a plastic tarp will be used under the generator to contain any spills (e.g. when filling the tank with gas). The research team are always keen to discuss the project with anybody who is interested in the goals and/or results. This project is focused on learning about the potential impact metals have to sensitive northern aquatic organisms in their environment. Most of the research activities for this project are lab based studies and characterization but it is focused on the unique nature of northern ecosystems and how these differ from southern Canadian environments. Most of the data generated to derive Canadian Water Quality Guidelines is done in southern waters with southern species and whether (how well) Guidelines are relevant in northern waters is the goal. The research licence is to allow collection of aquatic samples and representative invertebrate organisms (amphipods and daphnia) from NWT sites and these would be then grown in lab conditions and tested alongside southern species. Therefore there are no direct economic benefits but benefits will come from improved confidence in the thresholds for water quality and an understanding of the relative sensitivity of northern organisms and environments. The project results will be communicated under the umbrella of the GNWT/WLU Agreement. Opportunities to present finding at workshop will be developed through the science activities facilitated by the Agreement. Results are also reported annually to Environment Canada as part of their funding agreement and these could be made available to those interested. Publications and graduate theses will be available online via Wilfrid Laurier University. The fieldwork for this study will be conducted from October 18, 2017 to December 31, 2017.