Department of Biology, Université Laval
1045 avenue de la Médecine
Roads impact on aquatic ecosystems
Road salt is used on roads in cold regions to remove snow and ice. Road salt is mainly composed of sodium chloride (NaCl), but also contains associated contaminants such as metals, nitrogen and anti-agglutinative compounds. Runoffs then transport these ions and compounds into the environment, particularly to underground and surface water systems. All of these chemicals can be toxic and/or impact the water quality, leading to modifications of the ecosystem. These modifications may be most impactful in spring, when snow and ice melt results in increased transport of water and other materials into the aquatic systems. However, salts remain in lakes almost year through and concentration of chloride has been reported to increase from year to year in some systems.
The objective of my PhD project is to assess the effects of road de-icing salts on lentic ecosystem. More precisely, this project aims to (1) determine the de-icing salt composition, including the associated contaminants, on the studied watersheds; (2) to evaluate increasing salinity impact on plankton community structure (trophic chain) and (3) to determine if salinity leads to the dominance of phytoplankton (especially cyanobacterial) capable of producing toxic bloom.
Several lakes with various characteristics and issues will be studied. The first study lake will be Lac Saint-Augustin, located in the metropolitan region of Quebec City, and that is mostly used for recreational purpose by the residents. Secondly, Lac Saint-Charles will be studied. This lake is located in a more rural region of Quebec City and is a major drinking water reservoir for half of the local population. Finally, some lakes that are minimally altered by humans will be selected in the region of Northern Quebec (Nunavik).
The main study hypothesis is that salinity, contaminants and nutrients favor the dominance of cyanobacteria and other bloom-forming species in watersheds impacted by high concentrations of de-icing salts. It will be tested with a combination of field and laboratory work, including molecular, biochemical and microscopy approaches.