Project Summary
Canadian Beavers commonly build dams and create ponds which alter both the flow, and the chemical properties of water. In mercury-rich areas, the changed conditions may increase delivery of toxic mercury forms to downstream ecosystems. The goal of this research is to determine whether beaver ponds in the Taiga Plains are acting as methylmercury production hotspots, and to determine which water chemistry changes correlate with methylmercury concentration changes between the inflow and the outflow of beaver ponds. I sampled the inflow and outflow of 20 beaver ponds throughout the Taiga Plains in June and August of 2022 to determine whether methylmercury concentrations are being changed by the conditions created by the pond, and what those conditions are. We found no evidence that methylmercury concentration was substantially changed in June. In August, we observed a mean 37.9% reduction in methylmercury concentration, and we are 98% certain that the true change is a decrease. Beaver ponds in the study region act as methylmercury sinks during low-flow periods, with lower methylmercury concentrations in the outflow than the inflow. Longer residence time and higher dissolved oxygen concentration are correlated with greater decreases to methylmercury concentration.
Acknowledgements
I respectfully acknowledge that my on-campus work is located on Treaty 6 land, home and gathering place to many indigenous peoples including Cree, Blackfoot, Métis, Nakota Sioux, Iroquois, Dene, Ojibway/ Saulteaux/Anishinaabe, Inuit, and others, and that my field research is located on Treaty 8 and Treaty 11 territories which are home to Dene, Gwich’in, Tlicho, Sahtu, Cree, Blackfoot, Saulteaux, Nakota Sioux, and Métis peoples. I recognise the land as an act of reconciliation and gratitude to those whose territory this work takes place.
Special thanks to the Dene Tha' First Nation, Łı́ı́dlı̨ı̨ Kų́ę́ first nation, and the Pehdzeh Ki First Nation for their interest and support in this work.
Thank you to Renae Shewan, Kate Marouelli, and Robbie Potts for their help in the field and beyond, as well as my supervisor David Olefeldt and the rest of the CAWS lab for their support.
Special thanks to the Dene Tha' First Nation, Łı́ı́dlı̨ı̨ Kų́ę́ first nation, and the Pehdzeh Ki First Nation for their interest and support in this work.
Thank you to Renae Shewan, Kate Marouelli, and Robbie Potts for their help in the field and beyond, as well as my supervisor David Olefeldt and the rest of the CAWS lab for their support.