Abstract
Climate change is a major driver of permafrost thaw and wildfires in peatlands, causing a myriad of issues for northern communities. This project aims to improve our knowledge of water quality in the understudied, peatland-rich Dehcho Region (DR) and Hay River watershed (HRW) in the Northwest Territories and Alberta, with a focus on understanding the mobilization of dissolved organic carbon (DOC) and the easily bound/co-transported neurotoxin methylmercury (MeHg). MeHg is important as it bioaccumulates in fish, which is a key food for local communities, and this bioaccumulation poses a risk to northern communities. This is pertinent to the HRW and DR since peatlands cover >30% of the area and are likely the primary source of these solutes, given the biogeochemistry of anoxic waterlogged soils, and their close hydrological connectivity. This project was co-developed with the Dene Tha’, K'atl'odeeche, and Łı́ı́dlı̨ı̨ Kų́ę́ First Nations due to concern regarding MeHg contamination in fish and drinking water. Four streams were sampled eight times from April - October 2023, as well as equipped with in situ water chemistry sensors. The first objective of this study is to determine whether seasonality has an impact on methylmercury export in northern streams. This study was unable to come to conclusions on the impacts of weather events due to an extreme drought and wildfires. However, the study was able to determine that since snow melt instead was a period of higher hydrological connectivity, MeHg concentrations were higher than during low periods of hydrological connectivity. Turbidity acted as the key influencing variable in water chemistry difference between streams during snow melt, where as electrical conductivity was the influencing variable during the summer. The second objective was to determine the value of in situ sensors to act as a proxy for MeHg by using Fluorescent Dissolved Organic Matter (fDOM) sensors, as no equivalent exists for MeHg. This study found that fDOM sensors are an effective tool for high frequency, in situ monitoring of DOM and MeHg. However, further validation of the fDOM sensor values is needed, particularly during summer storm events, to properly understand the temporal impacts on MeHg export in northern streams, as previous studies have found summer storms to be of particular importance.
About Me
Fares Mandour is enrolled in an MSc in Water and Land Resources in the Department of Renewable Resources at the University of Alberta. He is studying how seasonality, hysteresis, and wildfires can impact methylmercury and dissolved organic matter export in peatland catchments of varying permafrost extent in the Dehcho and Hay River watersheds. His research is part of a longer-term water monitoring project within the Catchment and Wetland Science Research Group at the University of Alberta, where the group studies the impacts of climate change, disturbances, and land management practices on catchment and wetland functions. |
Figure 1. Fares sampling for dissolved organic carbon at Escarpment Creek, NWT in June 2023.
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Acknowledgements
I respectfully acknowledge that where I work, the University of Alberta, is located on Treaty 6 Territory, a traditional gathering place for diverse Indigenous peoples including the Cree, Blackfoot, Métis, Nakota Sioux, Iroquois, Dene, Ojibway/ Saulteaux/Anishinaabe, Inuit, and many others whose histories, languages, and cultures continue to influence our vibrant community. Additionally, my field research is conducted on Treaty 8 and Treaty 11 Territories, which is home to the Dene, Gwich’in, Tlicho, Sahtu, Cree, Blackfoot, Saulteaux, Nakota Sioux, and Métis peoples. I recognize the privilege that I have to be able to travel to and work in these lands, and express extreme gratitude for this privilege.
A special thanks to the Dene Tha’, K'atl'odeeche, and Łı́ı́dlı̨ı̨ Kų́ę́ First Nations, who were key partners in developing the goals for this project and advocating for this research to be done.
Thank you to Jazmin Greyeyes-Howell, Kasha Kempton, Jessica Lagroix, Matthew Munson, and Renae Shewan for their help with sampling this past summer, and for their help with getting settled into the lab! As well, thank you to my supervisor, Dr. David Olefeldt for his continuous support.
Thank you to the funders of this project: the Government of Alberta and the Government of Northwest Territories through the Transboundary Water Agreement.
A special thanks to the Dene Tha’, K'atl'odeeche, and Łı́ı́dlı̨ı̨ Kų́ę́ First Nations, who were key partners in developing the goals for this project and advocating for this research to be done.
Thank you to Jazmin Greyeyes-Howell, Kasha Kempton, Jessica Lagroix, Matthew Munson, and Renae Shewan for their help with sampling this past summer, and for their help with getting settled into the lab! As well, thank you to my supervisor, Dr. David Olefeldt for his continuous support.
Thank you to the funders of this project: the Government of Alberta and the Government of Northwest Territories through the Transboundary Water Agreement.