Examining relations among hydrology, carbon, and important catchment characteristics in lakes and rivers of Old Crow Flats, Yukon

• Main Author: Pearce, Michelle
• Other Authors: Department of Earth Sciences
• Format: Thesis
• Language: English
• Published: Brock University 2023
• Subjects: carbon concentrations; thermokarst lakes; permafrost; water isotope tracers; stable carbon isotopes; Yukon; Old Crow Flats; Gwitchin; Ice; Old Crow; Thermokarst
• Online Access: http://hdl.handle.net/10464/17805

Northern ice- and lake-rich permafrost regions are experiencing changing climate conditions, such as increased precipitation, that have led to various landscape changes (e.g., enhanced hydrological connectivity, catastrophic lake drainage, increased shrub vegetation). These landscape disturbances may alter the biogeochemical cycling of lakes and rivers, especially carbon cycling. Many uncertainties remain regarding how further climate-driven landscape changes will influence the mobilization and cycling of carbon to downstream environments. Old Crow Flats (OCF), Yukon, is a 14,500-km2 watershed with over 8700 thermokarst lakes and ponds that is the traditional territory of the Vuntut Gwitchin First Nation. Both the Vuntut Gwitchin First Nation and researchers have observed landscape changes leading to concerns about how these changes will impact the lake ecosystems and downstream environments. Analysis of dissolved organic and inorganic carbon concentrations and stable carbon isotopes of the 14 long-term monitoring lakes and 25 river sampling locations showed spatial variability in the concentrations and potential sources of carbon in OCF based on lake catchment characteristics and hydrological connectivity. Results presented here act as a baseline of how dissolved carbon concentrations in the lakes and rivers have responded to changing climate conditions over the past decade and identify the potential sources of carbon in the Old Crow Flats drainage network. This research highlights the complexity of carbon cycling and the need to maintain long-term monitoring of relations between climate, landscape characteristics, and surface water across sensitive permafrost regions.