Estimating the Influence of Hydrological Connectivity on Carbon Dynamics Across Arctic-Boreal Lakes

Abstract:

Arctic and boreal lakes represent one of the largest natural sources of methane, in part because globally lakes are concentrated in high northern latitudes. However, due to their remote nature, these lakes have been poorly constrained in regional carbon budgets. Considering arctic and boreal lakes are warming at twice the global average rate, one of the significant challenges is to quantify the dynamic response of greenhouse gases due to climate-induced hydrologic changes. In this study, we investigate how hydrologic connectivity drives inorganic carbon dynamics and greenhouse gas fluxes. We present biogeochemical and flux data from 48 northern latitude lakes collected in the summer of 2016 and 2019 across three study sites: (1) The Peace-Athabasca Delta, a freshwater inland river delta in Canada (2) the Yukon Flats Basin in Alaska, and (3) bedrock-controlled Yellowknife-Daring Lake, Canada. We use lake water isotopic values to determine hydrological connectivity and stable isotopes of dissolved inorganic carbon and methane to infer carbon pathways and their sources. Lake carbon dioxide fluxes range from -102 to 604 mmol m^-2d^-1, and methane fluxes range from 0.1 to 4 mmol m^-2d^-1 across the study sites. Preliminary statistical analysis shows strong correlations between hydrologic connectivity and the carbon parameters. These results will provide insight into current conditions in a rapidly changing landscape that will have a significant effect on carbon emissions to the atmosphere.