Grant: Canada Research Chairs

Carbon stores in boreal and sub-arctic landscapes are critical to global climate but under threat from rapid climate change, yet these vulnerable stores are simultaneously cited as part of nature-based climate solutions. Decades of research tells us that ecosystem response to climate change involves region-specific drivers and interactions among multiple climate change factors. Thus place-based knowledge and process understanding at this scale is needed to inform Earth System Models (ESMs) and our predictive understanding of ecosystems including their carbon accumulation and storage. In boreal and sub-arctic regions, a large share of atmospheric carbon taken up by terrestrial ecosystems is mobilized as dissolved organic carbon (DOC) through hydrologic pathways as part of the terrestrial to aquatic (T-A) carbon flux. This research program focuses on the transformation and fate of DOC across the terrestrial-aquatic and river-marine interface to improve our understanding of (1) climate change impacts on terrestrial DOC fate within boreal forests and the downstream aquatic environment, (2) the role of the T-A flux in assessing and predicting the carbon balance of boreal landscapes in a future warmer climate, and (3) controls on terrestrial DOC fate in high latitude coastal ecosystems. Research coupling the use of archived samples, infrastructure, and experimental workflows from the latitudinal transect and experimental watershed sites established in the original CRC program, and community-developed, based and supported monitoring will address the following questions: 1. Do climate change impacts on DOC mobilization result in changes to its composition that further influences its fate in soil or the aquatic environment? 2. Does inclusion of the T-A flux of DOC improve our ability to assess and predict boreal landscape carbon balance in a warming world? 3. How may river inputs, and their controls on terrestrial DOC fate, vary across watersheds of the Northwest Atlantic boreal-subarctic coastal margin? This research spanning soil pedon, watershed, and regional scales will provide insights informing fundamental controls on boreal carbon stores and fate of terrestrial DOC in the aquatic and marine environment. Knowledge gained through this research will provide direction for ESM development, direct inputs for the national carbon budget model, and local and regional ecosystem understanding and capacity relevant to resource management and climate adaptation.