Doctoral Dissertation Research: The impact of permafrost thaw on the fate and magnitude of carbon aquatic transport from Arctic tundra soil

Northern Arizona University, Flagstaff AZ

Investigators

Abstract

Permafrost thaw in Arctic watersheds triggers the release of previously sequestered, ancient carbon to the atmosphere and to stream systems - a feedback that accelerates climate warming. Atmospheric release of carbon has been well-documented for decades; however, water is more difficult to monitor and its role in the Arctic carbon cycle has often been overlooked. This research will explore the environmental drivers that Arctic groundwater and headwater streams play in long-term permafrost carbon release. Better understanding the emerging role that water plays in the carbon cycle in a warming Arctic will help improve regional carbon budgets, quantifying the amount of carbon lost from the land that is exported via rivers in a watershed underlain by permafrost. The research will also aid in monitoring the impacts that climate change and resulting permafrost thaw have on ancient permafrost carbon release by carbon dating the dissolved carbon carried away in rivers to identify ancient permafrost signatures. At a long-term experimental study site in interior Alaska, 50% of the soil carbon lost from soils annually was unaccounted for in atmospheric carbon flux measurements. The missing 50% of carbon lost is hypothesized to be exported in dissolved organic carbon fluxes and that an increasing amount of ancient, permafrost carbon is released each year with increasing permafrost thaw. This research will (1) help to resolve the Arctic net ecosystem carbon budget and help to parameterize future Earth System Models; (2) identify the proportion of dissolved organic carbon that is ancient permafrost carbon, using radiocarbon dating; and (3) identify how environmental drivers, such as thaw, impact dissolved organic carbon concentration and age in order to help constrain future predictions of dissolved organic carbon export. Further, the project team will facilitate various outreach activities in Arizona and within the local community surrounding the field site in interior Alaska, to include the broader public as well as a future cohort of young scientists in this work. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.