RII Track-4: Modeling Dissolved Organic Matter at the Arctic land/ocean interface.

University Of Alaska Fairbanks Campus, Fairbanks AK

Investigators

Abstract

Non-technical Description Mathematical models that describe the Arctic Ocean ecosystem can act as early warning predictors for a changing climate, and enhance understanding of how changes in the Arctic region influence the global carbon budget. Scientists track carbon on global, regional and local scales through annual carbon budgets which include both sources (income) and sinks (loss or expenditure). Organic carbon from watershed-draining rivers in the northern permafrost region is a critical component of the Arctic carbon budget. However, this carbon source is poorly represented in existing Arctic Ocean models. In the context of thawing permafrost, changes to the dissolved carbon supply in these Arctic rivers may influence ocean chemistry, as well as the availability of light and nutrients to plants in the Arctic marine environment. This fellowship will allow the PI and a graduate student to establish a research collaboration with the Computational Physics and Methods Group at the Los Alamos National Laboratory (LANL) in New Mexico to develop improved models of the dynamics of dissolved organic matter from rivers in Arctic Ocean and Earth system models. In addition, it will enable the PI to extend from shelf/basin ocean dynamics to ecosystem research focused on the land/ocean interface. This research will enable a better assessment of the impacts of a changing climate on the import and export of carbon in Arctic coastal regions. These improved models will be valuable resources for national and international investigators studying both the Arctic and global carbon dynamics. In addition to establishing the collaboration, the fellowship will enhance student training. The new research skills and collaborative partnerships with LANL personnel will enhance the PI?s career trajectory, strengthen collaboration between the University of Alaska Fairbanks (UAF) and LANL, and build on UAF?s reputation as a center of excellence in Arctic research. Technical Description The fluvial input of dissolved organic carbon plays an important role in carbon cycling on Arctic shelves; however, it is poorly represented in current Arctic Ocean models. This project will develop improved representation of biogeochemical processes associated with riverine dissolved organic matter inputs to better assess the potential impacts of climate change to the biological pump and the sequestration of carbon in Arctic coastal regions. Existing observations of carbon in Arctic rivers will be used to develop model drivers corresponding to major Arctic rivers for incorporation into the global Earth system model developed by the High-Latitude Application and Testing of Global and Regional Climate Models team, based at LANL. This project will also yield an improved representation of dissolved organic carbon compounds within the biogeochemical component of LANL?s high latitude (HiLAT) model. Model simulations will help researchers assess whether and how the strength of primary production and. The updated model will be used to help researches determine the impact of riverine DOM concentration on the strength of the biological pump in the Arctic coastal regions. Specifically, the variability in annual primary production, and the annual export of carbon to the benthos, over each Arctic shelf will be quantified for present and likely future riverine DOM input. Annual carbon budgets will be computed and used to determine likely future changes to the net flux of carbon on Arctic shelves, and thus the global carbon budget.