Synthesis and Scaling of Hydrologic and Biogeochemical Data on the North Slope and Coastal Zones of Alaska: A Basis for Studying Climate Change

Understanding land-ocean-atmosphere coupling is essential for developing an integrated view of the arctic system, and is a key component of the Study of the Northern Alaska Coastal System (SNACS) program. As an important contribution to SNACS, this is an investigation of the linkage between hydrologic variables and constituent (nutrients and organic matter) fluxes from the North Slope of Alaska to the Alaskan Beaufort Sea. The overarching goal of the work is to develop a generalized understanding of discharge-constituent relationships in arctic basins. The primary question is: What are the relationships between discharge and constituent concentrations in the three largest North Slope basins (Kuparuk, Colville, and Sagavanirktok) and have these relationships changed over the past 25 years of rapid warming in the Arctic? Three sub-questions that emphasize specific spatial and temporal components of the primary question are: 1) What are the contemporary fluxes of C, N and P from the three largest North Slope basins to the Alaskan Beaufort Sea. 2) How do discharge- constituent relationships differ among the 3 largest North Slope basins? 3) How do the discharge-constituent relationships over the past 25 years inform us about future changes?

To address these questions, the group take advantage of extensive data collected in the Kuparuk River as a core part of the Arctic LTER project. Researchers have been actively involved in gathering nutrient and organic matter data and recording discharge in the Kuparuk River since the late 1970s. The team will use these data to define discharge-constituent relationships over the open-water season. They will develop transfer functions for use with an existing hydrologic model (the NASA Catchment-based Land Surface Model, CLSM) to estimate contemporary and long-term constituent fluxes from the Colville and Sagavanirktok river basins. This approach is necessary because we lack sufficient historical data on the Colville and Sagavanirktok for a direct analysis. Estimates of contemporary fluxes will be compared to measurements made on the Sagavanirktok and Colville rivers during Year 2 and Year 3 of the project.

The generalized discharge-constituent transport relationships that will be defined are needed to synthesize information now being collected at many locations and at many scales. For example, at the Arctic LTER site a current BioComplexity project is modeling hillslope and small catchment hydrology and biogeochemistry. The LTER streams group is studying nutrient spiraling at the scale of the entire Kuparuk catchment. At a much larger scale, work supported by the Freshwater Initiative is quantifying contemporary land-ocean fluxes from the Ob, Yenisey, Lena, and Kolyma rivers in Russia, and Mackenzie and Yukon rivers in North America.

Education and Outreach will be emphasized throughout the project. In addition to graduate student participation, the group intends for REU students (Research Experience as Undergraduate) to participate in Years 2 and 3 of the project, both in the field and in the lab.