Twin Cities Seminar
Dissolved Organic Matter in Major Rivers Across the Pan-Arctic from Satellite Remote Sensing
Arctic rivers represent an important link between terrestrial and coastal carbon cycles, transporting ~35 Tg of dissolved organic carbon (DOC) on an annual basis. In a rapidly warming region, changes in the quantity and quality of dissolved organic matter (DOM) may occur because of thawing permafrost, an accelerated hydrological cycle, and altered microbial processes. Yet, relatively few multi-decadal records of river chemistry exist, particularly for Siberian rivers. Remote sensing of chromophoric dissolved organic matter (CDOM, the portion of the DOM pool that absorbs light), provides an opportunity to investigate DOM in major Arctic rivers over multiple decades. Here, we present the development and application of remote sensing models across six major Arctic rivers. Although CDOM showed no pan-Arctic trends in export, there is evidence of long-term changes in riverine DOM. Discharge-specific CDOM concentrations decreased in the Yenisey River and increased in the Ob’ River. Additionally, CDOM concentrations increased over the past ~30 years within the Mackenzie River. These long-term trends cannot be definitively linked to climate change, but may be related to effects of warming on permafrost, hydrology, and biogeochemistry within Arctic watersheds with consequences for carbon cycling on both regional and global scales.
Dr. Claire G. Griffin’s research links watersheds to dissolved organic matter and nutrients in streams, lakes, and estuaries using a combination of field- and lab-based data, GIS, and remote sensing. In particular, she has worked to understand how organic carbon cycling in Arctic streams and rivers responds to rapid climate change. She received her PhD from the University of Texas Marine Science Institute in 2016, and is currently a postdoctoral associate in Ecology, Evolution, and Behavior at UMN. Her postdoc work relates field, lab, and remotely sensed optical data to watershed characteristics in Midwestern lakes and rivers.