B13J-06
Tracking Particulate Organic Matter Characteristics in Major Arctic Rivers: Indicators of Watershed-Scale Climate Impacts
Monday, 14 December 2015: 14:55
2006 (Moscone West)
James W McClelland, University of Texas at Austin, Austin, TX, United States, Claire G Griffin, University of Texas Marine Science Institute, Port Aransas, TX, United States, Robert Max Holmes, Woods Hole Research Center, Falmouth, MA, United States, Bruce Jon Peterson, Marine Biological Laboratory, Woods Hole, MA, United States, Peter A Raymond, Yale University, New Haven, CT, United States, Robert G Spencer, Florida State University, Department of Earth, Ocean and Atmospheric Science, Tallahassee, FL, United States, Robert G Striegl, USGS, Boulder, CO, United States and Suzanne E Tank, University of Alberta, Edmonton, AB, Canada
Abstract:
Six large rivers, including the Yukon and Mackenzie in North America and the Yenisey, Ob', Lena, and Kolyma in Eurasia, drain the majority of the watershed area surrounding the Arctic Ocean. Parallel sampling programs were initiated at downstream locations on these rivers in 2003 to improve estimates of fluvial export and track large-scale perturbations associated with climate change. Over a decade later, synthesis of water chemistry data from these ongoing sampling efforts provides an unprecedented opportunity to 1) examine similarities and differences among the major Arctic rivers, and 2) think critically about how changes in various water chemistry parameters may or may not inform us about climate change impacts. River-borne organic matter characteristics may be particularly telling because mass flux values and composition/source indicators vary with hydrology and permafrost coverage. However, separating climate impacts that occur within river corridors from those that occur beyond them may be difficult, especially when considering changes in particulate organic matter (POM) loads. Data on suspended POM yields, C:N ratios, stable isotope ratios, and radiocarbon content in the major Arctic rivers show marked spatial, seasonal, and interannual variability that is helpful for thinking about how climate change effects may manifest in the future, but it will be challenging to separate changes in POM related to bank erosion and suspension/deposition of in situ sediment stocks from changes in POM that may be linked to processes such as permafrost thaw occurring across the broader landscape.
