title: Insights and issues with simulating terrestrial DOC loading of Arctic river networks.
abstract: Terrestrial carbon dynamics influence the contribution of dissolved organic carbon (DOC) to river networks in addition to hydrology. In this study, we use a biogeochemical process model to simulate the lateral transfer of DOC from land to the Arctic Ocean via riverine transport. We estimate that, over the 20th century, the pan-Arctic watershed has contributed, on average, 32 Tg C/yr of DOC to river networks emptying into the Arctic Ocean with most of the DOC coming from the extensive area of boreal deciduous needle-leaved forests and forested wetlands in Eurasian watersheds. We also estimate that the rate of terrestrial DOC loading has been increasing by 0.037 Tg C/yr2 over the 20th century primarily as a result of climate-induced increases in water yield. These increases have been offset by decreases in terrestrial DOC loading caused by wildfires. Other environmental factors (CO2 fertilization, ozone pollution, atmospheric nitrogen deposition, timber harvest, agriculture) are estimated to have relatively small effects on terrestrial DOC loading to Arctic rivers. The effects of the various environmental factors on terrestrial carbon dynamics have both offset and enhanced concurrent effects on hydrology to influence terrestrial DOC loading and may be changing the relative importance of terrestrial carbon dynamics on this carbon flux. Improvements in simulating terrestrial DOC loading to pan-Arctic rivers in the future will require better information on the production and consumption of DOC within the soil profile, the transfer of DOC from land to headwater streams, the spatial distribution of precipitation and its temporal trends, carbon dynamics of larch-dominated ecosystems in eastern Siberia, and the role of industrial organic effluents on carbon budgets of rivers in western Russia.
authors.affiliation: The Ecosystems Center, Marine Biological Laboratory, Woods Hole, Massachusetts 02543, USA. dkicklighter@mbl.edu
authors.forename: David W
authors.initials: DW
authors.lastname: Kicklighter
authors.affiliation: Institute of Arctic Biology, University of Alaska, Fairbanks, Alaska 99775, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Hayes
authors.affiliation: Marine Science Institute, University of Texas at Austin, Port Aransas, Texas 78373, USA.
authors.forename: James W
authors.initials: JW
authors.lastname: McClelland
authors.affiliation: The Ecosystems Center, Marine Biological Laboratory, Woods Hole, Massachusetts 02543, USA.
authors.forename: Bruce J
authors.initials: BJ
authors.lastname: Peterson
authors.affiliation: U.S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit, University of Alaska, Fairbanks, Alaska 99775, USA.
authors.forename: A David
authors.initials: AD
authors.lastname: McGuire
authors.affiliation: The Ecosystems Center, Marine Biological Laboratory, Woods Hole, Massachusetts 02543, USA.
authors.forename: Jerry M
authors.initials: JM
authors.lastname: Melillo
mesh_terms: D000818:Animals; D001110:Arctic Regions; D002244:Carbon / Q000737:chemistry*; D057231:Climate Change; D003198:Computer Simulation; D017753:Ecosystem; D004784:Environmental Monitoring; D008962:Models, Theoretical; D045483:Rivers / Q000737:chemistry*; D012621:Seasons; D013997:Time Factors
chemical_list: D002244:Carbon