Health & Environmental Research Online (HERO)


Print Feedback Export to File
6788165 
Journal Article 
Flux and Seasonality of Dissolved Organic Matter From the Northern Dvina (Severnaya Dvina) River, Russia 
Johnston, SE; Shorina, N; Bulygina, E; Vorobjeva, T; Chupakova, A; Klimov, SI; Kellerman, AM; Guillemette, F; Shiklomanov, A; Podgorski, DC; Spencer, RGM 
2018 
No 
Journal of Geophysical Research: Biogeosciences
ISSN: 2169-8953
EISSN: 2169-8961 
AMER GEOPHYSICAL UNION 
WASHINGTON 
123 
3 
1041-1056 
WOS:000430181200020 
Pan-Arctic riverine dissolved organic carbon (DOC) fluxes represent a major transfer of carbon from land-to-ocean, and past scaling estimates have been predominantly derived from the six major Arctic rivers. However, smaller watersheds are constrained to northern high-latitude regions and, particularly with respect to the Eurasian Arctic, have received little attention. In this study, we evaluated the concentration of DOC and composition of dissolved organic matter (DOM) via optical parameters, biomarkers (lignin phenols), and ultrahigh resolution mass spectrometry in the Northern Dvina River (a midsized high-latitude constrained river). Elevated DOC, lignin concentrations, and aromatic DOM indicators were observed throughout the year in comparison to the major Arctic rivers with seasonality exhibiting a clear spring freshet and also some years a secondary pulse in the autumn concurrent with the onset of freezing. Chromophoric DOM absorbance at a(350) was strongly correlated to DOC and lignin across the hydrograph; however, the relationships did not fit previous models derived from the six major Arctic rivers. Updated DOC and lignin fluxes were derived for the pan-Arctic watershed by scaling from the Northern Dvina resulting in increased DOC and lignin fluxes (50Tgyr(-1) and 216Ggyr(-1), respectively) compared to past estimates. This leads to a reduction in the residence time for terrestrial carbon in the Arctic Ocean (0.5 to 1.8years). These findings suggest that constrained northern high-latitude rivers are underrepresented in models of fluxes based from the six largest Arctic rivers with important ramifications for the export and fate of terrestrial carbon in the Arctic Ocean. 
dissolved organic matter; lignin; seasonality; Arctic river; Arctic Ocean; residence time