Utilizing colored dissolved organic matter to derive dissolved black carbon export by arctic rivers

摘要: Wildfires have produced black carbon (BC) since land plants emerged. Condensed aromatic compounds, a form of BC, accumulated to become major component the soil pool. aromatics leach from soils into rivers, where they are termed dissolved (DBC). The transport DBC by rivers sea is term in global and BC cycles. To estimate Arctic river export, 25 samples collected six largest (Kolyma, Lena, Mackenzie, Ob’, Yenisey Yukon) were analyzed for organic (DOC), colored matter (CDOM), DBC. A simple, linear regression between DOC indicated that accounted 8.9 ± 0.3% exported rivers. improve upon this estimate, an optical proxy was developed based correlation concentrations CDOM light absorption coefficients at 254 nm (a254). Relatively easy measure a254 values determined 410 2004 2010. Each these converted concentration correlation, providing extended record concentration. coupled with daily discharge data riverine loads using LOADEST modeling program. studied cover 53% pan-Arctic watershed 1.5 0.1 million tons per year. Scaling up full area watershed, we carry 2.8 0.3 Ocean each This equates ~8% slightly less than simpler vs correlation-based estimate. Riverine predicted increase warmer Arctic. export positively correlated runoff, suggesting likely as warms.