| Summary: | This project seeks to identify mineral weathering reactions and hydrologic processes that control how and at what rate the inorganic solute geochemistry of water evolves during transport within Arctic soils and streams and to establish linkages between chemical weathering phenomena and organic carbon export. Water samples were collected from six watersheds near the Arctic Long Term Ecological Research Station on the North Slope of Alaska. All rivers drain continuous permafrost, but three drain tussock tundra-dominated watersheds (Kuparuk, Imnaviat, and Oksrukuyuk) and three drain bare bedrock catchments with minor tundra influences (Atigun, Roche, and Trevor). Water samples were collected from April until October in 2009 and 2010. Water samples were characterized in the field for pH, temperature, conductivity, and alkalinity (Gran titration). In the laboratory, samples were analyzed for concentrations of cations (Ca, Mg, Na, K, Fe, Sr, and NH4), anions (Br, Cl, F, NO2, NO3, PO4, and SO4), Si, TDN, DOC, DON, POC, PON, and trace metals (Be, B, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Mo, Ag, Cd, Sn, Sb, Te, and Ba). River samples were analyzed for O and H isotope ratios (18O/16O and 2H/1H) to identify water sources. Sulfur isotope ratios (34S/32S) of SO4 were measured to track riverine sulfate sources. C and N isotope ratios (13C/12C and 15N/14N) of POC were measured to track sources of organic carbon in streams. Ca and Sr isotope ratios (44Ca/40Ca and 87Sr/86Sr), combined with C isotope ratios (13C/12C) of DIC, were measured to track solute sources from mineral weathering. Two soil cores were collected from Imnaviat watershed. Cores were sectioned into 5cm intervals and were analyzed by XRF (Sc, Ti, V, Cr, Mn, Ba, Fe, Cu, Zn, Ga, Pb, Br, Rb, Sr, Y, Zr, and Tl). Pore waters from each section were collected and analyzed for trace metals by ICP-MS (B, Al, P, Sc, Ti, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, Ba, and Tl).
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