Alexander, C.R. and Windom, H.L., 2017. Material mobilization and transport in the Anadyr River-Estuarine system, eastern Siberia.
Water and sediments samples collected from the Anadyr River, one of the most pristine Siberian watersheds, and its associated estuarine and coastal region were analyzed for a variety of inorganic constituents, trace metals, and stable and radioisotopes to assess the mobilization and fate of materials transported along this fluvial–marine pathway. Sampling campaigns occurred during high and waning river discharge: the former concentrated primarily on the fluvial part of the system and the latter, the estuarine and coastal areas. A major focus of this report is on trace metal geochemistry, but results also address sediment provenance, transport, and deposition. The fluvial concentrations of most of the trace metals analyzed (i.e. Fe, Mn, Co, Cu, Ni) are elevated in thermokarsted areas along the river course because of groundwater inputs to surface waters, presumably resulting from seasonal thawing of permafrost. Further down, river concentrations decrease, most likely because of removal to particles. The estuarine distribution of dissolved trace metals indicates that there is little biogeochemical alteration during their transport through the estuarine/coastal region. Estuarine concentrations of Cu, Ni, Zn, Cd, U, and Fe are generally conservative with respect to salinity. The estuarine concentrations of the other trace elements studied (Mn, Co, Mo, and V) show no distinct pattern relative to salinity. 210Pb and 137Cs activities and trace metal, organic carbon and nitrogen concentrations, and δ13C in surface and down-core sediments indicate that the Onemen Bay-Anadyr Bay estuarine system effectively traps particles originating from the watershed and from the Bering Sea. Onemen Bay is dominated by fluvial sources, whereas Anadyr Bay appears to be dominated by particles of a more oceanic provenance.