Spatial and Temporal Variability of the Transformation of Dissolved Matter Runoff in the Mezen River Estuary

Abstract

The spatial and temporal variability of the transformation of dissolved matter runoff in the Mezen River estuary is studied from data on comprehensive hydrological–hydrochemical research in 2009 and 2015. The conservative behavior of major ions and dissolved forms of Li, Rb, Cs, Sr, B, F, As, Sb, and Mo has been revealed. The additional input of phosphates and silicon to solution (to 93% and 32–38% of their content in river water, respectively) is apparently caused by the transport of these nutrients from pore waters, which are regularly muddled by inflow of bottom sediments and vertical mixing of the water column. The desorption flux of barium and uranium due to long-term interaction of terrigenous material with saline water exceeds their input with continental runoff (180–380% and 90–150%, respectively, of their content in river waters). Up to 50, 43, 29, 32, 44, 50, and 45% of Fe, Pb, Y, La, Ce, Pr, and Nd, respectively, supplied by river runoff as stable organic complexes are removed from solution upon entering sea water due coagulation of colloids. It is concluded that transformation regularities of dissolved matter in the Mezen River estuary are spatially homogeneous and temporally stable. The specifics of migration of dissolved phosphates, silicon, barium, and uranium is caused by the hydrological features of the estuary.