Dynamics of Dissolved Inorganic Carbon in the Yenisei Gulf during the Open Water Period

Abstract

Based on the materials of several voyages of the Institute of Oceanology, Russian Academy of Sciences, and archival hydrological and hydrochemical data, the dynamics of dissolved inorganic carbon in the Yenisei Gulf was investigated. There are three main areas with extensive sedimentation of suspended material and oxidation of organic matter (OM) in the upper layer of sediments. The first region of OM oxidation was to the south from 72° N; its existence associated with extensive sedimentation of dissolved and suspended matter at the geochemical barrier. Two other areas of OM decomposition were located downstream (between 73° and 74° and to the north from 75° N) and most likely originated at the orographic barrier, where the change in the dynamic characteristics of the riverine flow and the topography of the bay bottom stimulated precipitation of suspension carried by water. Comparison of the difference in the observed Ctot with the AOU value showed that in 1993, oxidation of OM resulted in a change in Ctot. In 2011, carbon emission into water was most likely controlled by the transformation of mineral suspension and/or carbon exchange between bottom water and bottom sediments. In 2016, a decrease in the Ctot content was registered in deep water over the most part of the section. Despite many similar features in the distribution of hydrochemical characteristics in the bay, the change in the content of dissolved inorganic carbon over the section was significant in different years.