Sources and Mechanisms of Seawater Freshening in Tsivolky and Sedov Bays (Novaya Zemlya Archipelago) Based on Isotope Data (δD and δ18О)

Abstract

Three-year monitoring (2014–2016) of isotope parameters (δD and δ18О) of water in Sedov and Tsivolky bays (Novaya Zemlya Archipelago) freshened by water of different origin (continental river runoff, atmospheric precipitation, and water supplied from the archipelago) showed that the degrees of freshening and sources of fresh water components were different for water located at different depths. The variability of the δD and δ18О values was characteristic only of surface layer water containing up to 30% freshwater component. In 2015, surface water of Sedov Bay contained Ob River water, whereas water supplied from Novaya Zemlya predominated in Tsivolky Bay. The deep water of both bays showed evidence of freshening by high-latitude atmospheric precipitation. This water might have been transported via the St. Anna and Voronin troughs. The difference in freshening mechanisms of water in Sedov and Tsivolky bays was determined by the different seafloor morphologies and degrees of free exchange with Kara Sea water.