Genesis of the eastern Barents Sea part water masses using winter data of isotopic parameters δ18O and δ2H

Abstract

The study aims to evaluate the shares of primary waters (Atlantic, river, meltwater, and sea water withdrawn for ice formation) in the resulting water masses in the eastern part of the Barents Sea at the end of the hydrological winter. Moreover, the study compares the outcomes achieved by using salinity-δ¹⁸O and salinity-δ²H values.

The study was based on the data on water temperature and salinity and δ¹⁸O and δ²Н stable isotopes values. We implemented field studies in March and April 2021 at the Dalnie Zelentsy research vessel, providing the only known and available source of data on δ¹⁸O and δ²Н for the eastern part of the Barents Sea between 70⁰ N and 79⁰ N at the end of the hydrological winter. The results allow for estimating the shares of the primary waters, namely Atlantic, river, meltwater, and sea water, withdrawn for ice formation in the sea water during this period of the year in various water masses meltwater. Moreover, they allow for estimating the influence of each of the primary waters on the salinity of the resulting water masses. However, when we calculate the average Atlantic and ice water shares using the δ²H isotopic parameter, they are somewhat higher than those calculated using δ¹⁸O. Conversely, the river water share is somewhat lower.

A 0.36 psμ (0.34–0.51 psμ) change (decrease) in salinity in the Atlantic water mass is due to mixing with river waters and 0.04 psμ (−0.05 to 0.10 psμ) with mixing with meltwater. In the Barents Sea winter water mass these values are 0.63 (0.53–0.71 psμ) and 0.31 (0.27–0.42 psμ), respectively. In the water mass called ‘Surface waters of the Arctic seas, winter’, the processes of ice formation prevail over the processes of ice melting. The average decrease in salinity due to the content of river waters alone could be 0.66 psμ (0.59–0.74 psμ). However, it is only 0.46 psμ (0.41–0.57 psμ) due to salinisation during ice formation.

The quantities of meltwater volumes and volumes of water withdrawn for ice formation serve as specific characteristics of «memory», describing the ice formation/ice melting processes.