Sources of fresh water components in seawaters of Western part of the Bering Sea according to isotope (δ¹⁸О, δD) data

The estimates of isotope parameters and sources of fresh water components for subsurface, intermediate, and deep waters of Western part of the Bering Sea were carried out using the isotope (δ18О, δD) data for 177 seawater samples. We show that subsurface, dichothermal and, partially, intermediate waters ( 1000 м) are freshened by the regional atmospheric precipitations. For these waters the next equations of relations between delta values and salinity were obtained: δ18О = [0.39 ± 0.02]S – 13.52 ± 0.61 and δD = [3.1 ± 0.1]S – 107.0 ± 2.7. A deeper (1000–2500 m) waters also freshened by atmospheric precipitations, but from the more south region (≈ 40–45 S). The deepest waters (2800–4300 m) are preserving their isotope signal obtained by freshening with meltwaters of Antarctic glacier ice. The distribution of isotope parameters with the depth shows that the vertical mixing at the ≈1000–2500 m depth take place. This process should influent on the re-distribution of the biogenic elements, dissolved oxygen, organic matter, and other components in waters of the Western part of the Bering Sea. Isotope composition of waters passing into the Arctic Ocean halocline (S = 33.1) from the Bering Sea are δ18О = –0.61‰, and δD = –5.4‰.