Distribution of Optical and Hydrological Characteristics in the Antarctic Sound Based on the Measurements in January, 2022 in the 87th cruise of the R/V Akademik Mstislav Keldysh

Purpose. The purpose of the work is to study the different-scale features of distribution of the hydrooptical and hydrological characteristics in the Antarctic Sound based on the contact and satellite measurements carried out in January, 2022 in the 87th cruise of the R/V Akademik Mstislav Keldysh. Methods and Results. The data of complex natural measurements performed at the oceanographic stations in the Antarctic Sound on January 27-28, 2022 in the 87th cruise of the R/V Akademik Mstislav Keldysh were used. Additionally, the satellite data were analyzed. Complex hydrophysical equipment permitted to obtain the vertical profiles of temperature, salinity, dissolved oxygen, chlorophyll a concentration, fluorescence intensity of colored dissolved organic matter, intensity of the beam attenuation coefficient at 660 nm and photosynthetically active radiation. Based on these data, the main features of mesoscale circulation within the cyclonic gyre over the deep-sea part in the southern Antarctic Sound were determined. The joint analysis of hydrooptical and hydrological characteristics, and satellite measurements in the Antarctic Sound obtained in course of the Antarctic expedition showed presence of a system of the alternating anticyclonic and cyclonic eddies in the area under study. It is also shown that in the ice drift area polluted by land soils or shelf bottom sediments, a zone of the increased turbidity arises that is related to the terrigenous suspension entering into the water during ice melting. Conclusions. The system of the different-scales eddies and currents in the Antarctic Sound contributes to the water exchange between the upper and deep layers of the strait, as well as between the Weddell Sea water spreading to the north-northwest along the slope of the strait basin adjacent to the shelf edge of the Antarctic Peninsula and the Bransfield Straight waters spreading along the slope of the islands' shelf which is the northeastern boundary of the strait.

Automated summary

The purpose of this study is to investigate the distribution characteristics of hydrooptical and hydrological features in the Antarctic Sound at different scales based on contact and satellite measurements conducted in the 87th cruise of the R/V Akademik Mstislav Keldysh in January 2022. The analysis of oceanographic station data and satellite data revealed the main features of mesoscale circulation within the cyclonic gyre and the presence of alternating anticyclonic and cyclonic eddies in the Antarctic Sound. In addition, a zone of increased turbidity was detected in the ice drift area, which was attributed to terrigenous suspension entering the water during ice melting. The different-scale eddies and currents in the Antarctic Sound contribute to water exchange between upper and deep layers and between Weddell Sea water and Bransfield Straight waters.