Note: Intro -- Acknowledgments -- Introduction -- Contents -- Part I: Atmosphere-Ocean Interaction and Physical Oceanography -- Chapter 1: Geostrophic and Wind-Driven Components of the Antarctic Circumpolar Current -- 1.1 Introduction -- 1.2 Description of the INMOM Ocean Global Circulation Model and Scenarios of Experiments -- 1.3 Geostrophic and Wind-Driven Parts of the Antarctic Circumpolar Current -- 1.4 Discussion -- 1.5 Conclusions -- References -- Chapter 2: Multi-jet Structure of the Antarctic Circumpolar Current -- References -- Chapter 3: Frontal Zone Between Relatively Warm and Cold Waters in the Northern Weddell Sea -- 3.1 Introduction -- 3.2 Data -- 3.3 Results -- 3.4 Hydrology of the Region -- 3.5 Hydrochemistry -- 3.6 Optical Properties -- 3.7 Phytoplankton -- 3.8 Zooplankton -- 3.9 Conclusions -- References -- Chapter 4: Water Masses, Currents, and Phytoplankton in the Bransfield Strait in January 2020 -- 4.1 Introduction -- 4.2 Data -- 4.3 Temperature, Salinity, and Currents -- 4.4 Hydrochemical Structure of Waters -- 4.5 Pelagic Microalgae Communities -- 4.6 Conclusions -- References -- Chapter 5: Intra-annual Variability of Water Structure in the Atlantic Sector of the Southern Ocean Based on the ECMWF ORA-S3 and OI SST Reanalysis -- 5.1 Introduction -- 5.2 Data and Methods -- 5.3 Results -- 5.4 Conclusions -- References -- Chapter 6: The Circulation and Mixing Zone in the Antarctic Sound in February 2020 -- 6.1 Introduction -- 6.1.1 Study Site -- 6.1.2 Materials and Methods -- 6.1.2.1 Satellite Images -- Synthetic Aperture Radar Images -- Optical Imaging of the Ocean Surface -- 6.1.2.2 Ship Measurements -- 6.2 Results -- 6.2.1 Satellite Observations -- 6.2.2 CTD Results -- 6.2.3 Results of Measurements of Currents Using SADCP -- 6.3 Discussion -- 6.4 Conclusions -- References. , Chapter 7: Rogue Waves in the Drake Passage: Unpredictable Hazard -- 7.1 Introduction -- 7.2 Field Data of Anomalously Large Waves in the Drake Passage -- 7.3 Wave-Current Interaction as a Mechanism of Rogue Wave Formation -- 7.3.1 Unidirectional Wave Propagation -- 7.3.2 Wave Refraction on a Shear Flow -- 7.4 Anomalously Large Internal Waves -- 7.5 Conclusions -- References -- Chapter 8: Water Mass Transformation in the Powell Basin -- 8.1 Introduction -- 8.2 Regional Oceanography -- 8.3 Data and Layer Definitions -- 8.4 Preliminary Results -- 8.4.1 Mixing and Transformation of WDW and WW -- 8.4.2 Weddell Sea Slope Water and Hydrological Role of Its Inflow into the Powell Basin -- 8.5 Conclusions -- References -- Chapter 9: Interannual Variations of Water Mass Properties in the Central Basin of the Bransfield Strait -- 9.1 Introduction -- 9.2 Data and Methods -- 9.3 Density Loss of Bransfield Deep Water in the Central Basin of the Bransfield Strait -- 9.4 Discussion -- 9.5 Conclusions -- References -- Chapter 10: Sea Surface Temperature and Ice Concentration Analysis Based on the NOAA Long-Term Satellite and Sea-Truth Data in the Atlantic Antarctic -- 10.1 Introduction -- 10.2 Initial Data -- 10.3 Data Analysis of Sea Ice Concentration -- 10.4 Data Analysis of Sea Surface Temperatures -- 10.5 Conclusions -- References -- Part II: Chemical Oceanography, Seawater Optical Properties, Productivity and Microbial Processes -- Chapter 11: Hydrochemical Structure of Waters in the Northern Weddell Sea in Austral Summer 2020 -- 11.1 Introduction -- 11.2 Materials and Methods -- 11.3 Results -- 11.4 Discussion -- 11.5 Conclusions -- References -- Chapter 12: Features and Processes of the Oxygen and pCO2 Dynamics in the Surface Waters in the Western Parts of the Weddell and Scotia Seas (Southern Ocean) -- 12.1 Introduction -- 12.2 Materials and Methods. , 12.3 Results -- 12.3.1 The Oxygen Distribution -- 12.3.2 pCO2 Dynamics -- 12.4 Discussion -- 12.5 Conclusions -- References -- Chapter 13: Earth's Insolation and Spatiotemporal Variability of Albedo in the Antarctic -- 13.1 Introduction -- 13.2 Method and Data -- 13.3 Analysis of the Results -- 13.4 Conclusion -- References -- Chapter 14: Quantitative and Productional Characteristics of Microplankton in the Powell Basin and Bransfield Strait in Summer -- 14.1 Introduction -- 14.2 Materials and Methods -- 14.3 Results and Discussion -- 14.3.1 Bacterioplankton -- 14.3.2 Chlorophyll -- 14.3.3 Primary Production -- 14.4 Conclusions -- References -- Chapter 15: Detection of Thermophilic Methanotrophic Microbial Communities in the Water Column of the Bransfield Strait (Antarctica) -- 15.1 Introduction -- 15.2 Study Site, Materials, and Methods -- 15.2.1 DNA Extraction -- 15.2.2 PCR Amplification of pmoA -- 15.2.3 Creation of Enrichment Culture -- 15.2.4 Determination of the Rate of Methane Oxidation in the Stored Culture -- 15.2.5 Gas Chromatography -- 15.3 Results and Discussion -- 15.4 Conclusions -- References -- Chapter 16: Spectral Bio-optical Properties of Waters in the Bransfield Strait and Powell Basin -- 16.1 Introduction -- 16.2 Methods -- 16.3 Results and Discussion -- 16.4 Conclusions -- References -- Chapter 17: Variability of Seawater Optical Properties in the Adjacent Water Basins of the Antarctic Peninsula in January and February 2020 -- 17.1 Introduction -- 17.2 Data and Methods -- 17.3 Results -- 17.3.1 Region of the Falkland (Malvinas) Current -- 17.3.2 Bransfield Strait -- 17.3.3 Antarctic Sound -- 17.4 Conclusions -- References -- Chapter 18: Bio-Optical Models for Estimating Euphotic Zone Depth in the Western Atlantic Sector of the Southern Ocean in the Antarctic Summer -- 18.1 Introduction -- 18.2 Research Region. , 18.3 Measurements and Methods -- 18.4 Results -- 18.4.1 Analysis of the Vertical Distribution of PAR and Calculation of Light Penetration Depths -- 18.4.2 Estimation of Euphotic-Zone Depth from the Surface and Ocean Color Data -- 18.5 Conclusions -- References -- Chapter 19: Phycoerythrin Pigment Distribution in the Upper Water Layer Across the Weddell-Scotia Confluence Zone and Drake Passage -- 19.1 Introduction -- 19.2 Methods and Data -- 19.3 Results and Discussion -- 19.4 Conclusions -- References -- Chapter 20: Nanophytoplankton in the Bransfield Strait: Contribution of Cryptophyta to the Community Abundance and Biomass During Austral Summer -- 20.1 Introduction -- 20.2 Material and Methods -- 20.3 Results and Discussion -- 20.4 Conclusions -- References -- Part III: Section Marine Ecosystems and Their Oceanographical Background -- Chapter 21: Phytopelagic Communities of the Powell Basin in the Summer of 2020 -- 21.1 Introduction -- 21.2 Materials and Methods -- 21.3 Results -- 21.3.1 Phytopelagic Cenoses during the First Stage of the Expedition (January 21, 2020-February 4, 2020) -- 21.3.2 Phytopelagic Cenoses in the Second Stage of the Expedition (February 12-24, 2020) -- 21.4 Discussion -- References -- Chapter 22: Bioluminescence in the Atlantic Sector of the Southern Ocean Based on the Field Observations and Sounding Data -- 22.1 Introduction -- 22.2 Material and Methods -- 22.2.1 Material -- 22.2.2 Biophysical System Salpa-M -- 22.2.3 Bioluminescent Field and Its Characteristics -- 22.3 Results -- 22.3.1 Hydrological Characteristics of the Region -- 22.3.2 Bioluminescence -- References -- Chapter 23: Parasites as an Inseparable Part of Antarctic and Subantarctic Marine Biodiversity -- 23.1 Introduction -- 23.2 Systematic Review of Parasites of the Antarctic and Subantarctic -- 23.3 Faunistic Review of Parasites by Host Groups. , 23.3.1 Invertebrates -- 23.3.2 Vertebrates -- 23.4 Assessment of Parasite Species Diversity in the Antarctic and Subantarctic -- 23.5 Concluding Remarks -- References -- Chapter 24: Spatial Distribution, Species Composition, and Number of Seabirds in the Argentine Basin, Drake Passage, East of Antarctic Peninsula, and Powell Basin in January-March 2020 -- 24.1 Introduction -- 24.2 Materials and Methods -- 24.3 Results -- 24.3.1 Species Composition and General Occurrence -- 24.3.2 Factors Affecting the Occurrence of the Different Species of Seabirds -- 24.3.3 Seabird Distribution in Concordance with the Sea Depth -- 24.3.4 Seabird Distributions Along the Vessel Route -- 24.4 Discussion -- 24.4.1 Factors Affecting the Occurrence of Different Species of Seabirds -- 24.4.2 Seabird Distribution in Concordance with the Sea Depth -- 24.4.3 Spatial and Linear Distributions of Seabirds in the Sea -- 24.5 Conclusions -- References -- Chapter 25: Spatial Distribution, Species Composition, and Number of Marine Mammals in the Argentine Basin, Drake Passage, East of Antarctic Peninsula, and Powell Basin in January-March 2020 -- 25.1 Introduction -- 25.2 Materials and Methods -- 25.3 Results -- 25.3.1 Species Composition -- 25.3.2 Factors Affecting the Occurrence of the Various Species of Marine Mammals -- 25.3.3 Marine Mammal Distribution Correlated with the Sea Depth -- 25.3.4 Marine Mammal Distributions Along the Vessel's Route -- 25.4 Discussion -- 25.4.1 Factors Affecting the Occurrence of the Different Species of Marine Mammals -- 25.4.2 Sea Mammal Distribution Related to the Sea Depth -- 25.4.3 Spatial and Linear Distributions of Sea Mammals -- 25.5 Conclusions -- References -- Chapter 26: Meat in the Ocean: How Much and Who Is to Blame? -- 26.1 Introduction -- 26.2 Materials and Methods -- 26.3 Results -- 26.4 Discussion -- 26.5 Conclusions -- References. , Chapter 27: Macro- and Mesozooplankton in the Powell Basin (Antarctica): Species Composition and Distribution of Abundance and Biomass in February 2020.