Currents in the Western Part of the Weddell Sea and Drift of Large Iceberg A68A

Morozov, Eugene G.; Krechik, V. А.; Frey, D. I.; Замшин, В. В.

doi:10.1134/s000143702105009x

Cited by 6 publications

(3 citation statements)

References 32 publications

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“…It was recently shown that this melted water leads to an increase in vertical stability, prevents vertical mixing, and provides conditions for the development of biological communities in the studied region of the Weddell Sea [44]. The melting of icebergs can also affect the thermohaline structure of the upper ocean layer and contribute to the observed increase in biological productivity [45].…”

Section: Discussionmentioning

confidence: 98%

Comparative Analysis of the Fatty Acid Profiles of Antarctic Krill (Euphausia superba Dana, 1850) in the Atlantic Sector of the Southern Ocean: Certain Fatty Acids Reflect the Oceanographic and Trophic Conditions of the Habitat

Murzina,

Voronin,

Bitiutskii

et al. 2023

JMSE

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The present study is the attempt to combine oceanologic measurements and biochemical analysis, which is as possible to implement on board as in a laboratory with chosen certain statistics to reveal trophic conditions and the environment state in which Antarctic krill live in season in real time on site. The fatty acid constituents of total lipids in juvenile and mature Antarctic krill sampled from the Bransfield Strait (BS), the Antarctic Sound (AS), and waters at the eastern tip of the Antarctic Peninsula (AP) collected during the 87th cruise of the R/V Akademik Mstislav Keldysh in January–February 2022 were analyzed. The fatty acid (FA) profile in juvenile and mature Antarctic krill was studied by gas chromatography with a mass selective detector to identify the qualitative composition and a flame ionization detector to quantify the studied FAs. Using NMDS analysis (quantitative panel), great difference was found between krill from the BS compared to krill collected in the AS and the AP. The differences are reliable owing to the following 16 FAs, most of them trophic biomarkers of microphytoplankton, and suggest regional differences, mainly in abundance and ability of forage objects. CTD measurements discuss the abiotic factors (potential temperature, salinity, and chlorophyll “a”). Compensatory modifications of the composition of FA components in Antarctic krill inhabiting different water areas are a way of maintaining the species’ viability under certain and variable habitat conditions.

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Section: Discussionmentioning

confidence: 98%

Comparative Analysis of the Fatty Acid Profiles of Antarctic Krill (Euphausia superba Dana, 1850) in the Atlantic Sector of the Southern Ocean: Certain Fatty Acids Reflect the Oceanographic and Trophic Conditions of the Habitat

Murzina,

Voronin,

Bitiutskii

et al. 2023

JMSE

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“…The dataset was divided into 5 categories, namely, sea ice (firstyear ice), icebreakers, icebergs, inter-ice waterways, and melting pools on ice. Labellmg, an image annotation tool, was used to label the images as fy, icebreaker, iceberg, channel, and pool, respectively [20,21]. Finally, the dataset is randomly divided into training and testing sets at the ratio of 8:2.…”

Section: Construction Of a Local-scale Polar Multi-target Datasetmentioning

confidence: 99%

Multi-Scale Polar Object Detection Based on Computer Vision

Ding,

Zeng,

Zhou

et al. 2023

Water

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When ships navigate in polar regions, they may collide with ice masses, which may cause structural damage and endanger the safety of their occupants. Therefore, it is essential to promptly detect sea ice, icebergs, and passing ships. However, individual data sources have limits and should be combined and integrated to obtain more thorough information. A polar multi-target local-scale dataset with five categories was constructed. Sea ice, icebergs, ice melt ponds, icebreakers, and inter-ice channels were identified by a single-shot detector (SSD), with a final mAP value of 70.19%. A remote sensing sea ice dataset with 15,948 labels was constructed. The You Only Look Once (YOLOv5) model was improved with Squeeze-and-Excitation Networks (SE), Funnel Activation (FReLU), Fast Spatial Pyramid Pooling, and Cross Stage Partial Network (SPPCSPC-F). In the detection stage, a slicing operation was performed on remote sensing images to detect small targets. Simulated sea ice data were included to verify the model’s generalization ability. Then, the improved model was trained and evaluated in an ablation experiment. The mAP, recall (R), and precision (P) values of the improved YOLOv5 were 75.3%, 70.3, and 75.4%, with value increases of 3.5%, 3.4%, and 1.9%, respectively, compared to the original model. The improved YOLOv5 was also compared with other models such as YOLOv3, Faster-RCNN, and YOLOv4-tiny. The results indicated that the performance of the proposed model surpassed those of the other conventional models. This study achieved the detection of multiple targets on different scales in a polar region and realized data fusion, avoiding the limitations of using a single data source, and provides a method to support polar ship path planning.

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“…Although not well constrained by observations, high-latitude precipitation is likely to increase in a warming climate, consistent with an increase in the capacity of warmer air to hold and transport moisture [ 20 ]. The impact of icebergs has been the focus of significant attention recently, due at least partly to the gigantic (initially 5719 ± 77 km 2 ) A68 iceberg that calved in 2017, and that exited the Weddell Sea and reached the shelf of South Georgia before disintegrating in 2021 [ 9 , 21 ].…”

Section: Introductionmentioning

confidence: 99%

Tracing the impacts of recent rapid sea ice changes and the A68 megaberg on the surface freshwater balance of the Weddell and Scotia Seas

Meredith

Abrahamsen

Haumann

et al. 2023

Phil. Trans. R. Soc. A.

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The Southern Ocean upper-layer freshwater balance exerts a global climatic influence by modulating density stratification and biological productivity, and hence the exchange of heat and carbon between the atmosphere and the ocean interior. It is thus important to understand and quantify the time-varying freshwater inputs, which is challenging from measurements of salinity alone. Here we use seawater oxygen isotopes from samples collected between 2016 and 2021 along a transect spanning the Scotia and northern Weddell Seas to separate the freshwater contributions from sea ice and meteoric sources. The unprecedented retreat of sea ice in 2016 is evidenced as a strong increase in sea ice melt across the northern Weddell Sea, with surface values increasing approximately two percentage points between 2016 and 2018 and column inventories increasing approximately 1 to 2 m. Surface meteoric water concentrations exceeded 4% in early 2021 close to South Georgia due to meltwater from the A68 megaberg; smaller icebergs may influence meteoric water at other times also. Both these inputs highlight the importance of a changing cryosphere for upper-ocean freshening; potential future sea ice retreats and increases in iceberg calving would enhance the impacts of these freshwater sources on the ocean and climate. This article is part of a discussion meeting issue ‘Heat and carbon uptake in the Southern Ocean: the state of the art and future priorities’.

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Currents in the Western Part of the Weddell Sea and Drift of Large Iceberg A68A

Cited by 6 publications

References 32 publications

Comparative Analysis of the Fatty Acid Profiles of Antarctic Krill (Euphausia superba Dana, 1850) in the Atlantic Sector of the Southern Ocean: Certain Fatty Acids Reflect the Oceanographic and Trophic Conditions of the Habitat

Comparative Analysis of the Fatty Acid Profiles of Antarctic Krill (Euphausia superba Dana, 1850) in the Atlantic Sector of the Southern Ocean: Certain Fatty Acids Reflect the Oceanographic and Trophic Conditions of the Habitat

Multi-Scale Polar Object Detection Based on Computer Vision

Tracing the impacts of recent rapid sea ice changes and the A68 megaberg on the surface freshwater balance of the Weddell and Scotia Seas

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