Pub Date : 2024-03-01DOI: 10.1134/s0001437023070044
V. A. Glukhov, Yu. A. Goldin, O. V. Glitko, D. I. Glukhovets, E. A. Aglova, M. A. Rodionov
Abstract
A shipborne lidar survey of the western Kara Sea was carried out. The study was performed as part of the first stage of cruise 89 of the R/V Akademik Mstislav Keldysh in September 2022. Simultaneously with the lidar survey, a set of accompanying hydrooptical and hydrological measurements was carried out. Joint statistical analysis of the obtained data made it possible to obtain regression relationships between the lidar attenuation coefficient, seawater beam attenuation coefficient, and diffuse attenuation coefficient. These regression relations are used to convert the spatial distribution of the lidar attenuation coefficient into the seawater beam attenuation coefficient values.
{"title":"Investigation of the Relationships between the Parameters of Lidar Echo Signals and Hydrooptical Characteristics in the Western Kara Sea","authors":"V. A. Glukhov, Yu. A. Goldin, O. V. Glitko, D. I. Glukhovets, E. A. Aglova, M. A. Rodionov","doi":"10.1134/s0001437023070044","DOIUrl":"https://doi.org/10.1134/s0001437023070044","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>A shipborne lidar survey of the western Kara Sea was carried out. The study was performed as part of the first stage of cruise 89 of the R/V <i>Akademik Mstislav Keldysh</i> in September 2022. Simultaneously with the lidar survey, a set of accompanying hydrooptical and hydrological measurements was carried out. Joint statistical analysis of the obtained data made it possible to obtain regression relationships between the lidar attenuation coefficient, seawater beam attenuation coefficient, and diffuse attenuation coefficient. These regression relations are used to convert the spatial distribution of the lidar attenuation coefficient into the seawater beam attenuation coefficient values.</p>","PeriodicalId":54692,"journal":{"name":"Oceanology","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140882269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-01DOI: 10.1134/s0001437023070202
R. Yu. Tarakanov
Abstract—
For the period of satellite altimetry observation 1993–2018, a comparison was made of estimates of the linear meridional shifts of the jet structure and variations in current intensity in the sector of the Antarctic Circumpolar Current (ACC) south of Africa (10° E–25° W), obtained on the basis of the parameters derived from the module of the absolute dynamic topography (ADT) gradient (left| {nabla zeta } right|): directly (left| {nabla zeta } right|), module of the velocity of geostrophic current |u| on the ocean surface, half of square of the ADT gradient (frac{1}{2}{{left| {nabla zeta } right|}^{2}}), and specific kinetic energy (frac{1}{2}{{u}^{2}}). The analysis was carried out by a method developed earlier and refined in this paper using linear regression analysis. It is shown that qualitatively the characters of the meridional shifts (displacement of the curves of these parameters averaged over latitude and for each year) in latitude and the corresponding current intensity variations (i.e., variations in the parameters themselves) over 26-year observations, when calculated through each of the four parameters, turned out to be similar. The same similarity was obtained from the calculations with respect to the ADT scale. Meanwhile, the quantitative differences between calculations for different pairs of parameters can be significant even in the (left| u right|) and (left| {nabla zeta } right|) pair. In quantitative terms, the absolute values of shifts of the jet structure and variations in the intensity of currents in the ACC band in the studied sector of the Southern Ocean generally increase from those linearly dependent on the ADT gradient module to quadratically dependent ones.
摘要-在1993-2018年卫星测高观测期间，比较了非洲以南（东经10°-西经25°）南极环极洋流（ACC）扇区喷流结构线性经向移动和洋流强度变化的估计值，这些估计值是根据绝对动态地形（ADT）梯度模块得出的参数(left| {nabla zeta } right|)得到的：direct (left| {nabla zeta } right|), module of the velocity of geostrophic current |u| on the ocean surface, half of square of the ADT gradient (frac{1}{2}{left| {nabla zeta } right|}^{2}}), and specific kinetic energy (frac{1}{2}{{u}^{2}})。分析采用了早先开发并在本文中改进的线性回归分析方法。结果表明，在 26 年的观测中，通过四个参数的计算，纬度上的经向移动（这些参数的曲线位移在纬度上的平均值和每年的平均值）和相应的海流强度变化（即参数本身的变化）的定性特征是相似的。ADT 尺度的计算结果也是如此。同时，即使在 (left| u right|)和 (left| {nabla zeta } right|)参数对中，不同参数对的计算结果在数量上的差异也是显著的。In quantitative terms, the shifts of the jet structure and variations in the intensity of currents in the ACC band in the studied sector of the Southern Ocean generally increase from those linearly dependent on the ADT gradient module to quadratically dependent ones.
{"title":"Comparative Analysis of Jet Detection Methods on the Basis of Satellite Altimetry Data by Example of the Antarctic Circumpolar Current Sector to the South of Africa","authors":"R. Yu. Tarakanov","doi":"10.1134/s0001437023070202","DOIUrl":"https://doi.org/10.1134/s0001437023070202","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">\u0000<b>Abstract</b>—</h3><p>For the period of satellite altimetry observation 1993–2018, a comparison was made of estimates of the linear meridional shifts of the jet structure and variations in current intensity in the sector of the Antarctic Circumpolar Current (ACC) south of Africa (10° E–25° W), obtained on the basis of the parameters derived from the module of the absolute dynamic topography (ADT) gradient <span>(left| {nabla zeta } right|)</span>: directly <span>(left| {nabla zeta } right|)</span>, module of the velocity of geostrophic current |<i>u</i>| on the ocean surface, half of square of the ADT gradient <span>(frac{1}{2}{{left| {nabla zeta } right|}^{2}})</span>, and specific kinetic energy <span>(frac{1}{2}{{u}^{2}})</span>. The analysis was carried out by a method developed earlier and refined in this paper using linear regression analysis. It is shown that qualitatively the characters of the meridional shifts (displacement of the curves of these parameters averaged over latitude and for each year) in latitude and the corresponding current intensity variations (i.e., variations in the parameters themselves) over 26-year observations, when calculated through each of the four parameters, turned out to be similar. The same similarity was obtained from the calculations with respect to the ADT scale. Meanwhile, the quantitative differences between calculations for different pairs of parameters can be significant even in the <span>(left| u right|)</span> and <span>(left| {nabla zeta } right|)</span> pair. In quantitative terms, the absolute values of shifts of the jet structure and variations in the intensity of currents in the ACC band in the studied sector of the Southern Ocean generally increase from those linearly dependent on the ADT gradient module to quadratically dependent ones.</p>","PeriodicalId":54692,"journal":{"name":"Oceanology","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140882086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-01DOI: 10.1134/s000143702307007x
V. S. Koshkina, A. V. Gavrikov, S. K. Gulev
Abstract
Coherent structures (CSs), which are the most often understood as time-stable vortices, play an important role in the Earth’s climate system, since they make a significant contribution to the processes of momentum and heat and mass transfer of any fluid medium, including the atmosphere and the ocean. This is true for all scales of motion, but is particularly important for more chaotic mesoscale processes. A reliable methodology for identifying mesoscale vortices can potentially stimulate the development of a deterministic climatology of mesoscale processes. The main difficulty in developing this direction is the absence of a rigorously mathematical definition of a vortex, which makes it impossible to automatically search for CSs in spatial data. At the same time, the increase in the spatial resolution of numerical models makes this problem increasingly urgent. Some developments in this direction have been carried out in the field of small-scale turbulence: a number of criteria have been developed that allow for the identification of vortices with varying degrees of reliability. In this paper, the applicability of the three most popular criteria for CS identification in significantly larger-scale geophysical data is studied.
{"title":"Methods of Identifying Atmospheric Mesoscale Coherent Structures Over the North Atlantic","authors":"V. S. Koshkina, A. V. Gavrikov, S. K. Gulev","doi":"10.1134/s000143702307007x","DOIUrl":"https://doi.org/10.1134/s000143702307007x","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Coherent structures (CSs), which are the most often understood as time-stable vortices, play an important role in the Earth’s climate system, since they make a significant contribution to the processes of momentum and heat and mass transfer of any fluid medium, including the atmosphere and the ocean. This is true for all scales of motion, but is particularly important for more chaotic mesoscale processes. A reliable methodology for identifying mesoscale vortices can potentially stimulate the development of a deterministic climatology of mesoscale processes. The main difficulty in developing this direction is the absence of a rigorously mathematical definition of a vortex, which makes it impossible to automatically search for CSs in spatial data. At the same time, the increase in the spatial resolution of numerical models makes this problem increasingly urgent. Some developments in this direction have been carried out in the field of small-scale turbulence: a number of criteria have been developed that allow for the identification of vortices with varying degrees of reliability. In this paper, the applicability of the three most popular criteria for CS identification in significantly larger-scale geophysical data is studied.</p>","PeriodicalId":54692,"journal":{"name":"Oceanology","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140882293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-01DOI: 10.1134/s0001437023070184
P. A. Shabanov, A. V. Baranskaya
Abstract
The features of the spatial distribution of the long-term average ice-free period (IFP) characteristics and their trends in the Laptev Sea are calculated and described quantitatively based on the microwave remote sensing data for 1979–2021. The spatial distribution of the long-term average duration of the IFP mainly follows the spatial distribution of the long-term average IFP start dates. The highest value of the long-term average duration of the IFP is observed in the areas where the Anabar–Lena and Western New Siberian stationary flaw polynyas are formed. It is shown that south of 78° N, the duration of the IFP increased statistically significantly by +17 ± 7 days/10 year on average. The areas of the Laptev Sea north of 80° N are characterized by statistically insignificant changes in IFP characteristics. The duration of the IFP extends due to both the shift of the IFP start dates to the earlier time (an average rate of changes is –10 ± 4 days/10 year) and the shift of the IFP end dates to a later time (an average rate of changes is +8 ± 4 days/10 year).
{"title":"Extension of the Ice-Free Period in the Laptev Sea According to Remote Sensing Data","authors":"P. A. Shabanov, A. V. Baranskaya","doi":"10.1134/s0001437023070184","DOIUrl":"https://doi.org/10.1134/s0001437023070184","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The features of the spatial distribution of the long-term average ice-free period (IFP) characteristics and their trends in the Laptev Sea are calculated and described quantitatively based on the microwave remote sensing data for 1979–2021. The spatial distribution of the long-term average duration of the IFP mainly follows the spatial distribution of the long-term average IFP start dates. The highest value of the long-term average duration of the IFP is observed in the areas where the Anabar–Lena and Western New Siberian stationary flaw polynyas are formed. It is shown that south of 78° N, the duration of the IFP increased statistically significantly by +17 ± 7 days/10 year on average. The areas of the Laptev Sea north of 80° N are characterized by statistically insignificant changes in IFP characteristics. The duration of the IFP extends due to both the shift of the IFP start dates to the earlier time (an average rate of changes is –10 ± 4 days/10 year) and the shift of the IFP end dates to a later time (an average rate of changes is +8 ± 4 days/10 year).</p>","PeriodicalId":54692,"journal":{"name":"Oceanology","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140019778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-01DOI: 10.1134/s0001437023070068
K. D. Korobchenkova, S. V. Aleksandrov, A. S. Semenova, Zh. I. Stont, M. O. Ulyanova
Abstract
The patterns of changes in the composition and quantity of zooplankton and concentration of chlorophyll a in the estuary of the Pregolya River and adjacent waters of the Baltic Sea are considered depending on hydrological and meteorological conditions in 2021–2022. Three zones of the estuary were identified: estuarine, mixing, and marine. In the water mixing zone, there are salinity gradients, the position of which is influenced by wind forcing and river discharge. The largest concentration of chlorophyll a was noted in the estuarine zone and at the boundary of the water mixing zone, where the flow of nutrients from the drainage area is most noticeable. The removal of water from the lagoon affects the concentration of chlorophyll a and the composition of zooplankton. The estuarine zone is characterized by the highest level of eutrophication, where it approaches the threshold of hypertrophy; in the marine zone, the concentrations of chlorophyll a corresponded to eutrophic water. Depending on the inflow–outflow phenomena, the proportion of zooplankton species differs in relation to changes in salinity, and there is a sharp increase in deaths of organisms of species not adapted to a given salinity.
摘要 根据 2021-2022 年的水文和气象条件，研究了普雷戈利亚河河口及波罗的海邻近水域浮游动物的组成和数量以及叶绿素 a 浓度的变化规律。确定了河口的三个区域：河口区、混合区和海洋区。在水体混合区，存在盐度梯度，其位置受风力和河流排水量的影响。叶绿素 a 的最大浓度出现在河口区和水体混合区的边界，这里是排水区营养物质流动最明显的地方。泻湖的水量减少会影响叶绿素 a 的浓度和浮游动物的组成。河口区的富营养化程度最高，接近富营养化临界值；在海洋区，叶绿素 a 的浓度与富营养化水体相对应。根据流入-流出现象，浮游动物物种的比例随盐度的变化而变化，不适应特定盐度的物种的死亡数量急剧增加。
{"title":"Influence of Hydrometeorological Conditions on the Plankton Distribution in the Estuary of the Pregolya River and the Coastal Part of the Baltic Sea","authors":"K. D. Korobchenkova, S. V. Aleksandrov, A. S. Semenova, Zh. I. Stont, M. O. Ulyanova","doi":"10.1134/s0001437023070068","DOIUrl":"https://doi.org/10.1134/s0001437023070068","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The patterns of changes in the composition and quantity of zooplankton and concentration of chlorophyll <i>a</i> in the estuary of the Pregolya River and adjacent waters of the Baltic Sea are considered depending on hydrological and meteorological conditions in 2021–2022. Three zones of the estuary were identified: estuarine, mixing, and marine. In the water mixing zone, there are salinity gradients, the position of which is influenced by wind forcing and river discharge. The largest concentration of chlorophyll <i>a</i> was noted in the estuarine zone and at the boundary of the water mixing zone, where the flow of nutrients from the drainage area is most noticeable. The removal of water from the lagoon affects the concentration of chlorophyll <i>a</i> and the composition of zooplankton. The estuarine zone is characterized by the highest level of eutrophication, where it approaches the threshold of hypertrophy; in the marine zone, the concentrations of chlorophyll <i>a</i> corresponded to eutrophic water. Depending on the inflow–outflow phenomena, the proportion of zooplankton species differs in relation to changes in salinity, and there is a sharp increase in deaths of organisms of species not adapted to a given salinity.</p>","PeriodicalId":54692,"journal":{"name":"Oceanology","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140882297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-01DOI: 10.1134/s0001437023070093
L. V. Malakhova, V. V. Voitsekhovskaia, T. V. Malakhova
Abstract—
From 2010 to 2022, the summed concentrations of six indicator polychlorinated biphenyls (∑6PCB) and DDT with metabolites DDE and DDD (∑DDT) in the surface layer of the coastal Black Sea areas of Crimea varied from 0.05 to 34.9 and from 0.01 to 7.44 ng/L, respectively. The maximum concentrations of both groups of compounds were found during spring seasons. With the total variability in the ∑DDT content in water being significant, their average concentration tended to decrease in the study period. For PCBs, this trend was not detected. The ∑DDT concentration in mesozooplankton in the studied water areas in 2016, 2017, and 2019 reached 34.3; ∑6PCB, 475 ng/g dry weight. A positive correlation between the ∑DDT concentration in mesozooplankton and water samples (R2 = 0.77) and the lack of such correlation for ∑PCB (R2 = 0.03) was revealed. It was determined that the accumulation of ∑PCB and ∑DDT in mesozooplankton was directly correlated with the total lipid content in organisms. In the surface layer of sediments in open areas of the Black Sea water area of Crimea, the content of PCB congeners 101, 138, 153, and 180 was the same in 2016 and 2019, which indicates stabilization of the technogenic load on the studied water areas.
{"title":"Organochlorine Pollutants in Components of the Black Sea Coastal Areas Ecosystem of Crimea from 2010 to 2022","authors":"L. V. Malakhova, V. V. Voitsekhovskaia, T. V. Malakhova","doi":"10.1134/s0001437023070093","DOIUrl":"https://doi.org/10.1134/s0001437023070093","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">\u0000<b>Abstract</b>—</h3><p>From 2010 to 2022, the summed concentrations of six indicator polychlorinated biphenyls (∑6PCB) and DDT with metabolites DDE and DDD (∑DDT) in the surface layer of the coastal Black Sea areas of Crimea varied from 0.05 to 34.9 and from 0.01 to 7.44 ng/L, respectively. The maximum concentrations of both groups of compounds were found during spring seasons. With the total variability in the ∑DDT content in water being significant, their average concentration tended to decrease in the study period. For PCBs, this trend was not detected. The ∑DDT concentration in mesozooplankton in the studied water areas in 2016, 2017, and 2019 reached 34.3; ∑6PCB, 475 ng/g dry weight. A positive correlation between the ∑DDT concentration in mesozooplankton and water samples (<i>R</i> <sup>2</sup> = 0.77) and the lack of such correlation for ∑PCB (<i>R</i> <sup>2</sup> = 0.03) was revealed. It was determined that the accumulation of ∑PCB and ∑DDT in mesozooplankton was directly correlated with the total lipid content in organisms. In the surface layer of sediments in open areas of the Black Sea water area of Crimea, the content of PCB congeners 101, 138, 153, and 180 was the same in 2016 and 2019, which indicates stabilization of the technogenic load on the studied water areas.</p>","PeriodicalId":54692,"journal":{"name":"Oceanology","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140881850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-01DOI: 10.1134/s0001437023070160
D. V. Ryabchuk, E. E. Taldenkova, A. Yu. Sergeev, V. A. Zhamoida, L. M. Budanov, D. V. Prishchepenko, E. S. Nosevich, Ya. E. Terekhina, L. D. Bashirova, E. P. Ponomarenko, I. A. Neevin, A. V. Chekulaev, A. G. Grigoriev
Abstract
Problems of the paleogeographical evolution and changes in sedimentation environment within the Indigirka River paleovalley (the East Siberian Sea) are discussed. Based on the results of geophysical and geological research and a high-resolution study of sediment cores (grain size analysis, geochemistry, macro- and micropaleontology, pollen analysis, radiocarbon dating) the development of the Holocene marine transgression has been reconstructed, sedimentation rates have been calculated, and the basic principles of changes in sedimentation processes have been established.
{"title":"Sedimentation Processes and the Holocene Evolution of the Indigirka Paleovalley (Coastal Shelf Area of the East Siberian Sea)","authors":"D. V. Ryabchuk, E. E. Taldenkova, A. Yu. Sergeev, V. A. Zhamoida, L. M. Budanov, D. V. Prishchepenko, E. S. Nosevich, Ya. E. Terekhina, L. D. Bashirova, E. P. Ponomarenko, I. A. Neevin, A. V. Chekulaev, A. G. Grigoriev","doi":"10.1134/s0001437023070160","DOIUrl":"https://doi.org/10.1134/s0001437023070160","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Problems of the paleogeographical evolution and changes in sedimentation environment within the Indigirka River paleovalley (the East Siberian Sea) are discussed. Based on the results of geophysical and geological research and a high-resolution study of sediment cores (grain size analysis, geochemistry, macro- and micropaleontology, pollen analysis, radiocarbon dating) the development of the Holocene marine transgression has been reconstructed, sedimentation rates have been calculated, and the basic principles of changes in sedimentation processes have been established.</p>","PeriodicalId":54692,"journal":{"name":"Oceanology","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140882273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-01DOI: 10.1134/s0001437023070020
A. V. Drits, A. F. Pasternak, E. G. Arashkevich, A. B. Amelina, T. A. Shchuka, M. V. Flint
Abstract—
A characteristic feature of the eastern Kara Sea, which is separated from its central part by the shallow Central Kara Rise, is a later ice breakup, a shorter ice-free period, and lower water temperature. Zooplankton in this part of the sea is virtually unstudied. The first data on the composition, spatial distribution of zooplankton, age structure and feeding of the dominant species, and their grazing impact on phytoplankton were obtained in the cruise 125 of the R/V Professor Shtokman (September 2013) and cruise 63 of the R/V Akademik Mstislav Keldysh (September 2015) to the eastern Kara Sea. 2015 was a typical year in terms of the ice regime for this region, while in 2013, seasonal ice coverage lasted longer than usual. Zooplankton biomass (17–112 mg dry weight m–3), to which copepods Calanus glacialis contributed the main portion, were close to the values in the central Kara Sea in September. The seasonal development of the C. glacialis population began much later than in the central Kara Sea, but development of Metridia longa was not influenced by the specifics of the ice regime and hydrophysical conditions in the eastern Kara Sea. The interannual differences in the timing of ice retreat had almost no effect on the zooplankton abundance, seasonal development of the dominant copepod populations, feeding activity, and grazing impact on phytoplankton.
{"title":"Zooplankton of the Eastern Kara Sea: Response to a Short Ice-Free Period","authors":"A. V. Drits, A. F. Pasternak, E. G. Arashkevich, A. B. Amelina, T. A. Shchuka, M. V. Flint","doi":"10.1134/s0001437023070020","DOIUrl":"https://doi.org/10.1134/s0001437023070020","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">\u0000<b>Abstract</b>—</h3><p>A characteristic feature of the eastern Kara Sea, which is separated from its central part by the shallow Central Kara Rise, is a later ice breakup, a shorter ice-free period, and lower water temperature. Zooplankton in this part of the sea is virtually unstudied. The first data on the composition, spatial distribution of zooplankton, age structure and feeding of the dominant species, and their grazing impact on phytoplankton were obtained in the cruise 125 of the R/V <i>Professor Shtokman</i> (September 2013) and cruise 63 of the R/V <i>Akademik Mstislav Keldysh</i> (September 2015) to the eastern Kara Sea. 2015 was a typical year in terms of the ice regime for this region, while in 2013, seasonal ice coverage lasted longer than usual. Zooplankton biomass (17–112 mg dry weight m<sup>–3</sup>), to which copepods <i>Calanus glacialis</i> contributed the main portion, were close to the values in the central Kara Sea in September. The seasonal development of the <i>C. glacialis</i> population began much later than in the central Kara Sea, but development of <i>Metridia longa</i> was not influenced by the specifics of the ice regime and hydrophysical conditions in the eastern Kara Sea. The interannual differences in the timing of ice retreat had almost no effect on the zooplankton abundance, seasonal development of the dominant copepod populations, feeding activity, and grazing impact on phytoplankton.</p>","PeriodicalId":54692,"journal":{"name":"Oceanology","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140019782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-01DOI: 10.1134/s0001437023070135
A. A. Paraskiv, N. N. Tereshchenko, V. Yu. Proskurnin, O. D. Chuzhikova-Proskurnina, M. O. Vakhrushev
Abstract
The article presents the results of a quantitative determination of the migration and distribution fluxes of plutonium radioisotopes 239 + 240Pu in coastal semiclosed marine ecosystems from a case study example of Sevastopol Bay (Black Sea) to assess the self-purification of water masses from 239 + 240Pu. The assessment was based on a study of the current (2018–2021) levels of the activity concentration of 239 + 240Pu in water, bottom sediments, perennial brown macroalgae, and benthic fish. It has been found that the main 239 + 240Pu removal flux (more than 93% of the total flux), which determines the self-purification of water masses with respect to 239 + 240Pu in coastal marine areas is the sediment flux of suspended particle matter, which causes redistribution of 239 + 240Pu into bottom sediments. 239 + 240Pu migration to neighboring water areas due to hydrological processes is insignificant, as well as the decrease in 239 + 240Pu in the ecosystem due to radioactive decay. In total, these processes accounted for less than 1% of the total flux. The interaction of 239 + 240Pu with macrobiota accounted for almost 6%, of which more than 5% was provided by macrophytes.
{"title":"Migration and Distribution Fluxes of Plutonium Radioisotopes in Coastal Semiclosed Marine Areas","authors":"A. A. Paraskiv, N. N. Tereshchenko, V. Yu. Proskurnin, O. D. Chuzhikova-Proskurnina, M. O. Vakhrushev","doi":"10.1134/s0001437023070135","DOIUrl":"https://doi.org/10.1134/s0001437023070135","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The article presents the results of a quantitative determination of the migration and distribution fluxes of plutonium radioisotopes <sup>239 + 240</sup>Pu in coastal semiclosed marine ecosystems from a case study example of Sevastopol Bay (Black Sea) to assess the self-purification of water masses from <sup>239 + 240</sup>Pu. The assessment was based on a study of the current (2018–2021) levels of the activity concentration of <sup>239 + 240</sup>Pu in water, bottom sediments, perennial brown macroalgae, and benthic fish. It has been found that the main <sup>239 + 240</sup>Pu removal flux (more than 93% of the total flux), which determines the self-purification of water masses with respect to <sup>239 + 240</sup>Pu in coastal marine areas is the sediment flux of suspended particle matter, which causes redistribution of <sup>239 + 240</sup>Pu into bottom sediments. <sup>239 + 240</sup>Pu migration to neighboring water areas due to hydrological processes is insignificant, as well as the decrease in <sup>239 + 240</sup>Pu in the ecosystem due to radioactive decay. In total, these processes accounted for less than 1% of the total flux. The interaction of <sup>239 + 240</sup>Pu with macrobiota accounted for almost 6%, of which more than 5% was provided by macrophytes.</p>","PeriodicalId":54692,"journal":{"name":"Oceanology","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140882085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-01DOI: 10.1134/s0001437023070214
D. A. Iakovleva, I. L. Bashmachnikov, N. A. Diansky
Abstract
The interannual variability of deep convection in the Irminger Sea is considered essential in controlling the intensity of the Atlantic Meridional Overturning Circulation (AMOC). Based on the ARMOR-3D oceanic dataset and the Era-Interim atmospheric reanalysis, we suggest that the oceanic heat advection in the sea of the Irminger Current governs the interdecadal variability of deep convection of the Irminger Sea by modulating the upper ocean heat content in the basin. This forms a negative feedback that stabilizes the AMOC: an increase in the advection of oceanic heat into the Irminger Sea leads to a decrease in the convection depth, which further reduces the northward heat transport by the AMOC. We suggest that, on interdecadal time scales, the effect of ocean–atmosphere heat exchange on deep convection is relatively small due to a much lower interannual variability of the former compared to that of the oceanic heat convergence. During the positive phase of the North Atlantic Oscillation (NAO), the Irminger Current becomes colder, which allows an alternative explanation for the intermittently observed intensification of convection in the Irminger Sea with an increase in the NAO index. Thus, the long-period variability of the convection intensity in the Irminger Sea is associated not with local atmospheric influence, but rather with remote atmospheric forcing.
{"title":"Coherence of Deep Convection in the Irminger Sea with Oceanic Heat Advection","authors":"D. A. Iakovleva, I. L. Bashmachnikov, N. A. Diansky","doi":"10.1134/s0001437023070214","DOIUrl":"https://doi.org/10.1134/s0001437023070214","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The interannual variability of deep convection in the Irminger Sea is considered essential in controlling the intensity of the Atlantic Meridional Overturning Circulation (AMOC). Based on the ARMOR-3D oceanic dataset and the Era-Interim atmospheric reanalysis, we suggest that the oceanic heat advection in the sea of the Irminger Current governs the interdecadal variability of deep convection of the Irminger Sea by modulating the upper ocean heat content in the basin. This forms a negative feedback that stabilizes the AMOC: an increase in the advection of oceanic heat into the Irminger Sea leads to a decrease in the convection depth, which further reduces the northward heat transport by the AMOC. We suggest that, on interdecadal time scales, the effect of ocean–atmosphere heat exchange on deep convection is relatively small due to a much lower interannual variability of the former compared to that of the oceanic heat convergence. During the positive phase of the North Atlantic Oscillation (NAO), the Irminger Current becomes colder, which allows an alternative explanation for the intermittently observed intensification of convection in the Irminger Sea with an increase in the NAO index. Thus, the long-period variability of the convection intensity in the Irminger Sea is associated not with local atmospheric influence, but rather with remote atmospheric forcing.</p>","PeriodicalId":54692,"journal":{"name":"Oceanology","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140019600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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