Role of Zooplankton in the Vertical Mass Flux in the Kara and Laptev Seas in Fall

The role of zooplankton in the vertical mass flux in the Kara and Laptev seas was studied during cruise 63 of the R/V Akademik Mstislav Keldysh in August–October 2015. Mass fluxes were estimated using sediment trap samples. The maximum values of the total vertical flux (19600 mg m^?2 day^?1) and particulate organic carbon (POC) flux (464 mg C m^?2 day^?1) were measured close to the Lena River Delta in the Laptev Sea. In the Kara Sea, the total flux (80–2700 mg m^?2 day^?1) and the POC flux (17–130 mg C m^?2 day^?1) were substantially higher than the estimates published earlier. The fecal pellet flux varied from 2 to 92 mg C m^?2 day^?1 and made up 4–190% of the total organic carbon flux. The mineral composition of fecal pellets largely mirrored that of suspended particulate matter. Clay minerals in the fecal pellets were more abundant than in particulate matter in the areas with noticeable freshwater impact. The flux of zooplankton carcasses varied from 0.1 to 66.4 mg C m^?2 day^?1 and made up 0.2–72% of total POC flux. The results are discussed in relation to the abundance and composition of zooplankton, the concentration and composition of suspended particulate matter, hydrophysical conditions, and methods of sample preparation for analysis.     

Atlantic Water flow through the Barents and Kara Seas

The pathway and transformation of water from the Norwegian Sea across the Barents Sea and through the St. Anna Trough are documented from hydrographic and current measurements of the 1990s. The transport through an array of moorings in the north-eastern Barents Sea was between 0.6 Sv in summer and 2.6 Sv in winter towards the Kara Sea and between zero and 0.3 Sv towards the Barents Sea with a record mean net flow of 1.5 Sv. The westward flow originates in the Fram Strait branch of Atlantic Water at the Eurasian continental slope, while the eastward flow constitutes the Barents Sea branch, continuing from the western Barents Sea opening.About 75% of the eastward flow was colder than 0°C. The flow was strongly sheared, with the highest velocities close to the bottom. A deep layer with almost constant temperature of about −0.5°C throughout the year formed about 50% of the flow to the Kara Sea. This water was a mixture between warm saline Atlantic Water and cold, brine-enriched water generated through freezing and convection in polynyas west of Novaya Zemlya, and possibly also at the Central Bank. Its salinity is lower than that of the Atlantic Water at its entrance to the Barents Sea, because the ice formation occurs in a low salinity surface layer. The released brine increases the salinity and density of the surface layer sufficiently for it to convect, but not necessarily above the salinity of the Atlantic Water. The freshwater west of Novaya Zemlya primarily stems from continental runoff and at the Central Bank probably from ice melt. The amount of fresh water compares to about 22% of the terrestrial freshwater supply to the western Barents Sea. The deep layer continues to the Kara Sea without further change and enters the Nansen Basin at or below the core depth of the warm, saline Fram Strait branch. Because it is colder than 0°C it will not be addressed as Atlantic Water in the Arctic Ocean.In earlier decades, the Atlantic Water advected from Fram Strait was colder by almost 2 K as compared to the 1990s, while the dense Barents Sea water was colder by up to 1 K only in a thin layer at the bottom and the salinity varied significantly. However, also with the resulting higher densities, deep Eurasian Basin water properties were met only in the 1970s. The very low salinities of the Great Salinity Anomaly in 1980 were not discovered in the outflow data. We conclude that the thermal variability of inflowing Atlantic water is damped in the Barents Sea, while the salinity variation is strongly modified through the freshwater conditions and ice growth in the convective area off Novaya Zemlya.     

Features of the Behavior of Organic Compounds in Water and Bottom Sediments in the Kara Sea during Seasonal Ice Melting

Oceanology - The article presents the first data on the content of organic compounds (OCs): Corg, lipids, and hydrocarbons (aliphatic—AHCs) and polycyclic aromatic (PAHs)) in suspended...     

Comparative Characterization of Techniques for Pore Water Sampling from Bottom Sediments and Permafrost Rocks from Buor-Khaya Bay (Laptev Sea)

Oceanology - A comparative analysis of pore water composition using different methods of sampling from bottom sediments and permafrost rocks from Buor-Khaya Bay (Laptev Sea) was carried out. The...     

Radiation-Geochemical Stability of Bottom Sediments in the Ob and Yenisei Estuaries and Adjacent Shoal Area of the Kara Sea

Oceanology - This paper reports the results of investigations on the radioecological state of bottom sediments of the Ob–Yenisei shoal area and Ob and Yenisei estuaries. Materials were...     

Warm-Water Planktonic Foraminifera in Kara Sea Sediments

Oceanology - The article is devoted to research of warm-water planktonic foraminifera species in the Arctic. The fauna of planktonic and benthic foraminifera in the surface and subsurface layer of...     

Distribution Patterns of Methane,Hydrogen, and Helium in the Water Column of the Kara Sea

Oceanology - Estimates of the content of dissolved methane, hydrogen, and helium in seawater of the Kara Sea were obtained. It was found that the methane concentration in the studied areas varied...     

Zooplankton Composition and Trophic Status of Aquatic Species in the Laptev and East Siberian Seas

Oceanology - The species composition, abundance, biomass, and distribution of zooplankton were studied on the shelf and slope of the northwestern Laptev Sea and the shelf of the East Siberian Sea...     

Heterotrophic Nanoflagellates in the Pelagic Zone and Sediments of the Eastern Laptev Sea

Oceanology - For the first time, the species composition of heterotrophic nanoflagellates, their quantitative characteristics, and abundance and biomass of their main food objects—bacteria...     

Process of Postglacial Transgression on the Coasts of the East Siberian and Laptev Seas

Oceanology - The width of shelves and continental slopes of the East Siberian and Laptev seas affected the postglacial transgression. This dependence, in turn, is directly determined by the...     

广东近岸海域矿物特征指数分布及指示意义

在从“源”到“汇”的沉积物输运过程中,近岸海域由于接近沉积物的源头,沉积物的物质组成相似程度较高,沉积动力环境复杂,难以用元素化学和矿物组成特征等方法区分沉积物的分布规律和控制因素。通过分析珠江口及其周边海域表层沉积物的碎屑矿物含量及特征指数发现,成分成熟度和物源区指数的分布特征主要受物源组分的影响,而ZTR指数的分布特征能够明显体现出水动力条件的分选作用对沉积物分布的影响;重矿物分异指数对海域内的水动力变化趋势的反映最敏锐。由此可见,在物源组成相似程度较高的近岸海域,碎屑矿物的特征指数分析能够作为一种反映物源相似程度较高的近岸海域内沉积物的分布规律及其影响因素的分析方法。     

Mapping the sedimentary basins of the Barents and Kara Seas using ERS-1 altimetry-geodetic mission

The continental shelf in the Arctic north of Russia consists of a series of epicontinental seas, which are the offshore continuation of potentially oil and gas basins on land. The geology of all these epicontinental seas is poorly known, due to the remoteness, the extreme climatic conditions and the extensive costs associated with seismic exploration. Radar altimeter sensors thus provide an invaluable tool for studying the geological structures off the coast. The unique ERS-1 contribution comes from its high latitude coverage (81.5 deg south to north), and the space and time density of its measurements (168-day repeat-orbit).The gravity anomaly field is derived from the geoid height measurements by computing the deflections of the vertical in the north-south and east-west directions and transforming these deflections into gravity anomalies. The gravimetry reveals interesting features of the basement of the Barents and Kara Seas which have not been chartered in recent, previous compilation maps of sedimentary thickness in the Arctic Ocean (Jackson and Oakey, 1988; Gramberg and Puscharovski, 1989). We obtain no indication of the SE-NW offshore Baikalian trend described by Fichler et al (1997) using ERS-1 gravimetry. Instead, the data indicate the presence of a north-south trending gravity high associated with the maximum sediment thickness within the South Barents Sea and the North Barents Sea Basins. Further geological studies are needed to interpret the gravimetric data, which directly addresses the problem of understanding the gravity signature of deep, old, sedimentary basins.     

Components of Oil Pollution in Water and Bottom Sediments of the Northeastern Part of the Russian Black Sea Region

Oceanology - The results of studies of oil pollution (by the sum of hydrocarbons and resinous substances) of water and bottom sediments in the northeast Black Sea in spring and autumn are...     

Pollutant Accumulation Areas in Barents Sea Bottom Sediments

Oceanology - The issue of identifying pollutant accumulation areas in Barents Sea sediments was considered based on years-long research (2002–2018) conducted by PINRO. GIS technology and...     

Bottom Communities of Sedova Bay (Novaya Zemlya,the Kara Sea)

Oceanology - The benthic fauna of Sedova Bay (Kara Sea, Novaya Zemlya Archipelago) was studied during two cruises of the R/V Academik Mstislav Keldysh in 2015–2016. Three macrobenthic...     

黄海、渤海底层盐度预报方法的研究

根据二维流体动力学方程和深度平均盐度扩散方程在河口径流量以及蒸发和降水之差为已知情况下构成的闭合方程组，预报出深度平均盐度，然后利用底层盐度与深度平均盐度、水深和时间（月）之间的经验关系，给出底层盐度的二维预报。为了检验试报结果的可靠性，文中将黄渤海底层盐度的试报结果（１９７年７月１１日，时效为３ｄ）与标准断面观测资料（７月１１日观测，１２４．５°Ｅ以西，共１０４站）作一粗略比较。比较表明，试报结果与实测值的相关系数为０．９６，均方误差为σ＝０．２６，绝对误差小于０．２和０．３的站数分别占总站数的６３．５×１０－２和７７．０×１０－２，而总均绝差为０．１９。由此可见，试报的效果是令人满意的。     

用自回归预报黄渤海的底层水温

用自回归模型,对覆盖渤海标准水文断面上的２９个站和北黄海的１０个站的底层海水温度进行了预报。均方误差为０．７５℃,结果较好,方法简便,能够满足渔业生产的需要。     

Features of Bitumoid Distribution in Bottom Sediments of the Barents Sea

Oceanology - The results on the content, composition, and distribution of chloroform bitumoids (CBs) in the Holocene sediments of the Barents Sea are presented (Cruise 68 of the R/V Akademik...     

黄海、渤海底层温度数值预报方法的研究

根据文献［ｌ］建立的底层温度（ＴＨ）与其水柱垂向平均温度（）的经验关系，结合流体动力学方程和（垂向平均）热传导方程，发展了以水气温差和风速为已知量的底层温度二维数值预报模式。该模式避开了海面热量和动量输入在垂直水柱中分配的复杂物理过程而直接报出底层水温场，具有较好的实用性；此外，从试报结果看，效果令人满意。