Structure and Inter-Annual Variability of the Freshened Surface Layer in the Laptev and East-Siberian Seas During Ice-Free Periods

This work is focused on the structure and inter-annual variability of the freshened surface layer (FSL) in the Laptev and East-Siberian seas during ice-free periods. This layer is formed mainly by deltaic rivers among which the Lena River contributes about two thirds of the inflowing freshwater volume. Based on in situ measurements, we show that the area of this FSL during certain years is much greater than the area of FSL in the neighboring Kara Sea, while the total annual freshwater discharge to the Laptev and East-Siberian seas is 1.5 times less than to the Kara Sea (mainly from the estuaries of the Ob and Yenisei rivers). This feature is caused by differences in morphology of the estuaries and deltas. Shallow and narrow channels of the Lena Delta are limitedly affected by sea water. As a result, undiluted Lena discharge inflows to sea from multiple channels and forms relatively shallow plume, as compared to the Ob-Yenisei plume, which mixes with subjacent saline sea water in deep and wide estuaries. Due to small vertical extents of FSL in the Laptev and East-Siberian seas, wind conditions strongly affect its spreading and determine its significant inter-annual variability, as compared to relatively stable FSL in the Kara Sea. During years with prevailing western and northern winds, FSL is localized in the southern parts of the Laptev and East-Siberian seas due to southward Ekman transport, meridional extent (<250 km) and area (∼250,000 km2) of FSL are relatively small. During years with strong eastern winds FSL spreads northward over large area (up to 500,000 km2), its meridional extent increases up to 500–700 km. At the same time, area and position of FSL do not show any dependence on significant variability of the annual river discharge volume and ice coverage during warm season.

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Structure of the freshened surface layer in the Eastern Arctic during ice-free periods

10.5194/egusphere-egu21-255 ◽

2021 ◽

Author(s):

Alexander Osadchiev ◽

Dmitry Frey

Keyword(s):

Surface Layer ◽

Sea Water ◽

Discharge Rate ◽

World Ocean ◽

Kara Sea ◽

Surface Layers ◽

Narrow Channels ◽

Lena River ◽

Annual Variability ◽

The World

Discharges from the largest rivers of the World to coastal sea form sea-wide freshened surface layers which areas have order of hundred thousands of square kilometers. Large freshened surface layers (which are among the largest in the World Ocean) are located in the Kara, Laptev, and East-Siberian seas in the Eastern Arctic. This work is focused on the structure and inter-annual variability of these freshened water masses during ice-free periods. The freshened surface layer in the Laptev and East-Siberian seas is formed mainly by deltaic rives among which the Lena River contributes about two thirds of the inflowing freshwater volume. Based on in situ measurements, we show that the area of this freshened surface layer is much greater than the area of the freshened surface layer in the neighboring Kara Sea, while the total annual freshwater discharge to the Laptev and East-Siberian seas is 1.5 times less than to the Kara Sea (mainly from the estuaries of the Ob and Yenisei rivers). This feature is caused by differences in morphology of the estuaries and deltas. Shallow and narrow channels of the Lena Delta are limitedly affected by sea water. As a result, undiluted Lena discharge inflows to sea from multiple channels and forms relatively shallow plume, as compared to the Ob-Yenisei plumes which mix with subjacent saline sea water in deep and wide estuaries. The shallow Lena plume spreads over wide area (up to 500 000 km2) in the Laptev and East-Siberian seas during and shortly after freshet period in summer and then transforms to the Laptev/East-Siberian ROFI in autumn. Area and position of the relatively shallow freshened surface layer in the Laptev and East-Siberian seas have large inter-annual variability governed by local wind forcing conditions, however, do not show any dependence on significant variability of the annual volume of discharge rate from the Lena River. The deep freshened surface layer in the Kara Sea also has distinct seasonal varability of area and position, however, is stable on inter-annual time scale.

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Hydrology and circulation in the North Aegean (eastern Mediterranean) throughout 1997 and 1998

Mediterranean Marine Science ◽

10.12681/mms.254 ◽

2002 ◽

Vol 3 (1) ◽

pp. 5 ◽

Cited By ~ 87

Author(s):

V. ZERVAKIS ◽

D. GEORGOPOULOS

Keyword(s):

Surface Layer ◽

Black Sea ◽

Sea Water ◽

Saline Water ◽

Eastern Mediterranean ◽

Late Summer ◽

Cyclonic Circulation ◽

The Black Sea ◽

The North ◽

North Aegean

The combination of two research projects offered us the opportunity to perform a comprehensive study of the seasonal evolution of the hydrological structure and the circulation of the North Aegean Sea, at the northern extremes of the eastern Mediterranean. The combination of brackish water inflow from the Dardanelles and the sea-bottom relief dictate the significant differences between the North and South Aegean water columns. The relatively warm and highly saline South Aegean waters enter the North Aegean through the dominant cyclonic circulation of the basin. In the North Aegean, three layers of distinct water masses of very different properties are observed: The 20-50 m thick surface layer is occupied mainly by Black Sea Water, modified on its way through the Bosphorus, the Sea of Marmara and the Dardanelles. Below the surface layer there is warm and highly saline water originating in the South Aegean and the Levantine, extending down to 350-400 m depth. Below this layer, the deeper-than-400 m basins of the North Aegean contain locally formed, very dense water with different θ /S characteristics at each subbasin. The circulation is characterised by a series of permanent, semi-permanent and transient mesoscale features, overlaid on the general slow cyclonic circulation of the Aegean. The mesoscale activity, while not necessarily important in enhancing isopycnal mixing in the region, in combination with the very high stratification of the upper layers, however, increases the residence time of the water of the upper layers in the general area of the North Aegean. As a result, water having out-flowed from the Black Sea in the winter, forms a separate distinct layer in the region in spring (lying between “younger” BSW and the Levantine origin water), and is still traceable in the water column in late summer.

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Lena River Delta formation during the Holocene

Biogeosciences Discussions ◽

10.5194/bgd-11-4085-2014 ◽

2014 ◽

Vol 11 (3) ◽

pp. 4085-4122 ◽

Cited By ~ 1

Author(s):

D. Bolshiyanov ◽

A. Makarov ◽

L. Savelieva

Keyword(s):

Sea Water ◽

River Delta ◽

The Arctic ◽

Laptev Sea ◽

Lena River ◽

Sea Levels ◽

Marine Terraces ◽

Delta Formation ◽

Carbon Reservoir ◽

Lena River Delta

Abstract. The Lena River Delta, the largest delta of the Arctic Ocean, differs from other deltas because it consists mainly of organomineral sediments, commonly called peat, that contain a huge organic carbon reservoir. The analysis of Delta sediment radiocarbon ages showed that they could not have formed as peat during floodplain bogging, but accumulated when Laptev Sea water level was high and green mosses and sedges grew and were deposited on the surface of flooded marshes. The Lena River Delta formed as organomineral masses and layered sediments accumulated during transgressive phases when sea level rose. In regressive phases, the islands composed of these sediments and other, more ancient islands were eroded. Each new sea transgression led to further accumulation of layered sediments. As a result of alternating transgressive and regressive phases the first alluvial-marine terrace formed, consisting of geological bodies of different ages. Determining the formation age of different areas of the first terrace and other marine terraces on the coast allowed the periods of increasing (8–6 Ka, 4.5–4 Ka, 2.5–1.5 Ka, 0.4–0.2 Ka) and decreasing (5 Ka, 3 Ka, 0.5 Ka) Laptev Sea levels to be distinguished in the Lena Delta area.

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Density and Absolute Salinity of the Baltic Sea 2006–2009

Ocean Science Discussions ◽

10.5194/osd-6-1757-2009 ◽

2009 ◽

Vol 6 (2) ◽

pp. 1757-1817 ◽

Cited By ~ 4

Author(s):

R. Feistel ◽

S. Weinreben ◽

H. Wolf ◽

S. Seitz ◽

P. Spitzer ◽

...

Keyword(s):

Equation Of State ◽

Baltic Sea ◽

Fresh Water ◽

Decadal Variability ◽

Sea Water ◽

Large Area ◽

The Baltic Sea ◽

Sulphate Content ◽

Density Anomaly ◽

The Baltic

Abstract. The brackish water of the Baltic Sea is a mixture of ocean water from the Atlantic/North Sea with fresh water from various rivers draining a large area of lowlands and mountain ranges. The evaporation-precipitation balance results in an additional but minor excess of fresh water. The rivers carry different loads of salts washed out of the ground, in particular calcium carbonate, which cause a composition anomaly of the salt dissolved in the Baltic Sea in comparison to Standard Seawater. Directly measured seawater density shows a related anomaly when compared to the density computed from the equation of state as a function of Practical Salinity, temperature and pressure. Samples collected from different regions of the Baltic Sea during 2006–2009 were analysed for their density anomaly. The results obtained for the river load deviate significantly from similar measurements carried out forty years ago; the reasons for this decadal variability are not yet fully understood. An empirical formula is derived which estimates Absolute from Practical Salinity of Baltic Sea water, to be used in conjunction with the new Thermodynamic Equation of Seawater 2010 (TEOS-10), endorsed by IOC/UNESCO in June 2009 as the substitute for the 1980 International Equation of State, EOS-80. Our routine measurements of the samples were accompanied by studies of additional selected properties which are reported here: conductivity, density, chloride, bromide and sulphate content, total CO2 and alkalinity.

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SEASONAL PATTERN OF WIND INDUCED UPWELLING OVER JAVA-BALI SEA WATERS AND SURROUNDING AREA

International Journal of Remote Sensing and Earth Sciences (IJReSES) ◽

10.30536/j.ijreses.2008.v5.a1228 ◽

2010 ◽

Vol 5 (1) ◽

Author(s):

Siswanto ◽

Suratno

Keyword(s):

Wind Stress ◽

Coastal Upwelling ◽

Sea Water ◽

Mixed Layer Depth ◽

Surface Wind ◽

Ekman Transport ◽

Monsoon Circulation ◽

Wide Field ◽

Surrounding Area ◽

Noaa Avhrr

The influence of monsoonal wind to coastal upwelling mechanism which is generated by Ekman transport was studied here by analyzing wind stress curl (WSC) distribution over Java-Bali Sea waters and its surrounding area. Surface wind data were used as input data to calculate curl of wind stress in barotropic model. Confirmation with Corioli effect in the Southern Hemisphere, it could be known that negative curl value has relation with vertical motion of sea water as resulted by Ekman transport. Result of analysis showed that negative curl near coast over Java Sea which is stretching to Lombok Sea occurred in December to April when westerly wind of the North West Monsoon actives. It can be guidance and related with season of coastal upwelling in the region. Reversal condition, the occurrance of coastal upwelling in the south coast of JAva island related with the negative value of WSC that occurs since easterlies wind take place in May to August as a part of South East Monsoon episode. Generally, upwelling occurrance in the field of study is a response to the Monsoon circulation. This study with related data such as sea surface temperature, chlorophyll concetration and mixed layer depth that derived from satellite imaging data National Oceanic and Atmospheric Administration Advanced Very High Resolution Radiometer (NOAA-AVHRR), Aqua/Modis and sea viewing Wide Field-of-view Sensor(Sea WiFS) shows as magnificent confirmation pattern. So applying WSC to recoqnize upwelling zone is alternatively way as climatic approach to maps potential fertilizing of sea water in maritime-continent Indonesia. Key words: coastal upwelling, Ekman transport, Java-Bali Sea, Monsoon circulation, upwelling.

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Estimation of the seasonal input of freshwater in the Kara sea surface layer using hydrochemical proxies

10.5194/egusphere-egu21-14260 ◽

2021 ◽

Author(s):

Uliana Kazakova ◽

Alexander Polukhin

Keyword(s):

Surface Layer ◽

Coastal Zone ◽

Dissolved Inorganic Carbon ◽

Major Ions ◽

Kara Sea ◽

Total Alkalinity ◽

Shirshov Institute ◽

Arctic Water ◽

Total Contribution ◽

Continental Runoff

The Kara Sea receives about 55 % of the total continental runoff to the Siberian Arctic. Water of the Yenisei and Ob Rivers with low salinity (mineralization), flowing into the sea, forms a surface desalinated layer. The desalinated layer spreads over the sea area under the influence of hydrological and meteorological factors. Meltwater generated by the melting of marine and riverine ice and precipitation contribute to the formation of a surface desalinated layer along with continental runoff.Determining the amount of fresh water is not accurate enough if only the salinity of surface water is considered. It is possible to identify riverine water and meltwater using hydrochemical proxies. The ratio of the major ions in seawater differs from that in riverine and meltwater. River waters are characterized by an increased content of silicate and reduced values of total alkalinity. At the same time, it is possible to identify the waters of the Ob and Yenisei Rivers by the estimated values of the total alkalinity and dissolved inorganic carbon obtained during the research expeditions to the Kara sea from 1993 to 2020.The calculation of the parts of waters of different origin is done as a result of solving a system of equations. It includes the salinity and alkalinity values of the observed surface waters and those presumably involved in the mixing process. The salinity and alkalinity values of meltwater are taken as 0 and 134 &#181;M respectively.The total contribution of the Ob and Yenisei runoff ranges from 20 to 90% as it approaches the estuarine areas. The correlation coefficient between the proportion of river water and the salinity of the surface layer is quite high, it is equal to -0.9. This characterizes the inverse linear relationship. The separate contribution of the waters of the Yenisei differs from the contribution of the waters of the Ob, which is related to the hydrological conditions of the rivers.The contribution of meltwater to the formation of the surface layer of the Kara Sea did not exceed 20%, with the exception of the coastal zone of the Novaya Zemlya. In this coastal zone, meltwater provides the greatest contribution compared to the other sources, which is associated with glacial runoff.The work is implemented in the framework of the state assignment of the Shirshov Institute of Oceanology RAS (theme No. 0149-2019-0008), with the support of the Russian Scientific Foundation (project &#8470; 19-17-00196) and the grant of President of Russian Federation &#8470; MK-860.2020.5.

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Radionuclides Distribution and its Sorption Behavior in the Surface Layer of the Kara Sea Bottom Sediments

Geochemistry International ◽

10.1134/s0016702919110041 ◽

2019 ◽

Vol 57 (11) ◽

pp. 1213-1220

Author(s):

N. V. Kuzmenkova ◽

V. V. Krupskaya ◽

E. V. Duriagina ◽

I. N. Semenkov ◽

S. E. Vinokurov

Keyword(s):

Surface Layer ◽

Bottom Sediments ◽

Kara Sea ◽

Sorption Behavior ◽

Sea Bottom

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Density and Absolute Salinity of the Baltic Sea 2006–2009

Ocean Science ◽

10.5194/os-6-3-2010 ◽

2010 ◽

Vol 6 (1) ◽

pp. 3-24 ◽

Cited By ~ 82

Author(s):

R. Feistel ◽

S. Weinreben ◽

H. Wolf ◽

S. Seitz ◽

P. Spitzer ◽

...

Keyword(s):

Equation Of State ◽

Baltic Sea ◽

Fresh Water ◽

Decadal Variability ◽

Sea Water ◽

Large Area ◽

The Baltic Sea ◽

Sulphate Content ◽

Density Anomaly ◽

The Baltic

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Content of technogenic radionuclides in water, bottom sediments and benthos of the Kara sea and shallow bays of the Novaya zemlya archipelago

Геохимия ◽

10.31857/s0016-752564121261-1268 ◽

2019 ◽

Vol 64 (12) ◽

pp. 1261-1268

Author(s):

T. A. Goryachenkova ◽

A. P. Borisov ◽

G. Yu. Solov`eva ◽

E. A. Lavrinovich ◽

I. E. Kazinskaya ◽

...

Keyword(s):

Detection Limit ◽

Bottom Sediments ◽

Sea Water ◽

Global Fallout ◽

Kara Sea ◽

Radioactive Cesium ◽

Novaya Zemlya Archipelago ◽

Novaya Zemlya ◽

Open Sea ◽

Order Of Magnitude

During the expedition on the Akademik Mstislav Keldysh research vessel in 2016 year it was established that the content of radioactive cesium in the sea water of the Novaya Zemlya archipelago bays and open sea are at a level corresponding to the global fallout (1 Bq /m3). Plutonium content in water is slightly higher .The activity of neptunium in water is an order of magnitude higher than the activity of plutonium (0.761.89 Bq/m3), although its content in global fallout is almost two orders of magnitude lower than the plutonium content. The plutonium content in the bottom sediments of the Kara Sea is 0.23.8 Bq/kg. The content of radioactive cesium is as high as possible in the mouth of the Yenisei River (up to 21 Bq/kg) Analysis of benthic samples showed that the content of radioactive cesium and plutonium in samples taken in the bays of the Novaya Zemlya archipelago is below the detection limit. The neptunium content in the benthos samples is above the detection limit and amounts to 180 Bq/kg wet weight. It was showed that the content of neptunium in benthos is one of the indicators of radioactive contamination of the marine environment.

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Dissolved Oxygen and Apparent Oxygen Utilization in Lembeh Strait Waters, North Sulawesi

JURNAL ILMIAH PLATAX ◽

10.35800/jip.6.1.2018.17972 ◽

2017 ◽

Vol 6 (1) ◽

pp. 54

Author(s):

Simon I Patty

Keyword(s):

Surface Layer ◽

Dissolved Oxygen ◽

Sea Water ◽

Negative Impact ◽

Quality Standards ◽

Water Quality Standards ◽

Oxygen Utilization ◽

North Sulawesi ◽

Lembeh Strait ◽

Apparent Oxygen Utilization

The observation of dissolved oxygen level and Apparent Oxygen Utilization (AOU) in Lembeh Strait Waters was conducted in January, February, June and July 2016. The objective of this research is to know the condition of dissolved oxygen and Apparent Oxygen Utilization (AOU). The results of the analysis showed that dissolved oxygen levels in the surface layer and near the bottom ranged from 6.00-6.56 mg/l and 5.59-6.17 mg/l. Based on the values of temperature and salinity obtained from this study, solubility, oxygen saturation degree and AOU value at the surface layer were calculated. In the surface layer the AOU values are positive, ranging from 0.10-0.72 mg/l, while near the bottom, negative and positive AOU values were balanced, ranging from -0.23-0.42 mg/l. The concentration of dissolved oxygen in the Lembeh Strait waters has not shown negative impact on the aquatic environment and is still in accordance with sea water quality standards for marine biota.Keywords: Dissolved oxygen, apparent oxygen utilization (AOU), Lembeh Strait. ABSTRAK Pengamatan kadar oksigen terlarut dan Apparent Oxygen Utilization (AOU) di Perairan Selat Lembeh dilaksanakan pada bulan Januari, Februari, Juni dan Juli 2016. Penelitian ini bertujuan untuk mengetahui kondisi oksigen terlarut dan Apparent Oxygen Utilization (AOU). Hasil analisa menunjukkan bahwa kadar oksigen terlarut di lapisan permukaan dan dekat dasar berkisar antara 6,00-6,56 mg/l dan 5,59-6,17 mg/l. Berdasarkan nilai suhu dan salinitas yang diperoleh dari penelitian ini telah dihitung daya larut, derajat kejenuhan oksigen dan nilai AOU pada lapisan permukaan. Di lapisan permukaan nilai AOU semuanya positip berkisar antara 0,10-0,72 mg/l dan di dekat dasar nilai AOU negatip dan positip berimbang, berkisar antara -0,23-0,42 mg/l. Konsentrasi oksigen terlarut di perairan Selat Lembeh belum menunjukkan dampak negatip terhadap lingkungan perairan dan masih sesuai dengan baku mutu air laut untuk biota laut. Kata Kunci: Oksigen terlarut, apparent oxygen utilization (AOU), Selat Lembeh.

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