scholarly journals Reconstruction of Atlantic water variability during the Holocene in the western Barents Sea

2014 ◽  
Vol 10 (1) ◽  
pp. 51-62 ◽  
Author(s):  
D. E. Groot ◽  
S. Aagaard-Sørensen ◽  
K. Husum
Keyword(s):  
Barents Sea ◽  
Transfer Functions ◽  
Distribution Patterns ◽  
Atlantic Water ◽  
The Arctic ◽  
Arctic Water ◽  
The Holocene ◽  
Fine Grained ◽  
The Core ◽  
Local Shift

Abstract. The gravity core JM09-KA11-GC from 345 m water depth on the western Barents Sea margin was investigated for down-core distribution patterns of benthic Foraminifera, stable isotopes, and sedimentological parameters in order to reconstruct the flow of Atlantic water during the Holocene. The core site is located below the Atlantic water masses flowing into the Arctic Ocean and close to the Arctic front. The results show continuous presence of Atlantic water at the margin throughout the Holocene. During the early Holocene, (11 500–9800 cal yr BP), bottom water temperatures as calculated by transfer functions rose by 1.5 °C, likely due to the increased inflow of Atlantic water, although sea ice was still present at this time. The transition to the mid-Holocene is characterized by a local shift in current regime, resulting in a ceased supply of fine-grained material to the core location. Throughout the mid-Holocene the δ18O values indicate a slight cooling, thereby following changes in insolation. In the last 1500 yr, inflow of Atlantic water increased but was interrupted by periods of increased influence of Arctic water causing periodically colder and more unstable conditions.

scholarly journals Reconstruction of Atlantic Water variability during the Holocene in the western Barents Sea

2013 ◽  
Vol 9 (4) ◽  
pp. 4293-4322 ◽  
Author(s):  
D. E. Groot ◽  
S. Aagaard-Sørensen ◽  
K. Husum
Keyword(s):  
Barents Sea ◽  
Distribution Patterns ◽  
Atlantic Water ◽  
The Arctic ◽  
Arctic Water ◽  
The Holocene ◽  
Fine Grained ◽  
The Core ◽  
Continuous Presence ◽  
Local Shift

Abstract. The gravity core JM09-KA11-GC from 345 m water depth on the western Barents Sea margin was investigated for distribution patterns of benthic foraminifera, stable isotopes, and sedimentological parameters to reconstruct the flow of Atlantic Water during the Holocene. The core site is located below the Atlantic water masses flowing into the Arctic Ocean and close to the Arctic Front. The results show continuous presence of Atlantic Water at the margin throughout the Holocene. During the Early Holocene, (11 700–9400 cal yr BP), bottom water temperatures rose by 2.5 °C due to the increased influence of Atlantic Water, although sea-ice was still present at this time. The transition to the Mid Holocene is characterized by a local shift in current regime, resulting in a ceased supply of fine-grained material to the core location. Throughout the Mid Holocene the δ18O values indicate a slight cooling, thereby following changes in insolation. In the last 1500 yr, inflow of Atlantic Water increased but was interrupted by periods of increased influence of Arctic Water causing periodically colder and more unstable conditions.

scholarly journals HEAVY METALS IN ZOOPLANKTON ORGANISMS OF THE BARENTS SEA

2019 ◽  
Vol 47 (4) ◽  
pp. 62-75
Author(s):  
L. L. Demina ◽  
A. S. Solomatina ◽  
G. A. Abyzova
Keyword(s):  
Heavy Metals ◽  
Barents Sea ◽  
Water Mass ◽  
Atlantic Water ◽  
Polar Front ◽  
The Arctic ◽  
Phytoplankton Production ◽  
Arctic Water ◽  
The Barents Sea ◽  
Geochemical Parameters

Zooplankton plays a Central role in the transfer of matter and energy from primary producers to high trophic organisms, and zooplankton serves as an essential component of sedimentary material that supplies organic matter to the bottom of marine basins. The paper presents new data on the distribution of a number of heavy metals (Cd, Co, Cr, Cu, Mo, Ni, Pb) and As in the Calanus zooplankton collected in July–August 2017 in the North-Eastern, Eastern and Central parts of the Barents Sea. It is shown that the spatial distribution of metals in zooplankton organisms is influenced by both biotic ecosystem factors associated with bioproductivity and hydrological and geochemical parameters of the habitat (North Polar Front). In the zooplankton of the Arctic water mass to the South-East of Franz Josef Land, there was an increased content of essential heavy metals Cu, Zn and Cr in comparison with the coastal and Atlantic water masses. Zooplankton from the Central part of the sea (Atlantic water mass), where phytoplankton production is reduced, is characterized by the lowest concentrations of most elements (Ni, Cu, Zn, As and Pb). The highest concentrations were found for both essential heavy metals (Zn and Cu) and toxic metalloid As, which may indicate non-selective bioaccumulation of trace elements by copepods.

scholarly journals The Barents Sea frontal zones and water masses variability (1980–2011)

Ocean Science ◽  
2016 ◽  
Vol 12 (1) ◽  
pp. 169-184 ◽  
Author(s):  
L. Oziel ◽  
J. Sirven ◽  
J.-C. Gascard
Keyword(s):  
Interannual Variability ◽  
Barents Sea ◽  
Sea Water ◽  
Atlantic Water ◽  
Polar Front ◽  
Water Masses ◽  
The Arctic ◽  
Arctic Water ◽  
The Barents Sea ◽  
Frontal Zones

Abstract. The polar front separates the warm and saline Atlantic Water entering the southern Barents Sea from the cold and fresh Arctic Water located in the north. These water masses can mix together (mainly in the center of the Barents Sea), be cooled by the atmosphere and receive salt because of brine release; these processes generate dense water in winter, which then cascades into the Arctic Ocean to form the Arctic Intermediate Water. To study the interannual variability and evolution of the frontal zones and the corresponding variations of the water masses, we have merged data from the International Council for the Exploration of the Sea and the Arctic and Antarctic Research Institute and have built a new database, which covers the 1980–2011 period. The summer data were interpolated on a regular grid. A probability density function is used to show that the polar front splits into two branches east of 32° E where the topographic constraint weakens. Two fronts can then be identified: the Northern Front is associated with strong salinity gradients and the Southern Front with temperature gradients. Both fronts enclose the denser Barents Sea Water. The interannual variability of the water masses is apparent in the observed data and is linked to that of the ice cover. The frontal zones variability is found by using data from a general circulation model. The link with the atmospheric variability, represented here by the Arctic Oscillation, is not clear. However, model results suggest that such a link could be validated if winter data were taken into account. A strong trend appears: the Atlantic Water (Arctic Water) occupies a larger (smaller) volume of the Barents Sea. This trend amplifies during the last decade and the model study suggests that this could be accompanied by a northwards displacement of the Southern Front in the eastern part of the Barents Sea. The results are less clear for the Northern Front. The observations show that the volume of the Barents Sea Water remains nearly unchanged, which suggests a northwards shift of the Northern Front to compensate for the northward shift of the Southern Front. Lastly, we noticed that the seasonal variability of the position of the front is small.

scholarly journals Contribution of Calanus species to the mesozooplankton biomass in the Barents Sea

2017 ◽  
Vol 75 (7) ◽  
pp. 2342-2354 ◽  
Author(s):  
Johanna Myrseth Aarflot ◽  
Hein Rune Skjoldal ◽  
Padmini Dalpadado ◽  
Mette Skern-Mauritzen
Keyword(s):  
Barents Sea ◽  
Zooplankton Community ◽  
Zooplankton Biomass ◽  
Calanus Finmarchicus ◽  
The Arctic ◽  
Arctic Water ◽  
Mesozooplankton Biomass ◽  
The Barents Sea ◽  
Main Driver ◽  
Calanus Species

Abstract Copepods from the genus Calanus are crucial prey for fish, seabirds and mammals in the Nordic and Barents Sea ecosystems. The objective of this study is to determine the contribution of Calanus species to the mesozooplankton biomass in the Barents Sea. We analyse an extensive dataset of Calanus finmarchicus, Calanus glacialis, and Calanus hyperboreus, collected at various research surveys over a 30-year period. Our results show that the Calanus species are a main driver of variation in the mesozooplankton biomass in the Barents Sea, and constitutes around 80% of the total. The proportion of Calanus decreases at low zooplankton biomass, possibly due to a combination of advective processes (low C. finmarchicus in winter) and size selective foraging. Though the Calanus species co-occur in most regions, C. glacialis dominates in the Arctic water masses, while C. finmarchicus dominates in Atlantic waters. The larger C. hyperboreus has considerably lower biomass in the Barents Sea than the other Calanus species. Stages CIV and CV have the largest contribution to Calanus species biomass, whereas stages CI-CIII have an overall low impact on the biomass. In the western area of the Barents Sea, we observe indications of an ongoing borealization of the zooplankton community, with a decreasing proportion of the Arctic C. glacialis over the past 20 years. Atlantic C. finmarchicus have increased during the same period.

A satellite-based Lagrangian perspective on Atlantic Water fractionation in the Nordic Seas

2020 ◽  
Author(s):  
Léon Chafik ◽  
Sara Broomé
Keyword(s):  
Arctic Ocean ◽  
Barents Sea ◽  
Bottom Topography ◽  
Atlantic Water ◽  
The Arctic ◽  
Fram Strait ◽  
Nordic Seas ◽  
The Barents Sea ◽  
The Arctic Ocean ◽  
Outer Branch

<p>The Arctic Ocean has been receiving more of the warm and saline Atlantic Water in the past decades. This water mass enters the Arctic Ocean via two Arctic gateways: the Barents Sea Opening and the Fram Strait. Here, we focus on the fractionation of Atlantic Water at these two gateways using a Lagrangian approach based on satellite-derived geostrophic velocities. Simulated particles are released at 70N at the inner and outer branch of the North Atlantic current system in the Nordic Seas. The trajectories toward the Fram Strait and Barents Sea Opening are found to be largely steered by the bottom topography and there is an indication of an anti-phase relationship in the number of particles reaching the gateways. There is, however, a significant cross-over of particles from the outer branch to the inner branch and into the Barents Sea, which is found to be related to high eddy kinetic energy between the branches. This cross-over may be important for Arctic climate variability.</p>

scholarly journals The Movement of Atlantic Water in the Arctic Ocean

ARCTIC ◽  
1963 ◽  
Vol 16 (1) ◽  
pp. 8 ◽  
Author(s):  
L.K. Coachman ◽  
C.A. Barnes
Keyword(s):  
Arctic Ocean ◽  
Arctic Basin ◽  
Core Layer ◽  
Atlantic Water ◽  
The Arctic ◽  
The Core ◽  
The Arctic Ocean ◽  
Percentage Retention ◽  
Oceanographic Data ◽  
Vertical Eddy

Re-evaluates sixty years' oceanographic data from the Arctic Ocean, examining nearly 300 deep-water stations, and using the "core-layer" method of Wust to interpret the movement of the Atlantic layer. Stations are grouped in 16 areas and the average curve for each group plotted on a temperature-salinity diagram. Temperature and salinity changes which take place in the Atlantic water while and entity in the Arctic Basin are graphed. The temperature maximum is reduced by about 3.5 C, and the salinity at max. temperature is reduced by about 0.2 %. Superimposed on the T-S relationship is an arbitrary scale indicating percentage retention of the original characteristics. The velocity of the Atlantic layer is found (from current velocity, eddy coefficients and station data) to range 1-10 cm/sec and values of Kz (vertical eddy coefficient) generally to range 1-20 sq cm/sec. Percentage retention of characteristics from the T-S diagram is mapped to suggest a relation between the flow of Atlantic water and bathymetry, distance, time, as well as the T-S features. Assuming the velocity along the core to be 3 cm/sec, the constant vertical eddy coefficient to be 10 sq cm/sec, and with other assumptions on temperature distribution, an estimate of 8,000,000 sq cm/sec is obtained for the constant lateral eddy coefficient.

scholarly journals Influence of Atlantic inflow on the freshwater content in the upper layer of the Arctic basin

2019 ◽  
Vol 65 (4) ◽  
pp. 363-388
Author(s):  
G. V. Alekseev ◽  
A. V. Pnyushkov ◽  
A. V. Smirnov ◽  
A. E. Vyazilova ◽  
N. I. Glok
Keyword(s):  
Fresh Water ◽  
Large Scale ◽  
Barents Sea ◽  
Lower Boundary ◽  
Arctic Basin ◽  
Water Layer ◽  
Atlantic Water ◽  
Water Masses ◽  
The Arctic ◽  
The North

Inter-decadal changes in the water layer of Atlantic origin and freshwater content (FWC) in the upper 100 m layer were traced jointly to assess the influence of inflows from the Atlantic on FWC changes based on oceanographic observations in the Arctic Basin for the 1960s – 2010s. For this assessment, we used oceanographic data collected at the Arctic and Antarctic Research Institute (AARI) and the International Arctic Research Center (IARC). The AARI data for the decades of 1960s – 1990s were obtained mainly at the North Pole drifting ice camps, in high-latitude aerial surveys in the 1970s, as well as in ship-based expeditions in the 1990s. The IARC database contains oceanographic measurements acquired using modern CTD (Conductivity – Temperature – Depth) systems starting from the 2000s. For the reconstruction of decadal fields of the depths of the upper and lower 0 °С isotherms and FWC in the 0–100 m layer in the periods with a relatively small number of observations (1970s – 1990s), we used a climatic regression method based on the conservativeness of the large-scale structure of water masses in the Arctic Basin. Decadal fields with higher data coverage were built using the DIVAnd algorithm. Both methods showed almost identical results when compared.  The results demonstrated that the upper boundary of the Atlantic water (AW) layer, identified with the depth of zero isotherm, raised everywhere by several tens of meters in 1990s – 2010s, when compared to its position before the start of warming in the 1970s. The lower boundary of the AW layer, also determined by the depth of zero isotherm, became deeper. Such displacements of the layer boundaries indicate an increase in the volume of water in the Arctic Basin coming not only through the Fram Strait, but also through the Barents Sea. As a result, the balance of water masses was disturbed and its restoration had to occur due to the reduction of the volume of the upper most dynamic freshened layer. Accordingly, the content of fresh water in this layer should decrease. Our results confirmed that FWC in the 0–100 m layer has decreased to 2 m in the Eurasian part of the Arctic Basin to the west of 180° E in the 1990s. In contrast, the FWC to the east of 180° E and closer to the shores of Alaska and the Canadian archipelago has increased. These opposite tendencies have been intensified in the 2000s and the 2010s. A spatial correlation between distributions of the FWC and the positions of the upper AW boundary over different decades confirms a close relationship between both distributions. The influence of fresh water inflow is manifested as an increase in water storage in the Canadian Basin and the Beaufort Gyre in the 1990s – 2010s. The response of water temperature changes from the tropical Atlantic to the Arctic Basin was traced, suggesting not only the influence of SST at low latitudes on changes in FWC, but indicating the distant tropical impact on Arctic processes. 

scholarly journals Enhancement of the North Atlantic CO<sub>2</sub> sink by Arctic Waters

2021 ◽  
Vol 18 (5) ◽  
pp. 1689-1701
Author(s):  
Jon Olafsson ◽  
Solveig R. Olafsdottir ◽  
Taro Takahashi ◽  
Magnus Danielsen ◽  
Thorarinn S. Arnarson
Keyword(s):  
North Atlantic ◽  
Thermohaline Circulation ◽  
Atlantic Water ◽  
Water Masses ◽  
The Arctic ◽  
Arctic Water ◽  
The North ◽  
The North Atlantic ◽  
Co2 Sink ◽  
The One

Abstract. The North Atlantic north of 50∘ N is one of the most intense ocean sink areas for atmospheric CO2 considering the flux per unit area, 0.27 Pg-C yr−1, equivalent to −2.5 mol C m−2 yr−1. The northwest Atlantic Ocean is a region with high anthropogenic carbon inventories. This is on account of processes which sustain CO2 air–sea fluxes, in particular strong seasonal winds, ocean heat loss, deep convective mixing, and CO2 drawdown by primary production. The region is in the northern limb of the global thermohaline circulation, a path for the long-term deep-sea sequestration of carbon dioxide. The surface water masses in the North Atlantic are of contrasting origins and character, with the northward-flowing North Atlantic Drift, a Gulf Stream offspring, on the one hand and on the other hand the cold southward-moving low-salinity Polar and Arctic waters with signatures from Arctic freshwater sources. We have studied by observation the CO2 air–sea flux of the relevant water masses in the vicinity of Iceland in all seasons and in different years. Here we show that the highest ocean CO2 influx is to the Arctic and Polar waters, respectively, -3.8±0.4 and -4.4±0.3 mol C m−2 yr−1. These waters are CO2 undersaturated in all seasons. The Atlantic Water is a weak or neutral sink, near CO2 saturation, after poleward drift from subtropical latitudes. These characteristics of the three water masses are confirmed by data from observations covering 30 years. We relate the Polar Water and Arctic Water persistent undersaturation and CO2 influx to the excess alkalinity derived from Arctic sources. Carbonate chemistry equilibrium calculations clearly indicate that the excess alkalinity may support at least 0.058 Pg-C yr−1, a significant portion of the North Atlantic CO2 sink. The Arctic contribution to the North Atlantic CO2 sink which we reveal was previously unrecognized. However, we point out that there are gaps and conflicts in the knowledge about the Arctic alkalinity and carbonate budgets and that future trends in the North Atlantic CO2 sink are connected to developments in the rapidly warming and changing Arctic. The results we present need to be taken into consideration for the following question: will the North Atlantic continue to absorb CO2 in the future as it has in the past?

Transformation of Atlantic Water in the Barents Sea in winter: overview of “Transarctika-2019” cruise results

2020 ◽  
Author(s):  
Vladimir Ivanov ◽  
Ivan Frolov ◽  
Kirill Filchuk
Keyword(s):  
Characteristic Feature ◽  
Sea Ice ◽  
Arctic Ocean ◽  
Water Column ◽  
Barents Sea ◽  
Atlantic Water ◽  
The Arctic ◽  
The Barents Sea ◽  
Open Sea ◽  
The Arctic Ocean

&lt;p&gt;In the recent few years the topic of accelerated sea ice loss, and related changes in the vertical structure of water masses in the East-Atlantic sector of the Arctic Ocean, including the Barents Sea and the western part of the Nansen Basin, has been in the foci of multiple studies. This region even earned the name the &amp;#8220;Arctic warming hotspot&amp;#8221;, due to the extreme retreat of sea ice and clear signs of change in the vertical hydrographic structure from the Arctic type to the sub-Arctic one. A gradual increase in temperature and salinity in this area has been observed since the mid-2000s. This trend is hypothetically associated with a general decrease in the volume of sea ice in the Arctic Ocean, which leads to a decrease of ice import in the Barents Sea, salinization, weakening of density stratification, intensification of vertical mixing and an increase of heat and salt fluxes from the deep to the upper mixed layer. The result of such changes is a further reduction of sea ice, i.e. implementation of positive feedback, which is conventionally refereed as the &amp;#8220;atlantification. Due to the fact that the Barents Sea is a relatively shallow basin, the process of atlantification might develop here much faster than in the deep Nansen Basin. Thus, theoretically, the hydrographic regime in the northern part of the Barents Sea may rapidly transform to a &amp;#8220;Nordic Seas &amp;#8211; wise&amp;#8221;, a characteristic feature of which is the year-round absence of the ice cover with debatable consequences for the climate and ecosystem of the region and adjacent land areas. Due to the obvious reasons, historical observations in the Barents Sea mostly cover the summer season. Here we present a rare oceanographic data, collected during the late winter - early spring in 2019. Measurements were occupied at four sequential oceanographic surveys from the boundary between the Norwegian Sea and the Barents Sea &amp;#8211; the so called Barents Sea opening to the boundary between the Barents Sea and the Kara Sea. Completed hydrological sections allowed us to estimate the contribution of the winter processes in the Atlantic Water transformation at the end of the winter season. Characteristic feature of the observed transformation is the homogenization of the near-to-bottom part of the water column with remaining stratification in the upper part. A probable explanation of such changes is the dominance of shelf convection and cascading of dense water over the open sea convection. In this case, complete homogenization of the water column does not occur, since convection in the open sea is impeded by salinity and density stratification, which is maintained by melting of the imported sea ice in the relatively warm water. The study was supported by RFBR grant # 18-05-60083.&lt;/p&gt;

scholarly journals The Arctic Ocean Seasonal Cycles of Heat and Freshwater Fluxes: Observation-Based Inverse Estimates

2018 ◽  
Vol 48 (9) ◽  
pp. 2029-2055 ◽  
Author(s):  
Takamasa Tsubouchi ◽  
Sheldon Bacon ◽  
Yevgeny Aksenov ◽  
Alberto C. Naveira Garabato ◽  
Agnieszka Beszczynska-Möller ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Barents Sea ◽  
Numerical Models ◽  
Water Layer ◽  
Atlantic Water ◽  
Surface Fluxes ◽  
The Arctic ◽  
Bering Strait ◽  
The Arctic Ocean

AbstractThis paper presents the first estimate of the seasonal cycle of ocean and sea ice heat and freshwater (FW) fluxes around the Arctic Ocean boundary. The ocean transports are estimated primarily using 138 moored instruments deployed in September 2005–August 2006 across the four main Arctic gateways: Davis, Fram, and Bering Straits, and the Barents Sea Opening (BSO). Sea ice transports are estimated from a sea ice assimilation product. Monthly velocity fields are calculated with a box inverse model that enforces mass and salt conservation. The volume transports in the four gateways in the period (annual mean ± 1 standard deviation) are −2.1 ± 0.7 Sv in Davis Strait, −1.1 ± 1.2 Sv in Fram Strait, 2.3 ± 1.2 Sv in the BSO, and 0.7 ± 0.7 Sv in Bering Strait (1 Sv ≡ 106 m3 s−1). The resulting ocean and sea ice heat and FW fluxes are 175 ± 48 TW and 204 ± 85 mSv, respectively. These boundary fluxes accurately represent the annual means of the relevant surface fluxes. The ocean heat transport variability derives from velocity variability in the Atlantic Water layer and temperature variability in the upper part of the water column. The ocean FW transport variability is dominated by Bering Strait velocity variability. The net water mass transformation in the Arctic entails a freshening and cooling of inflowing waters by 0.62 ± 0.23 in salinity and 3.74° ± 0.76°C in temperature, respectively, and a reduction in density by 0.23 ± 0.20 kg m−3. The boundary heat and FW fluxes provide a benchmark dataset for the validation of numerical models and atmospheric reanalysis products.

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