Vol 56, No 1 (2016)

The role of extreme surface turbulent fluxes in total oceanic heat loss in the North Atlantic is studied. The atmospheric circulation patterns enhancing ocean–atmosphere heat flux in regions with significant contributions of the extreme heat fluxes (up to 60% of the net heat loss) are analyzed. It is shown that extreme heat fluxes in the Gulf Stream and the Greenland and Labrador Seas occur in zones with maximal air pressure gradients, i.e., in cyclone–anticyclone interaction zones.

The impact of spatiotemporal variability of the ice-covered area in the Arctic on the value and interannual dynamics of turbulent heat fluxes on the ocean–atmosphere border is considered. An expected inverse dependence of the heat fluxes integrated over the Arctic area and the area of ice is not detected. The largest interannual oscillations of heat fluxes from the ocean to the atmosphere are timed to the varying position of the ice edge and, to a lesser extent, are connected with total area of ice. The role of the marginal ice zone in oceanic heat transfer is analyzed. In particular, it is shown that while moving along the marginal zone from the ice-free surface to the surface with an ice concentration of 0.8, latent and sensible heat fluxes are reduced by a factor of 2.5–3.

The upwelling of deep water associated with the influence of cyclonic wind curl and the difference in the buoyancy of the inflows in the lower and upper water layers is observed in the central part of the Black Sea. The resulting vertical water motions contribute to the transport of ammonium to the upper boundary of the anaerobic zone. In the suboxic zone, ammonium is converted to nitrate via nitrite as a result of the nitrification, and thus it can supply the nitrocline in the water basin. Within the framework of this paper we discuss the effectiveness of this mechanism on the basis of the numerical simulation. The calculations were performed using a one-dimensional physical-biogeochemical model for the upper 600-m sea water layer, which takes into account seasonal variations in atmospheric parameters and vertical motions. The model describes the biological and redox processes in the suboxic zone. We have estimated the contribution of different constituents into the balance of nitrogen compounds in the euphotic water layer. It is shown that ammonium nitrogen coming from the deep water due to vertical water motion plays a significant role in maintaining the balance of nitrates in the central part of the Black Sea.

The spatial and temporal variability of the concentration of suspended matter in the surface layer of the southeastern Baltic is analyzed using data from the satellite scanner MODIS-Aqua. The concentration of suspended matter was calculated by a regional algorithm developed on the basis of field data in the given region. The mean monthly distributions of the concentration of suspended matter from March to September 2003–2014 were calculated. The role of contributing factors is analyzed by using the data of the satellite scanner Landsat-8, with a spatial resolution of 30 m. Along with the whole area of studies, the seasonal and interannual variability of the concentration of suspended matter in different regions is considered. No meaningful trend for the average concentration of suspended matter over the considered period is shown.

The concentrations of suspended particulate matter (SPM) and particulate forms of the organic compounds (hydrocarbons, lipids, and chlorophyll a) were determined in the surface water layers of the Atlantic and Southern oceans during February to May of 2012 and 2014. It was found that the distribution of concentrations of the studied components is mainly affected by the location of frontal zones. When ice cover forms in the Southern Ocean, the changes in water temperature and phytoplankton development at the ice–water interface result in an increase of the concentrations of SPM, chlorophyll a, and, to a lesser extent, of lipids and hydrocarbons in the surface water layer. The occasional sharp increase of hydrocarbon concentrations caused by anthropogenic pollution was registered at local parts of water areas in the east of the Atlantic Ocean, as well as in the North and Baltic seas.

The content of technogenic pollutants in the coastal zone of the northeastern part of the Black Sea was evaluated. The quantitative evaluation of the level of technogenic load on the waters of Gelendzhik and Golubaya (Rybatskaya) bays was performed. A list of pollutants exceeding MPC standards was compiled.

Research was implemented from September 15 through October 4, 2011 in the Kara Sea along transects located southeastwards Novaya Zemlya, in the St. Anna Trough, the Yenisei River estuary, and the adjacent shelf. The concentration of chlorophyll a was the highest in the photic zone (0.05–2.30 mg/m³, on average, 0.80 ± 0.37 mg/m³). The maximal concentration of Chl a at most of the stations located in the water layer of 7–30 m. Integral primary production in the water column varied from 3.0 to 151.0 mg C/m² per day, on average, 37.2 ± 36.6 mg C/m² per day. The maximal rate of primary production at most of the stations has been observed for the surface layer of the water column. Within the upper mixed water layer, relative primary production was from 31 to 100% (on average, 77 ± 20%). The most productive zone was the waters along Yenisei transect. In the estuary and at the adjacent shelf, primary production was 50 mg C/m² per day, exceeding the range observed for other areas by 1.5–2.0 times. The concentrations of silica and nitrogen together with light regime and water temperature were the major limiting factors affecting the primary production rate in the Kara Sea in autumn.

The phytoplankton community and its distribution were investigated in the eastern branch of the St. Anna Trough and over the adjacent Kara Sea shelf in September 2011 and in August 2014. The spatial and seasonal differences in the phytoplankton structure were analyzed in connection with ice melting and changes in the temperature, salinity, and biogenic regime. Four 4 zones were defined: the Kara Sea shelf, the upper part of the St. Anna Trough slope, the lower part of the St. Anna Trough slope, and its deep part. It was shown that over the Kara Sea shelf where riverine runoff influence was observed, the phytoplankton community differs from the community of the St. Anna Trough in both investigated periods: in September and August. Rearrangement of the phytoplankton community was observed in the frontal zone associated with the upper part of the slope in September of 2011. The main features of this rearrangement were a change in dominant species composition and a 1.5–2-fold increase in the number and biomass of algae. Over the lower part of the slope and deep area of the St. Anna Trough in August 2014 and September 2011, the phytoplankton community was at different successive stages: in August, at the late spring and summer stage, and in September, at the summer–autumn stage.

This paper presents reconstructions of ice sheet boundaries, lacustrine and marine paleobasins, as well as the connections of the Barents and Baltic seas with the North Atlantic from the Last Glacial Maximum to the Holocene. The reconstructions are based on original and published data obtained from the northern and western parts of the Barents Sea and Baltic depressions with account for the available regional schematic maps of deglaciation. The early deglaciation of the Scandinavian–Barents ice sheet culminated with the Bølling-Allerød interstadial (14.5–12.9 cal ka BP), which was characterized by a more vigorous Atlantic meridional overturning circulation (AMOC) and a corresponding increase in surface Atlantic water inflow into the Barents Sea through deep troughs. The Baltic Ice Lake (BIL) remained a dammed-up isolated basin during deglaciation from 16.0 to 11.7 cal ka BP. In the Younger Dryas (YD), the lake drained into the North Sea and was replaced by a brackish Yoldia Sea (YS) at the beginning of the Holocene (Preboreal, 11.7–10.7 cal ka BP), due to a limited connection between two basins through the Närke Strait. In the Barents Sea, the next increase in the Atlantic water influx into the deep basins corresponded to terminal YD and Preboreal events with a culmination in the Early Holocene. The Yoldia Sea became a lake again during the next stage, the Ancylus (~10.7–8.8 cal ka BP). Atlantic water inflow both into the Barents and Baltic seas varied during the Holocene, with a maximum contribution in the Early Holocene, when the Littorina Sea (LS, 8–4 cal ka BP) connection with the North Sea via the Danish Straits was formed to replace the Ancylus Lake. The recent, post-Littorina stage (PS, the last 4 cal ka) of the Baltic Sea evolution began in the Late Holocene.

Pelagic sediments from three cores in the northern tropical Pacific zone (the northeast basin) have been analyzed for particle size and composition, as well as for number, mass and the distribution of protosyngenetic authigenic manganese micronodules (MN) in them. The sequences are represented by Quaternary carbonate-free clayey–radiolarian, radiolarian–clayey oozes, miopelagic clays, sometimes enriched in radiolarians, pre-Pleistocene miopelagic and eupelagic clays, zeolite–clayey sediments, and zeolitites. Based on factual data (volume of wet sediment, weight of dry sediment and micronodules, their number and proportions of four fractions, the contribution of MN in sediment, and others), the values of different parameters were calculated. The obtained parameters are statistically similar, which allowed us to reveal background and anomalous horizons of sediments and to assume their sedimentation conditions. Similar values of Р_MN/N_MN, Р_fr > 0.05 mm, Р_MN/Р_sed and the mass of micronodules suggest that precisely these parameters reflect the main variations in conditions of pelagic sedimentation.

This paper presents the description of a monitoring system based on drifters equipped with GPSreceiver and cellular GSM. The system provides data about currents with a temporal and spatial resolution of 5–10 minutes and 100–200 m. The movement of the drifter can be observed in real time. Several experiments were conducted on the Black Sea shelf for identification of the advantages of the monitoring system. The results of experiments include a comparison of the drifter trajectories with bottom-tracked ADCP and towed ADCP data.