Vol 58, No 6 (2018)

The paper proposes a new parameterization of natural dispersion of a marine oil spill due to wind-wave breakup of the oil slick and penetration of oil droplets into the water. The quantity of oil returning to the surface due to positive buoyancy in the time between wind wave overturns is estimated. The role of vertical turbulent exchange as a factor limiting oil droplet flux from the sea surface into the water column is discussed.

One the most complete megadatabases for the period of 1914–2010 is used to study the interannual dynamics of salinity and temperature of Caspian Sea waters. Periods with relatively stable sea levels but different climatic conditions are considered. Average interannual climatic salinity and temperature profiles of water and corresponding anomalies are analyzed. Quantitative and qualitative changes in the structure of seawater that took place during the 20th century are described. Schemes of water exchange between particular sea regions for different sea levels are proposed.

Based on the material obtained in the spring–summer season of 2016, the composition and quantitative distribution of phytoplankton in the Ob estuary and over the Kara Sea shelf has been estimated. The latitudinal extent of the region exceeded 5° (~560 km), encompassing areas with different river discharge impact, which formed latitudinal zoning in the distribution of hydrophysical and hydrochemical conditions. These environmental properties determined the zoning in the spatial structure of phytoplankton communities. The estuarine biotope with a salinity <1 PSU and high concentrations of nitrate, phosphate, and silica was inhabited by a freshwater phytocenosis stable in species composition with high-quantitative characteristics and dominated by Aulacoseira species. The most spatial and seasonal variability of phytoplankton is characteristic of the area of intense interaction of fresh and marine waters in the outer part of the Ob estuary and over the adjacent shallow shelf, where freshwater algae species are replaced by marine species. A sharp biotopic boundary separates the inner shallow shelf with depths of approximately 30–35 m and outer shelf of the depth from 150 to 200 m. In the area of the outer shelf the lower boundary of the euphotic zone descends to 25–35 m. At theses depths plankton algae actively vegetate, and form subsurface phytoplankton maximum under conditions of sufficient nutrient concentration.

The zooplankton community in two bays of the eastern coast of the Novaya Zemlya archipelago (Blagopoluchiya Bay and Tsivolki Bay) has been studied for the first time. Copepods of the genus Calanus—C. glacialis/finmarchicus and C. hyperboreus—dominate the zooplankton of the bays in terms of biomass (76–93%). These copepods reached the highest abundance in Blagopoluchiya Bay. The total abundance (70 000 ind./m²) and biomass (60 g/m²) of the population were many times higher than the maximum values recorded from waters of the Kara Sea shelf. The ration values for these copepods ranged from 1.5 to 20 µg C ind.^–1 day^–1 at different copepodite stages. The rate of grazing on phytoplankton biomass and production by zooplankton varied within 1.5–15.6% and from 3 to 127%, respectively. In the considered bay, the flux of organic carbon and suspended particulate matter contained in Calanus fecal pellets reached 157.5 mg C_org m^–2 day^–1 and 1574 mg m^–2 day^–1, respectively. In Tsivolki Bay, the total zooplankton biomass (6.6 g/m²) was several times lower. This has led to a decrease in its role in phytoplankton utilization (0.6–2.4% of phytoplankton biomass and 1.9–18% of phytoplankton production), as well as to a less intensive flux of suspended particulate matter (47.8 mg m^–2 day^–1) and organic carbon of copepod fecal pellets (2.6 mg C_org m^–2 day^–1) in the bay.

The bearded seal occurs in virtually all Arctic seas. During the spring (pupping and mating season), this species is characterized by high underwater acoustic activity; studies performed in the foreign countries in the 1960s showed that sexually mature males produced the signals. The present article discusses a comprehensive analysis of bearded seal acoustic signals recorded in 1984–2017 in different parts of the White Sea. The main types of signals were identified, the physical characteristics of the signals were described, and territorial and temporal variability of the signals was assessed. High overall stability was demonstrated for bearded seals’ underwater acoustic signaling system. Acoustic census methods to account for individuals present in the studied water area have been proposed based on the results.

The article discusses the results of studying the marginal filter of the Pregolya River in different seasons. Three transformation stages of dispersed sedimentary material are distinguished: gravitational, colloidal–sorption, and biogenic. Study of the chemical composition of suspended particulate matter at all marginal filter stages showed variation in the composition of suspension-forming elements, as well as strong enrichment of suspended particulate matter in a number of trace elements, which can be explained by pollution. Matrix correlation analysis of chemical element concentrations revealed strong links between elements.

Our new and previously published data on sea surface bioproductivity changes from different parts of the Pacific Ocean in the Northern Hemisphere were analyzed in relation to meridional overturning circulation during the last deglaciation. Synchronous episodes of upwelling intensification in the Eastern Equatorial Pacific and Southern Ocean cores indicate that millennial-scale sea-surface bioproductivity changes reflect climatic teleconnection between these two regions by means of “oceanic tunnelling.” In the North Pacific, postglacial bioproductivity changes are in line with climate oscillations recorded in the North Greenland Ice Core and transferred to the North Pacific via the atmospheric bridge. However, in the western Bering Sea, breakdown of stratification, CO₂ release into the atmosphere and sea-surface bioproductivity rise occurred immediately at the onset of Heinrich I (~17.5–17.0 kyr BP). This might result from upwelling of southern-sourced deep water. The upwelling has been developed in the Subarctic Pacific approximately 1000–1500 years later than in the Southern Ocean. This lag likely reflects the duration of signal transferring from the high latitudes of the Southern Hemisphere to the North Pacific.

The mean contents of elements (Fe, Mn, Zn, Pb, Cu, Cr, V, Co, Cd, Ni, As, Sc, Ga, Zr, Hf, Nb, Ta, W, Th, Mo) in the subcolloidal fraction of bottom sediments in the northern part of Amur Bay have been determined. A 5–17% increase is observed in the heavy metal content (Pb, Co, Ni, Zn, Cr, V, As) compared to the mean values for sediments directly subjected to the influence of the Razdolnaya River, which is related to flocculation and sorption on Fe and Mn oxyhydroxides. A linear dependence of heavy metal accumulation on the Fe and Mn content is established. An increase in the Cu and Mo content is revealed (by 49 and 44%, respectively), related to vital accumulation by plankton, as well as in increase in V, Cr, Co, Ni, Zn, Cd, and As (by 2–20%) in sediments subjected to anthropogenic impact.

Over the past 50 years, a number of major scientific discoveries have been made in the World Ocean. The most important of these is the discovery of hydrothermal fields on the ocean floor. In addition, a significant leap has occurred in the practical development of ocean depths in terms of prospecting and organizing the recovery of mineral and energy resources. This has become possible only through the introduction of new technical means, the main one among them being underwater vehicles. This report discusses the role of different types of apparatus at various stages of exploration, detailed studies of local ocean areas, and organization of mining and energy resources. Data on the use of different types of apparatus are given, and the effectiveness of their application for various purposes are considered.