Model estimates for the mean gas exchange between the ocean and the atmosphere under the conditions of the present-day climate and its changes expected in the 21st century

Annual mean fluxes of CO₂ and oxygen across the sea surface are estimated with the use of numerical modeling for several regions located in the Gulf Stream and Kuroshio zones. The present-day climatic conditions and the climatic conditions expected in the middle and at the end of the 21st century are considered. Specific features of gas exchange under a strong wind that are associated with gas exchange by bubbles and with changes in the air-water difference of the gas concentrations were taken into account in the calculations. The estimates obtained differ substantially from the results based on the traditional approach, which disregards the above features. A considerable increase in the absorption of CO₂ by the ocean, which is mainly caused by the continuing increase in the CO₂ concentration in the air during its small changes in the ocean, is expected in the 21st century. At the same time, no trends are revealed in the annual mean fluxes of oxygen across the ocean surface. The conclusion is made that, in calculations of CO₂ absorption by the world ocean, it is necessary to take into account both specific features of gas transfer under a strong wind and an increase in the atmospheric concentration of CO₂.     

Basement structure and sedimentary cover seismostratigraphy in the northern part of the Japan Basin in the region of the Tarasov Rise (Sea of Japan)

The results of continuous seismic profiling thermodynamics performed in the northern part of the Japan Basin in the region of the Tarasov Rise and the data of a micropaleontological examination of the diatom remains encountered in the sediment samples from the rise and continental slope are presented. In the area studied, the topography of the acoustic basement features a vast rise (plateau) buried under the sedimentary cover outlined by the depth contour 5.8 s. The plateau has a relatively smooth top surface crossed by a series of rises of the acoustic basement. The two largest rises are represented by the ridges of the Tarasov Rise. The plateau is separated from the continental slope by a depression in the acoustic basement with a depth up to 6.8 s. From the end of the Middle Miocene up to the beginning of the Paleocene, the region of the plateau represented an area of active volcanism; it coincided in time with the stage of subsidence of the floor of the acoustic basement depression. At the end of the Late Miocene, the ridges of the Tarasov Rise started to sink. In the Pliocene, this process accelerated, and, at the beginning of the Pleistocene, it stopped. In the Middle Miocene-Early Pleistocene time, the portion of the continental slope adjacent to the plateau remained stable and suffered no significant vertical movements.     

Major variability modes and wind patterns over the Sea of Japan and adjacent areas

The expansion of wind fields observed at fixed times (four times daily) in complex empirical orthogonal functions is performed for the Japan Sea area (34°–53° N, 127°–143° E). The wind fields are taken from the 1998–2004 NCEP/NCAR Reanalysis data with better spatial resolution (1° × 1°) than the standard product, which are publicly available on the Internet. Major modes of wind variability in the Japan Sea area are identified. The modes determine a general direction of air-mass transport throughout a year, zonal and meridional modulation, and a cyclonic and an anticyclonic eddy component. Objective classification of wind fields with respect to the prevailing flow direction is performed, and wind stress and wind-curl patterns are obtained for major events in the cold and warm periods of the year. The pattern obtained can be used in hydrodynamic numerical models of the general circulation of the Japan Sea.     

Species, tissue and gender-related organochlorine bioaccumulation in white-sided dolphins, pilot whales and their common prey in the northwest Atlantic

Organochlorine concentrations were measured in white-sided dolphins, pilot whales, and their prey from the Gulf of Maine and used to identify species, tissue, and gender differences, and trophic transfer trends, in bioaccumulation. Polychlorinated biphenyl concentrations ([PCB]) in dolphin blubber (13 +/- 7.1 micrograms/g fresh wt.) were twice those in pilot whales, but pesticide concentrations (20 +/- 13 micrograms/g fresh) were similar between species. 4,4'-DDE, trans-non-achlor, Cl6(153) and Cl6(138) concentrations were highest. Skin tissues had more recalcitrant organochlorines than the internal organs. Male dolphins bioaccumulated higher concentrations of nonmetabolizable PCBs and hexachlorocyclohexane (HCH) isomers, whereas pilot whales had no gender-related differences in bioaccumulation. Pilot whales, mackerel, and herring had proportionately higher concentrations of DDTs, whereas [PCB] were higher in dolphins and squid. Although these odontocetes feed at the same trophic level and store a similar suite of contaminants, dolphins bioaccumulated higher and potentially hazardous 4,4'-DDE and PCB concentrations from food in their more geographically restricted range.     

The mixing efficiency and the processes of restratification in a stably stratified medium

The mechanism of the effect of a collapsing turbulent eddy on diapycnal transport in a stably stratified fluid is considered. It is shown that at small Richardson turbulent numbersRi ₀ the mixing efficiency increases asRi ₀, and at large numbers it decreases in proportion toRi ₀ ^–1/2 .Translated by Mikhail M. Trufanov. UDK 551.465.15.     

The structure,dynamics, and transformation of the estuary lenses in run-off seawater on the shelf of Guinea

Peculiarities of the dynamics and the structure formation in the estuary run-off lenses have been analysed based on field data obtained at the Guinean coast (the central eastern Atlantic Ocean). Attention was paid to the processes of restratification, internal mixing, and exchange in the areas of the frontal zone of the run-off lens and the tidal frontal zone. The stabilization of the front of the estuary run-off lens by means of the periodic washing out of its forepart by tidal upwelling is described. The mechanisms of the energy transformation in the leading part of the lens have been revealed. Effects of run-off and loczalization of transformed waters in the small-scale frontal zones are found. The energy estimations represented will be useful in considering analogous phenomena in other coastal regions.Translated by Mikhail M. Trufanov.     

Long-term Sensor Drift Found in Recovered Argo Profiling Floats

We recovered three Argo profiling floats after 2 to 2.5 years of operation, and recalibrated their temperature, conductivity, and pressure sensors. The results demonstrate that these floats exhibited a significant drift in salinity of −0.0074 to −0.0125, primarily due to the conductivity sensor drift. Combined with the recalibration result for another previously recovered float, the indication is that the negative salinity drift increases nearly in proportion to the operating period of floats. The increasing rate is −0.0041 (±0.0015) year⁻¹, which yields a salinity drift of −0.016 (±0.006) for the expected float lifetime of four years. The present result suggests that reducing the float surfacing time would improve the accuracy of the salinity measurements.     

Composition and quantitative distribution of macrozoobenthos in Amur Bay

The data on the species composition, trophic structure, and distribution of macrozoobenthos in Amur Bay obtained in 2001 are presented. Long-term changes in the benthos are analyzed. In 2001, the total benthos biomass significantly increased, although the parameters of the species richness declined as compared to 1986–1989. In 2001, as well as in the 1970s and 1980s, the benthos trophic structure was characterized by the prevalence of deposit feeders. The entire structure of the benthos is evaluated as an eutrophic one. Eutrophication of the bay is considered to be the most probable cause of the negative changes in the benthic communities of the bay in 2001, as well as 15 years ago.     

Water vapor in the atmosphere over the northern Tien Shan

Refined data of systematic measurements of total water vapor in the atmosphere from May 1980 to April 2005 are presented. The data were obtained at the Issyk Kul atmospheric-monitoring station by the method of solar molecular-absorption spectroscopy. Over 25 years, the annual mean water-vapor content in the atmosphere increased by 4.5% at a mean rate of increase of 0.18% per year. However, the water-vapor content decreased in the last five years. The results of statistical processing of experimental data (general statistical characteristics, correlation coefficients, composite oscillations) are described. A refined model is proposed for forecasts of temporal variations in the monthly mean and annual mean water-vapor contents for the coming years. The model includes a linear trend and the sum of oscillations with periods close to the periods of a number of well-known geophysical phenomena. Regression equations are proposed to relate the water-vapor content in the atmospheric column to the surface temperature and absolute humidity.