Composition of aerosols collected in the Western Russian Arctic in August-September 1991

In August-September 1991 during the SPASIBA expedition (Scientific Program on the Arctic and Siberian Aquatorium) aboard R/V Yakov Smirnitzky in the Laptev Sea ten samples of aerosols were collected by nylon nets. A combined approach including various analytical techniques, such as single-particle analysis, instrumental neutron activation analysis, and atomic absorption spectrophotometry, was used to study composition of the samples. Mass concentration of coarse-grained (>0.001 mm) insoluble fraction of aerosols ranged from 80 to 460 ng/m**3. In all the samples remains of land vegetation were found to be the dominant component. Organic carbon content of the aerosols ranged from 23 to 49%. Inorganic part of the samples was represented mainly by alumosilicates and quartz. Anthropogenic ''fly ash'' particles were observed in all the samples. Temporal variations of element concentrations resulted from differences in air masses entering the studied area.

Dissolved oxygen, nitrate, nitrite, and ammonum in waters of the Arabian Sea

Distribution of ammonium, nitrite and nitrate nitrogen is examined in a section along 65-67°E between 18°S and 23°N during the transition period from winter to summer monsoons. It is shown that, under conditions of very large oxygen deficit in the 200-400 m layer, denitrification process results in formation of the second deep-sea maximum of nitrites and the intermediate minimum of nitrate nitrogen.

Finely dispersed fraction of particulate organic matter and primary production in sea water of the Equatorial East Pacific

Qualitative and quantitative evaluation of the finely dispersed fraction of particulate organic matter in sea water is given. It is demonstrated that in the euphotic zone of high productivity waters this fraction constitutes 86%, in waters with low productivity 61%, and in deep waters (>200 m) 53% of the organic carbon in particulate matter. Formation of the finely dispersed fraction and its role in distribution of energy in the detrital food chain of the ecosystem are discussed.

Concentrations of labile dissolved forms of Cu, Zn, Pb, and Cu in waters of the Kara Sea and Ob and Yenisey estuaries

Concentrations of labile dissolved forms of Cu, Zn, Pb, and Cu in waters of the Kara Sea and Ob and Yenisey estuaries measured on board during Cruise 49 of R/V Dmitry Mendeleev.

Dissolved and particulate organic carbon in the Sea of Okhotsk

Data on distribution of dissolved and particulate organic matter obtained during Cruises 21 and 24 of R/V Akademik A. Nesmeyanov in June-August 1992 and 1993 are presented. In general a remarkable heterogeneity in distributions of both dissolved and particulate organic carbon is revealed. Concentrations of dissolved organic carbon vary from 98 to 700 µmol/l and those of particulate organic carbon vary from 3 to 50 µmol/l. Maximum concentrations are commonly observed in the shelf region while minimum concentrations - in the central basin. Run-off of the Amur River raises dissolved matter concentration in the Sakhalin Bay, while oil exploitation at the Sakhalin shelf maximizes particulate organic carbon concentration and minimizes dissolved one. Concentrations of dissolved and particulate organic carbon in the surface microlayer were estimated for the first time and are shown to be 1.5-2.0 times higher than in surface waters.

Iron and manganese in bottom sediments and interstitial waters sampled in the White Sea on August 21-30, 2003

Iron and manganese in bottom sediments studied along the sublatitudinal transect from Kandalaksha to Arkhangelsk are characterized by various contents and speciations depending on sedimentation environment, grain size of sediments, and diagenetic processes. The latter include redistribution of reactive forms leading to enrichment in Fe and Mn of surface sediments, formation of films, incrustations, and ferromanganese nodules. Variations in total Fe content (2-8%) are accompanied by changes in concentration of its reactive forms (acid extraction) and concentration of dissolved Fe in interstitial waters (1-14 µM). Variations in Mn content in bottom sediments (0.03-3.7%) and interstitial waters (up to 500 µM) correspond to high diagenetic mobility of this element. Changes in oxidation degree of chemical elements result in redox stratification of sediment strata with maximum concentrations of Fe, Mn, and sulfides. Organic matter of bottom sediments with considerable terrestrial constituent is oxidized by bottom water oxygen mainly at the sediment surface or in anaerobic conditions within the sediment strata. The role of inorganic components in organic matter oxidation changes from surface layer bottom sediments (where manganese oxyhydroxide dominates among oxidants) to deeper layers (where sulfate of interstitial water serves as the main oxidant). Differences in river runoff and hydrodynamics are responsible for geochemical asymmetry of the transect. The deep Kandalaksha Bay serves as a sediment trap for manganese (Mn content in sediments varies within 0.5-0.7%), whereas the sedimentary environment in the Dvina Bay promotes its removal from bottom sediments (Mn 0.05%).

Vertical distribution of relative numbers of the main groups of sound-scattering fishes in the Central Indian Ocean

Findings made in 31 catches with an Isaacs-Kidd midwater trawl in the light (09.00-16.00) and dark (21.00-04.00) periods of a day within a survey area of about 100 sq. miles with approximate center coordinates of 13°S and 78°E have been used to investigate vertical distribution of the main groups of sound-scattering fishes (35 species of the family Myctophidae and 16 species of other families). It has been shown that during daylight hours all fishes sink to depths deeper than 400 m. Data are presented concerning the fish population of night-time sound-scattering layers at depths of 70-150 m and about 400 m and of the daytime ones at depths of about 450 m.