Sakhalin Bay Research Articles

10.1007/s11491-008-1004-8

During the summer seasons of 2002 and 2004, the total alkalinity (TA) and dissolved calcium (Ca) were studied at 41 stations in different areas of the Sea of Okhotsk: the Kuril depression, Deryugin Basin, the slopes of the Kamchatka Peninsula and Sakhalin Island, and in Sakhalin Bay. It was shown that the distributions of the TA and Ca in the water mass of deep sea areas are determined by the processes of CaCO3 formation and dissolution according to the relation Δ Ca = 0.5 Δ TA (1). The variations of the TA and Ca values observed in the upper 10-m layer and in the near-bottom layers of local depressions in the Deryugin Basin do not satisfy relationship (1). Probable reasons for this discrepancy are considered: organic matter mineralization, mixing of water masses with different preform TA and Ca values, sea ice melting, runoff from land, and sea bottom effects. It is shown that the enrichment in the alkalinity and calcium is caused by the Amur River runoff in the desalinated sea surface layer and by the high geochemical activity in the Deryugin Basin in the near-bottom 200-m layer of local depressions.

Seasonal migrations of Sea of Okhotsk beluga whales (Delphinapterus leucas) of the Sakhalin-Amur summer aggregation

Seasonal migrations of beluga whales from the Sakhalin-Amur aggregation in the Sea of Okhotsk were investigated with the use of satellite telemetry. Satellite tags were attached to four females captured near Chkalova Island, Sakhalin Bay, in August 2007. At 5 weeks after tagging, the belugas left the Chkalova Island area and moved to the Nikolaya and Ul’banskii Bays in the Shantar Sea. The animals stayed in these bays (mainly in Nikolaya Bay) until the end of autumn and then traveled northward to deeper waters. In winter and spring, they preferred to stay in the regions with dense ice cover or close to the ice edge. During the winter migration, the tagged whales, as a rule, did not keep together, although they followed the same course with a little time lag. The female whose tag transmitted the longest (9.5 months) returned to Chkalova Island in late May and thus completed the seasonal migration cycle. Based on the data on the migration routes of the tagged belugas, we suggest that the Sakhalin-Amur and Shantar aggregations interact in autumn. It is also possible that they have similar winter migratory paths

Dehydrodecalin derivative from marine isolate of the fungus Wardomyces inflatus

In connection with the program to discover biologically active compounds in extracts of marine isolates of microscopic fungi, we tested 1000 strains of marine fungi isolated from marine sediments of Sakhalin Bay for the presence in their extracts of compounds with antibiotic activity that were active in early embryogenesis of the sea urchin Strongylocentrotus intermedius. One of them, Wardomyces inflatus (Marchal) Hennebert, synthesized such compounds. This fungus is usually parasitic on terrestrial plants [1, 2] and was isolated by us for the first time from deep (50 m) marine sediments. Mycelium of the fungus with medium was extracted twice with EtOAc. The extract was evaporated. The solid was dissolved in EtOH:H 2 O (1:4) and extracted (2×) successively with hexane, CHCl 3 , and BuOH. The CHCl 3 extract was evaporated in vacuo. The dry solid (700 mg) was chromatographed over a column (25 × 2 cm) of SiO 2 . Compound 1 (27 mg) was eluted by hexane:EtOAc (85:15). The UV spectrum of the compound had no absorption bands. Its IR spectrum showed absorption bands characteristic of hydroxyls (3621, 3568 cm –1 ). The PMR and 13 C NMR spectra of 1 (Table 1) was consistent with two quaternary C atoms (δ C 52.6, C-1; 215.7, C-9) and eight methines (δ H 1.94–δ C 52.3, C-2; δ H 5.70–δ C 123.9, C-3; δ H 6.0–δ C 126.1, C-4; δ H 2.14–δ C 39.0, C-4a; δ H 3.43–δ C 75.3, C-5; δ H 4.04–δ C 69.6, C-6; δ H 1.74–δ C 30.5, C-8; δ H 1.93–δ C 43.0, C-8a; δ H 1.12–δ C 37.1, C-1′), two of which were bound to C-5 and C-6, which were oxygenated, and two of which were located on the C-3–C-4 double bond. The position of the resonances for the C-3 and C-4 protons and their SSCC indicated that they were situated cis to each other on the double bond. Besides these resonances, spectra of 1 contained resonances for four methyls (δ H 0.59–δ C 22.4, CH 3 -12; δ H 0.75–δ C 12.5, CH 3 -3′; δ H 0.93–δ C 19.2, CH 3 -4′; δ H 1.25–δ C 19.4, CH 3 -13), the multiplicity of which indicated that one of them was bound to a quaternary C atom; two, to a tertiary; and one, to a secondary. The chemical structure was determined from the 1 H– 1 H COSY and HSQC spectra incorporating HMBC correlations

Numerical model studies on the generation and dissipation of the diurnal coastal-trapped waves over the Sakhalin shelf in the Sea of Okhotsk

To clarify the generation and dissipation mechanisms of diurnal coastal-trapped waves (CTWs) over the Sakhalin shelf, a series of numerical experiments were conducted using a three-dimensional tidal model of the Okhotsk Sea with density stratification. The tidal model used has good reproduction owing to the careful fitting to the recent observations. The numerical experiments suggested that diurnal CTWs are primarily (~60%) generated by the conversion of tidal energy at the northern corner of the Sakhalin shelf, and further amplified by vorticity generation due to the water column oscillation from Sakhalin Bay and the influence of Kashevarov Bank. From the observations, it was found that diurnal CTWs are effectively dissipated by the strong spin-down due to bottom friction. The conventional turbulent closure model cannot reproduce the observed damping of diurnal CTWs, which raises a caution in modeling the tidal fields in high-latitude regions where diurnal CTWs exist. To resolve this underestimation of the damping, the vertical eddy viscosity was parameterized using its dependence on the observed major axis length of the diurnal tidal current ellipses, which improves the model reproduction on the damping of diurnal CTWs. The model also suggests that the spin-down effects due to friction associated with the sea-ice cover play an important role in the tidal current reduction in the region where diurnal CTWs exist, as the observations suggested.

Bacterioplankton and bacteriobenthos of the Amur estuary and the adjacent areas in the Summer of 2006

This work presents the results of the study of the plankton and benthic microbiocenoses of the Amur estuary. It is shown that the distribution of the total abundance and indicator groups of the bacteriobenthos are characterized by stronger heterogeneity compared with the bacterioplankton and that it depends on the Amur river drainage and the bottom type. The river drainage helps by increasing the overall bacterioplankton abundance in the near-mouth part of the estuary. Microorganisms utilizing low concentrations of OM play a major role in the processes of the OM utilization in the water and bottom sediments. Saprophytic bacteria play a significant role in the OM utilization only in the water at certain sampling sites in the Tatarskiy Strait and Sakhalin Bay and in the bottom sediments taken in the mouth part of the estuary. Some parts of the estuary subject to organic contamination are found according to the microbiological characteristics. It is shown that the fluctuation of the salinity leads to a change of the share of bacteria with different food demands in the microbial community.

Phytoplankton growth and microzooplankton grazing in the Sea of Okhotsk during late summer of 2006

The Sea of Okhotsk is one of the most productive marine basins in the world ocean and plays an important role in transport of organic carbon and iron to the western subarctic Pacific. We report the first measurements of phytoplankton growth and microzooplankton grazing rates in the Sea of Okhotsk, in late summer of 2006. The study area can be divided into two areas: nutrient-sufficient waters on the continental shelf along the east coast of Sakhalin Island and in the vicinity of Bussol Strait, and surface nutrient-depleted waters beyond the shelf break and in the vicinity of Sakhalin Bay. Phytoplankton growth rate in the studied area was strongly affected by nutrient availability, with high phytoplankton growth rate (0.55±0.14 d −1) in the nutrient-replete region and severely depressed growth (0.03±0.05 d −1) in the nutrient-depleted region. On the other hand, microzooplankton grazing rates in both the nutrient-replete and nutrient-depleted regions were approximately the same (0.26±0.20 d −1 vs. 0.27±0.24 d −1). Consequently, microzooplankton grazing consumed <50% of the phytoplankton growth in nutrient-rich waters but >3 times the phytoplankton growth in nutrient-depleted waters. Phytoplankton physiological condition as measured by the maximum photochemical quantum efficiency ( F v / F m ) of algal photosystem II (PS II) showed a general trend in agreement with the in situ growth rate of phytoplankton. In contrast to the phytoplankton community, picophytoplankton, especially the cyanobacteria Synechococcus, showed no nutrient effect on their growth, and the growth and mortality rates were well balanced, suggesting that they have a low nutrient requirement and their biomass was controlled principally by microzooplankton grazing.

Distribution of alkalinity and dissolved calcium in the Sea of Okhotsk

During the summer seasons of 2002 and 2004, the total alkalinity (TA) and dissolved calcium (Ca) were studied at 41 stations in different areas of the Sea of Okhotsk: the Kuril depression, Deryugin Basin, the slopes of the Kamchatka Peninsula and Sakhalin Island, and in Sakhalin Bay. It was shown that the distributions of the TA and Ca in the water mass of deep sea areas are determined by the processes of CaCO3 formation and dissolution according to the relation Δ Ca = 0.5 Δ TA (1). The variations of the TA and Ca values observed in the upper 10-m layer and in the near-bottom layers of local depressions in the Deryugin Basin do not satisfy relationship (1). Probable reasons for this discrepancy are considered: organic matter mineralization, mixing of water masses with different preform TA and Ca values, sea ice melting, runoff from land, and sea bottom effects. It is shown that the enrichment in the alkalinity and calcium is caused by the Amur River runoff in the desalinated sea surface layer and by the high geochemical activity in the Deryugin Basin in the near-bottom 200-m layer of local depressions.

Dense water production on the northern Okhotsk shelves: Comparison of ship‐based spring‐summer observations for 1996 and 1997 with satellite observations

For the northern Okhotsk Sea polynyas, five Russian CTD surveys taken during 1995 to 1997 are used to examine the evolution of the polynya dense water. The surveys show that consistent with other investigations, the largest potential densities are 26.99 σθ, and the densest water occurs in Sakhalin and Shelikhov Bays. The surveys also suggest that the Shelikhov water drains directly into the deep Okhotsk, while on the northern shelves, gravity currents transport the dense water west to Sakhalin Bay. For comparison, determination of the polynya sizes and ice production from satellite passive microwave and meteorological observations shows that polynyas occur on the northwest shelf (NWS) between Ayan and Okhotsk City, on the northern shelf between Okhotsk City and Magadan, and in Shelikhov Bay. In contrast, the observations show that Sakhalin Bay is a region of land fast ice with no polynyas, so that the dense water observed here cannot form locally. For all polynyas the satellite observations show that the NWS contributes 60 to 70% of the total ice production, and due to the warmer 1997 air temperatures, the 1996 production is about 1.5 times the 1997 value. An estimate of the ice production from the surveys shows a similar regional distribution and enhancement of the 1996 production, with the satellite and ship estimates in agreement within their error bars. Finally, analysis of the dense water outflow shows that the upper Okhotsk Sea Mode Water has a renewal time of about 4 years; the lower part, about 14 years.