Phytoplankton characteristics and hydrological conditions in the western part of the Sea of Okhotsk in the spring of 1999 and 2000 based on expeditionary and satellite data

Zakharkov, S. P.; Селина, М. С.; Ванин, Н. С.; Shtraikhert, E. A.; Biebov, N.

doi:10.1134/s0001437007040091

Cited by 9 publications

(3 citation statements)

References 8 publications

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“…In particular, T. nordenskioeldii usually dominates the spring phytoplankton bloom in the shelf surface waters of the Sea of Okhotsk with water temperatures of 2-5 • C and salinities of 20-27 (Sorokin and Sorokin, 1999). There is evidence that Thalassiosira is abundant in the eastern coastal waters of Sakhalin Island along the moving path of the drift ice in winter and after ice retreat (Sorokin and Sorokin, 1999;Leonov et al, 2007;Zakharkov et al, 2007). We thus suggest that Thalassiosira could be a common component in the drift ice of the Sea of Okhotsk and they play important roles in the drift ice and seawater in the Sea of Okhotsk during the winter and the ice melt season.…”

Section: Discussionmentioning

confidence: 99%

Response to Sea Ice Melt Indicates High Seeding Potential of the Ice Diatom Thalassiosira to Spring Phytoplankton Blooms: A Laboratory Study on an Ice Algal Community From the Sea of Okhotsk

et al. 2020

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Phytoplankton communities in seasonally ice-covered areas are largely affected by ice algae. The Okhotsk Sea is the southernmost sea ice zone in the northern hemisphere with a sizeable seasonal ice cover, thus ice algae of the Okhotsk sea ice have a large potential to seed the early spring bloom. Little is known about the Okhotsk ice algal communities and their seeding effects. We investigated the dynamics of the composition and the photophysiological performances of an Okhotsk ice algal community in a 6day laboratory incubation experiment that simulated the natural ice melt conditions. Centric diatoms, especially Thalassiosira spp., overwhelmingly dominated the ice algal community throughout incubation, whereas pennate diatoms, mostly Navicula and Nitzschia, showed little growth with much higher mortality. The maximum photochemical efficiency of Photosystem II (F v /F m) was the lowest at the beginning of the ice melt, suggesting a suppressed photosynthetic functioning by changes in salinity. The cellular pigment contents decreased by 30% due to osmotic stress, evidenced by deformed plastids under a microscope. The transcript level of the rbcL gene that encodes the large subunit of RubisCO was significantly higher during ice melt and decreased in the no-ice period, suggesting an urgent need for carbon fixation under the melt condition. Full recovery of photosynthesis and growth was also made after complete ice melt. Our results indicated high seeding potential of Thalassiosira to spring blooms owing to their photophysiological plasticity to dynamic salinity changes.

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Section: Discussionmentioning

confidence: 99%

Response to Sea Ice Melt Indicates High Seeding Potential of the Ice Diatom Thalassiosira to Spring Phytoplankton Blooms: A Laboratory Study on an Ice Algal Community From the Sea of Okhotsk

et al. 2020

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“…The Nearshore and Offshore feeding areas are within the region of highest primary and secondary production in the Okhotsk Sea [ 31 , 33 – 40 ]. Strong winds, tidal mixing, upwelling, and Amur River discharges over the northeastern Sakhalin Shelf induce intense diatom blooms in these areas during the ice free May-November period [ 37 , 41 – 43 ].…”

Section: Introductionmentioning

confidence: 99%

Life History and Production of the Western Gray Whale’s Prey, Ampelisca eschrichtii Krøyer, 1842 (Amphipoda, Ampeliscidae)

et al. 2016

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Ampelisca eschrichtii are among the most important prey of the Western North Pacific gray whales, Eschrichtius robustus. The largest and densest known populations of this amphipod occur in the gray whale’s Offshore feeding area on the Northeastern Sakhalin Island Shelf. The remote location, ice cover and stormy weather at the Offshore area have prevented winter sampling. The incomplete annual sampling has confounded efforts to resolve life history and production of A. eschrichtii. Expanded comparisons of population size structure and individual reproductive development between late spring and early fall over six sampling years between 2002 and 2013 however, reveal that A. eschrichtii are gonochoristic, iteroparous, mature at body lengths greater than 15 mm and have a two-year life span. The low frequencies of brooding females, the lack of early stage juveniles, the lack of individual or population growth or biomass increases over late spring and summer, all indicate that growth and reproduction occur primarily in winter, when sampling does not occur. Distinct juvenile and adult size cohorts additionally indicate growth and juvenile production occurs in winter through spring under ice cover. Winter growth thus requires that winter detritus or primary production are critical food sources for these ampeliscid populations and yet, the Offshore area and the Eastern Sakhalin Shelf ampeliscid communities may be the most abundant and productive amphipod population in the world. These A. eschrichtii populations are unlikely to be limited by western gray whale predation. Whether benthic community structure can limit access and foraging success of western gray whales is unclear.

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“…OHC-oxidizing bacteria B2 consume the OHC content available in the water environment. The dominant groups of phytoplankton are diatoms (F1), and other groups (F2 and F3) (Zakharkov et al, 2007;Mogil'nikova et al, 2003) consume the mineral BS for the formation of their biomass, and with their lack -and some fraction of organic fractions of biogenic elements. The functional role of zooplankton is reduced to the regulation of the development of other organism biomasses (or the rate of growth of their biomass), which on the whole indirectly affects the biotransformation of BS and OM in the aquatic environment.…”

Section: Introductionmentioning

confidence: 99%

Oil Hydrocarbons in Shelf Waters of the Eastern Part of the Sakhalin Island: Their Inputs, Transformations and Contents

Леонов

Pishchal’nik

Петухов

et al. 2019

JOR

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On the basis of the methodology of mathematical modeling, the development of the transformation of oil hydrocarbons in the waters of the eastern shelf of Sakhalin Island is considered. Three electronic instruments for the analysis of oceanographic information were used: 1. GIS “Sakhalin shelf” (for processing and systematization of thermohaline observed parameters); 2. The oceanic model of the Bergen University (for calculating the velocities and directions of currents, and also flow rates of water exchange between the individual regions on the Sakhalin Shelf); and 3. CNPSi-model (for calculating the biotransformation of oil hydrocarbons taking into account the intra-annual changes of the long-term marine environment parameters and features of the substance transfer at the water exchange). The entire eastern shelf of the Sakhalin Island was subdivided on two Water Areas (1. southeastern and 2. northeastern ones), where Regions 1–3 and 1–4 were respectively allocated. Using the methodology of mathematical modeling, the CNPSi-model reproduces the interactions of the changing environmental factors during a year (temperature, light intensity, water transparency, oil hydrocarbon inputs from external sources, conditions of the water regime) and their influence on the biotransformation of oil hydrocarbons in two-layer marine environment. The model calculates the changes during a year of the oil hydrocarbon concentrations, the biomass of B2 bacteria (they oxidize of the oil hydrocarbons) and their activity indexes (the specific growth rate, the total biomass turnover time and the biomass production). An analysis is made of the changes in these parameters depending on environmental factors and conditions of substance transport during water exchange across the boundaries of regions and with open water areas of the Sea of Okhotsk. For each region studied, the characteristic values of these parameters were revealed for specific periods of a year. Calculations show that there are different conditions for the formation of B2 bacteria biomass and their production on the south and north regions of the eastern shelf of the Sakhalin Island. In Regions 1–3 of the southeastern part of the shelf (Area 1), a significant effect of water dynamics was found on the development of the biomasses of organisms and, in particular, on the B2 biomass.

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Phytoplankton characteristics and hydrological conditions in the western part of the Sea of Okhotsk in the spring of 1999 and 2000 based on expeditionary and satellite data

Cited by 9 publications

References 8 publications

Response to Sea Ice Melt Indicates High Seeding Potential of the Ice Diatom Thalassiosira to Spring Phytoplankton Blooms: A Laboratory Study on an Ice Algal Community From the Sea of Okhotsk

Response to Sea Ice Melt Indicates High Seeding Potential of the Ice Diatom Thalassiosira to Spring Phytoplankton Blooms: A Laboratory Study on an Ice Algal Community From the Sea of Okhotsk

Life History and Production of the Western Gray Whale’s Prey, Ampelisca eschrichtii Krøyer, 1842 (Amphipoda, Ampeliscidae)

Oil Hydrocarbons in Shelf Waters of the Eastern Part of the Sakhalin Island: Their Inputs, Transformations and Contents

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