Spatial variability of thermohaline characteristics (temperature, salinity, and dissolved oxygen) and phytoplankton structure (composition, abundance, and biomass) of the Southern Ocean during austral summer were investigated. New data were obtained for a little-studied area of Antarctica: on transects along the eastern border of the Ross Sea along W156° (T1, length of 35 km, 6 stations), near the Russkaya station (T2, 87 km, 13 stations), at the single station (Roosevelt Island area, Bay of Whales, Ross Sea), and in the Bransfield Strait (T3, 118 km, 11 stations). The relevance of the analysis of this area is due to its location on the border of the shelf and continental slope with different parameters of temperature and water structure. Low salinity and different temperature characteristics were revealed in surface waters of T1 and T2: lower values for T2 (−1.5 °C) and higher for T1 (0 °C). For the Bransfield Strait waters (T3), typical data on salinity and oxygen content were obtained against the backdrop of slightly increased temperature (up to +2 °C). For the single station, relatively fresh, cold, and oxygenated water of the upper 100-meter layer was recorded, and low temperature values of the bottom area, with high mineralization, were registered. In the phytoplankton composition of the study area, 48 taxa of microalgae from 5 divisions were identified (Bacillariophyta, 38; Dinophyta, Cyanoprokaryota, and Chrysophyta, 3 taxa each; and Haptophyta, 1) and 1 macrophyte taxon (Rhodophyta). The maximum similarity in the species composition of phytoplankton (on average, 43%) was typical for shelf stations in different areas. The total abundance of phytoplankton in the study area of the Southern Ocean ranged within 4.3–264.0 thousand cells·L−1, and biomass, 0.07–1.18 mg·L−1. The main contributors to quantitative characteristics of phytoplankton throughout the study water area were diatoms, mainly representatives of the genus Fragilariopsis Hustedt, confined to the shelf and coastal areas. At a distance and in the open sea of transects T1 and T2 deeper than 50 m and in surface waters of transect T3, Phaeocystis antarctica Karsten (Haptophyta) developed in mass. For T2, the dependence of phytoplankton abundance on water temperature and salinity was revealed.
Coastal seagrass ecosystems, particularly Zostera marina Linnaeus, 1753 ones, are capable of accumulating organic carbon by fixing carbon dioxide via photosynthesis. Seagrass biomass is considered as a short-term carbon storage, and underlying bottom sediments, as a long-term one. The research on organic matter accumulation by seagrass ecosystems is mostly carried out in areas with stable sedimentation. For such ecosystems, the importance of seagrass areas within the concept of blue carbon was shown. However, for the seas of temperate latitudes, coastal waters with unstable sedimentation and prevalence of sandy sediments are common, and the scale of carbon storage in seagrass ecosystems is not obvious. In this work, biomass and carbon stock in Z. marina leaves and roots, as well as Corg concentration and carbon stock in the upper layers of bottom sediments (0.25-m and 1-m thick), were determined for typical habitats in the semi-open Srednyaya Bight (Peter the Great Bay, the Sea of Japan), where sandy sediments prevail. Z. marina roots were characterized by 3–20 times lower biomass than its leaves. This difference increased from April to July in accordance with seasonality. Carbon concentrations in the seagrass leaves and roots were similar (33.3 and 31.3% dry weight, respectively). In the habitats with a projective coverage of 50–80%, carbon stock in Z. marina tissues was (96.8 ± 37.4) g C·m−2; with 100% coverage, the value increased to 253 g C·m−2. Corg concentration in bottom sediments of the Srednyaya Bight ranged within 0.04–0.46% and correlated with content of silt fractions. Under dense Z. marina coverage, Corg content and the fraction of silt particles in sediments were higher than under sparse ones. The vertical distribution of Corg concentration within the upper 15–35-cm layer did not reveal a downward trend in the cores. The main factor controlling Corg content was the particle-size distribution of sediments, which suggests a weak expression of reduction diagenesis and the effect of wave mixing of the upper layer of sandy sediments. Data on the bulk density and Corg concentration in sediments allowed to calculate carbon stock for the layers of 0.25 and 1 m. The quota of organic carbon in the seagrass tissues did not exceed a third of its amount in the upper layer (0.25 m) of underlying sandy sediments. When extrapolated to a 1-m thick layer, the quota of bottom sediments to Corg pool exceeds 90%. Organic carbon enrichment of sandy sediments under the seagrass beds compared to sands of similar particle size beyond the seagrass beds indicates a significant role of Z. marina in carbon storage, even in the habitats with the lack of stable and intensive sedimentation. The major factor controlling carbon stock in Z. marina ecosystems is Corg content in underlying bottom sediments which depends primarily on their particle-size distribution. In this case, the range of variation in carbon stock in the upper layer is an order of magnitude or more. Maps of the seagrass distribution in April and July 2021 were built. The absolute values of carbon stock were calculated, both accumulated in Z. marina biomass and deposited in the seagrass-covered sediments. The area of potential Z. marina distribution in the Srednyaya Bight was modelled using the MaxEnt 3.4.4 program. According to the results, areas with a predicted probability exceeding 0.5 for the seagrass occurrence occupy about a third of the total area of the bight; out of them, the area with a probability of Z. marina occurrence exceeding 0.75 accounts for 11.83 hectares. In fact, the seagrass meadows occupied > 70% of the area with a predicted probability of the species occurrence exceeding 0.5. As shown, the assessment of the contribution of seagrass ecosystems to the storage of carbon accumulating in the coastal zone requires differentiation of water areas by sedimentation regimes and types of bottom sediments. Moreover, the creation of databases with data on Corg concentration and stock per unit area is needed. Information on the areas of ecosystem distribution obtained by direct mapping and remote sensing is of high significance as well.
The Western Pacific gastropod Rapana venosa (Valenciennes, 1846) is classified among the hundred most dangerous invasive species of the Black and Mediterranean seas. Moreover, it is recognized as a dangerous invader in a number of coastal water areas on both sides of the Atlantic Ocean that determines the relevance of the study of population characteristics and biocenotic relationships of the rapa whelk in the areas of its invasion. The analysis of a previously unexplored R. venosa population in the Donuzlav Bay (the Northwestern Crimea) of the Black Sea in 2020 showed as follows: in the occurrence of an abundant and diverse food base, the rapa whelk does not form mass aggregations and, consequently, does not significantly affect benthic biocenoses. This fact is also confirmed by the ratio of biomass of the predatory mollusc and its prey. R. venosa mean biomass in the study area was 3.8 g·m−2, and the mean biomass of its food objects (Bivalvia) was 162.8 g·m−2. The features of the population structure and biocenotic relationships of the rapa whelk in the Donuzlav Bay are considered and discussed for the first time. Direct underwater observations and indirect evidence indicate that the distribution of this invader is controlled by aboriginal predators, crabs. The main species limiting R. venosa abundance in the study area is the crab Carcinus aestuarii Nardo, 1847.
Symbioses are common relationships between organisms in marine ecosystems. Out of crabs belonging to the family Portunidae, an economically important one, Charybdis truncata (Fabricius, 1798) is a widely distributed species. However, the studies on its symbiotic assemblages are still limited. A total of 408 C. truncata were sampled in Nha Trang Bay (Khanh Hoa province, Vietnam, the East Sea) in January–August 2022. Symbionts were classified based on morphological characters. Statistical analysis was applied to compare the infestation status of symbionts. Six symbiotic species were detected, including four epibiotic barnacles [Octolasmis angulata (Aurivillius, 1894), Octolasmis alata (Aurivillius, 1894), Octolasmis warwicki Gray, 1825, and Dianajonesia tridens (Aurivillius, 1894)] and two obligate unidentified parasites [Cancrion sp. and Sacculina sp.]. Out of them, O. alata and Cancrion sp. were recorded on C. truncata for the first time. The overall prevalence of symbionts on the swimming crab hosts was 13%, and the number of infecting symbiont species on hosts ranged within 1–4. O. angulata was the dominant species, with the prevalence of 6.9%. The prevalence of this symbiotic species was significantly higher in ovigerous female crabs compared to non-ovigerous ones. Moreover, there was a noticeable rise in O. angulata prevalence rates as crab size increased. No significant differences were revealed in the mean intensity of symbionts by sex, reproductive status of females, and size of the crab hosts. The initial morphological modifications caused by infecting parasites, Cancrion sp. and Sacculina sp., were recorded and described. These findings provide data on the status of natural infection of symbiotic species on C. truncata as a basis for the management of commercial species and aquaculture development.
Chitons inhabiting natural hard substrates in the Tsemes Bay pseudolittoral from the central beach of Novorossiysk to the Cape Khako were investigated in summer and winter periods of 2022–2023. For the first time in the Tsemes Bay, a local population of Lepidochitona cinerea (Linnaeus, 1767) (Polyplacophora, Tonicellidae) was recorded on substrates of sedimentary origin. It is a rare species, and over the past 70 years, it was found in waters of the North Caucasus only three times. We registered 34 L. cinerea specimens with a maximum shell length of 8 mm. The age of the largest individuals (three years) was determined by the annual rings of the apex of the first shell shield. The species is distributed in the upper horizon of the Cape of Love pseudolittoral and is confined to supralittoral baths. A similar biotope, where the chiton was found as well, was discovered in 50 km from the Tsemes Bay. As assumed, the occurrence of the mollusc in the water area is precisely due to the presence of this bionomic type of habitat – supralittoral baths which are not expressed in other study sites of the bay. The aim of the research is to describe L. cinerea populations in a previously unspecified biotope for this species and to identify the features of this biotope and its possible effect on the chiton occurrence. Information on the geographic distribution and biotopic confinement of the species was updated. The effect of ecological, hydrochemical, and geomorphological features of the biotope on L. cinerea occurrence was considered.
The southwestern Kara Sea is a scarce studied area in terms of summer-autumn migrations and feeding nomadism of water birds and seabirds. Its shelf includes promising areas for extraction of hydrocarbon raw materials and intensification of navigation along the Northern Sea Route, which makes it necessary to carry out constant monitoring of birds in the area of possible negative effect of those factors. In August–September 2015–2016 and 2018–2020 and in late September–first and second decades of October 2017, bird counts were carried out in the southwestern Kara Sea. Method of ship transect census was applied to obtain the abundance of individuals per 1 km². For this water area, 28 species of birds representing 7 families were identified (Gaviidae, Sulidae, Procellariidae, Anatidae, Laridae, Stercorariidae, and Alcidae), including 6 species of conservation status. For the group of water birds, the data obtained in August–October are most detailed for the black-throated diver, long-tailed duck, and king eider (Gaviidae and Anatidae). Prior to autumn migration (August), their abundance increased in the shallow area adjacent to the coast, later followed by their dispersal to deeper areas west of the Yamal Peninsula. In coastal shallow areas, the population density during the period of the most active colonization of this biotope is as follows (ind.·km−2): (0.17 ± 0.036) for the black-throated diver, (4.87 ± 1.2) for the long-tailed duck, and (2.1 ± 1.25) for the king eider. Presumably, the values are significantly higher for all three species at shorter distances from the coast not examined from the vessel. Other species of the group of water birds (the red-throated diver, Steller’s eider, dark-bellied brant goose, European white-fronted goose, and bean goose) are rare in open waters and, apparently, are mainly confined to a narrower coastal zone during the entire summer-autumn period. The same indicator of abundance of migratory seabirds (Procellariidae, Laridae, Stercorariidae, and Alcidae), calculated for the entire water area of the survey site, averaged for 5 years for August–September (ind.·km−2): (0.078 ± 0.026) for the fulmar, (0.067 ± 0.014) for the glaucous gull, (0.061 ± 0.016) for the black-legged kittiwake, (0.025 ± 0.015) for the Arctic tern, (0.066 ± 0.0049) for the Heuglin’s gull, (0.046 ± 0.0074) for the pomarine skua, (0.014 ± 0.0023) for the Arctic skua, (0.0039 ± 0.00095) for the long-tailed skua, (0.16 ± 0.094) for the Brünnich’s guillemot, and (0.0026 ± 0.0012) for the black guillemot. In late September and October, the abundance of the black-legged kittiwake, fulmar, and Brünnich’s guillemot slightly decreases or remains at the level of September one, while the abundance of the black guillemot increases by 7 times. The Arctic tern, Heuglin’s gull, and long-tailed skua disappear from the water area. The glaucous gull, pomarine skua, and Arctic skua become much rarer or almost disappear (5-, 40-, and 30-fold drop in abundance, respectively). In general, in the long-term aspect, the fulmar, three Stercorariidae species, the glaucous gull, black-legged kittiwake, Arctic tern, and black guillemot colonize the entire survey site. Interestingly, for the fulmar, black-legged kittiwake, and glaucous gull, uneven distribution is recorded in some years, which is expressed in significant (3 to 17 times) differences in abundance between large (about 25 thousand km²) spots of the studied water area. During their entire stay at the survey site, the Heuglin’s gull and Arctic tern are mainly confined to coastal shallow areas; there, up to 80–90% of the total abundance of individuals in the studied water area is concentrated during periods of seasonal maximum. On the contrary, the Brünnich’s guillemot avoids shallow areas (depth of < 50 m). Rare species are vagrant ones (the northern gannet, black-headed gull, European herring gull, and common gull), those found in the peripheral area of their common range (the great skua and grey petrel), and those considered rare at the present stage of the existence of their populations (the white-billed diver). Also, rare species are the birds with insufficiently studied main habitat (the velvet scoter, Steller’s eider, dark-bellied brant goose, bean goose, and European white-fronted goose) and seasonally rare ones (the little auk).
Under climatic and anthropogenic factors, the Black Sea ecosystem is being transformed and replenished with new species of fish and Decapoda. Therefore, regular monitoring studies become relevant which allow identifying the effect of these processes on biocenoses of the Crimean Peninsula coastal waters. The aim of this work was to investigate taxonomic, structural, and quantitative characteristics of decapods and ichthyofauna of the Black Sea in the area of the Cape Martyan nature reserve. To make the results more complete, both adult individuals and planktonic and larval stages were sampled and analyzed. Fish and decapods were sampled with fixed nets, bottom traps, and hand nets. Ichthyoplankton and Decapoda larvae were sampled with an ichthyoplankton cone-shaped net IKS-80. For decapods, a high level of species diversity was revealed: those were represented by 17 species from 14 families. Two species, Alpheus dentipes Guérin, 1832 and Lysmata seticaudata (Risso, 1816), were recorded in the study area for the first time. The taxonomic composition of ichthyofauna was formed by about 30 species, mostly benthic and demersal fish. The structure of fish communities was quite stable; there was a trend towards an increase in diversity, a decrease in the prevalence of certain species, and an overall improvement in their state. A rise in abundance of some Atlantic–Mediterranean species, such as Serranus scriba (Linnaeus, 1758) and Chromis chromis (Linnaeus, 1758), can serve as an indicator of variations in hydrological and hydrochemical parameters of the environment related to general climate and ecological changes. The values of the quantitative parameters of fish eggs and larvae, (76.3 ± 11.4) and (18.8 ± 4.6) ind.·m−2, respectively, were sufficiently high for the Black Sea coastal waters. However, the proportion of living, normally developing fish eggs in the water area was low, 28.6% of the total. The data obtained can be used for comparative analysis during long-term monitoring in the Black Sea water area.
In 1995–2019, marine algae were sampled in the intertidal and upper subtidal zones of the Amakusa Archipelago (Shimoshima islands) and the southern islands of the Ryukyu Archipelago (Okinawa, Sesoko, Ieshima, Akajima, Miyako, Ishigaki, Iriomote, and Yonaguni). A total of 569 species and taxonomic forms of benthic macroalgae were identified. Out of them, 57% belonged to red algae; 15%, to brown algae; and 28%, to green algae. On these islands, 153 taxa were found for the first time. During the specified period, the benthic marine flora of individual islands was analyzed with varying degrees of care. The most thoroughly studied island of the Amakusa group was Shimoshima (14 localities during all seasons), and of the Ryukyu Archipelago, Sesoko (8 localities during all seasons). The comparison of taxonomic and biogeographic characteristics of marine floras of these two archipelagos – biodiversity of species and forms, taxonomic composition of algal communities, and potential capabilities of geographic (latitudinal) distribution of taxa – give us the grounds to classify the Shimoshima Island as a warm-temperate region of the Northern Hemisphere in East Asia, and the southern islands of the Ryukyu Archipelago, as a tropical biogeographic region.
Atlantification of the Barents Sea leads to a decrease in the area of ice cover and an increase in the ice-free period. This process affects the entire pelagic ecosystem of the Barents Sea, where the main part of the annual primary production of phytoplankton is formed during the spring bloom. Chlorophyll a concentration reflects changes in phytoplankton biomass and can serve as an indicator of its production characteristics. In the spring of 2021, hydrological characteristics of water masses, as well as the distribution of concentrations of chlorophyll a and nutrients, were studied in the ice-free water area of the Barents Sea. The year of 2021 was characterized by negative ice cover anomalies. The location and length of the areas of increased (or decreased) chlorophyll a concentrations were consistent with the alternation of water masses. Separate spots of early spring bloom were identified – in coastal waters in the southeastern and southwestern Barents Sea. In late March and early April 2021, maximum chlorophyll a concentrations in coastal waters reached values of about 1 mg·m−3. At the same time, in the Barents Sea and Arctic waters, the maximum content did not exceed 0.20 mg·m−3. The distribution of nutrients corresponded to that for the winter period when the vertical gradients of these parameters were not formed yet. The values of water saturation with oxygen exceeding 100% (to varying degrees throughout the studied area) characterized the activation of the photosynthesis process in the phytoplankton community. Analysis of long-term data showed that the subsequent active spring phytoplankton bloom in years with negative ice cover anomalies occurred already in the second or third decade of April in the Barents Sea water masses of various types – in Arctic, Atlantic, and coastal waters (maximum chlorophyll a concentration reached the value of 5.69 mg·m−3 in Arctic waters). In May, this process covered various types of water masses throughout the Barents Sea (maximum chlorophyll a content was of 5.08–5.77 mg·m−3). In abnormally cold years, the low position of the ice edge in March–April limited the possible area of phytoplankton development, and the active phase of its bloom (according to satellite data) occurred much later, in May. Atlantification of the Barents Sea contributes to the formation of several bloom spots and the distribution of spring bloom over a larger area, which might affect the annual production indicators of the entire pelagic zone.
The effect of hydrogen sulfide loading on the morphometric characteristics of erythroid elements of Anadara kagoshimensis (Tokunaga, 1906) hemolymph was studied experimentally. The work was carried out on adult molluscs with a shell height of 26–38 mm. Molluscs of the control group were kept in an aquarium with oxygen concentration of 7.0–7.1 mg O2·L−1 (normoxia). Molluscs of the experimental group were exposed to hydrogen sulfide loading created by Na2S donor dissolving in water to a final concentration of 6 mg S2−·L−1. A day later, the oxygen level in water amounted to 1.8 mg O2·L−1, and hydrogen sulfide was not detected. Some of molluscs were subjected to repeated hydrogen sulfide loading by Na2S adding up to a final concentration of 9 mg S2−·L−1. By the end of the second day, 1.9 mg S2−·L−1 and 0.03 mg O2·L−1 (trace oxygen concentration) were recorded in water. Under conditions of short-term hydrogen sulfide loading (the first day), the population of A. kagoshimensis erythroid elements became more heterogeneous. In the hemolymph, the content of micro- and macrocytes increased; the number of cells with an altered shape and low content of granular inclusions in the cytoplasm rose. The number of free hematin granules in the hemolymph significantly increased. The mean cell volume (Vc) rose by more than 20%. Exposure to increased concentration of sulfides for two days led to a noticeable decrease in Vc, which is determined by a significant reduction in the population of macrocytes in the hemolymph of molluscs.
The variability of external morphological characters (36 morphometric and 6 meristic ones) of the round goby Neogobius melanostomus (Pallas, 1814) from seven regions of the Sea of Azov–Black Sea Basin is considered: the northwestern and southwestern Black Sea coast of the Crimean Peninsula (the Karkinitsky Bay, Donuzlav Liman, and Streletskaya Bay of Sevastopol), the Kazantip Bay of the Sea of Azov, and the Salgir River in the central Crimean Peninsula. As established, the round goby from different catch regions at the age of 2+…3 has different body sizes: the maximum in individuals from the Streletskaya Bay, SLav (136.2 ± 1.97) mm; the minimum in individuals from the Salgir River, SLav (66.8 ± 2.28) mm. With the Mann–Whitney test, statistically significant differences were found between the samples for most morphometric characters. In terms of meristic characters, there were no differences. The greatest contributors to the discrimination of N. melanostomus samples were morphometric characters related to the location of fins. According to the results of cluster analysis, based on the totality of all the studied characters of the round goby of the Sea of Azov–Black Sea Basin, the samples from the Karkinitsky Bay (Samarchik Bay and Yarylgachskaya Bay, D = 28.6) and from the Bakalskaya Spit water area had the highest similarity. At the level of divergence D = 47.3, groups of the round goby from the Streletskaya Bay and Kazantip Bay were united; then, a sample from the Donuzlav Liman adjoined them at the level D = 215. The sample from the Salgir River had the most isolated position: the level of divergence was about 475. As found according to the discriminant analysis, the round goby from the Sea of Azov–Black Sea Basin was differentiated into at least three spatial groups: the first one, from the western coast of the Crimean Peninsula (the Karkinitsky Bay and Donuzlav Liman) and the Sevastopol area (the Streletskaya Bay); the second one, from the Kazantip Bay (the Sea of Azov); and the third one, from the Salgir River. The following characters made the greatest contribution to the discrimination of spatial groupings (with the correlation coefficient between characters and coordinate values along the second canonical axis being higher than 0.75): maximum body depth, caudal peduncle depth and width, predorsal and prepelvic distances, and width of pectoral and pelvic fin base. The revealed heterogeneity shows a high paratypical variability of morphometric characters; under different environmental conditions, individuals of the same species form a specific phenotype.
Nonylphenol (NP) is a ubiquitous environmental pollutant of major concern due to its toxicity to hydrobionts, animals, and humans. Moreover, NP is known as an endocrine disruptor. The aim of this study is to isolate from bottom sediments sampled in the southern Gulf of Finland (the Baltic Sea) and identify a highly-efficient NP-degrading bacterial strain and to analyze its NP-degrading capacity at different levels of temperature, initial pH, dissolved oxygen concentrations, and initial NP content. The isolated strain F8 was identified by phenotypic traits using standard methods and by Sanger sequencing of a fragment of the 16S rRNA gene sequence (rrs). NP content was determined by high-performance liquid chromatography. The novel NP-degrading bacterium Raoultella planticola F8 was isolated from the bottom sediments sampled in the Gulf of Finland. R. planticola F8 isolate was deposited in the Russian Collection of Agricultural Microorganisms (RCAM), All-Russia Research Institute for Agricultural Microbiology, as the strain RCAM 05450. The rrs sequence of the F8 isolate was deposited in the GenBank database (No. OL831016). This strain is highly efficient for NP degradation in aerobic conditions at different NP concentrations (up to 900 mg·L−1), in the temperature range of +5…+35 °C, the initial pH range of 5–9, and the dissolved oxygen concentration range of 0.8–2.46 mg·L−1. This is the first study to demonstrate the ability of R. planticola to degrade NP. Results of this investigation provide useful information for R. planticola F8 application in bioremediation processes.
The work is devoted to problems of mutual adaptation of two invasive commercial crab species, the red king crab Paralithodes camtschaticus and the snow crab Chionoecetes opilio, and the recipient ecosystem of the Barents Sea. Data on the distribution of megabenthic communities obtained for 2006–2020 are provided. The dynamics of invasive crab populations is analyzed, and related changes that occurred in the Barents Sea bottom communities during this period are studied. Mechanisms of the impact of crab species on bottom communities and prospects for their colonization of the Barents Sea are discussed. The research is based on the results of quantitative and taxonomic analysis of bycatch in 6,010 by-catches with a Campelen 1800 trawl performed in the Barents Sea in 2006–2020 during the joint Russian–Norwegian ecosystem survey on RV of the Polar branch of VNIRO and the Institute of Marine Research. The expansion of the range and increase in abundance of the red king crab since the early 1990s led to its colonization of the vast water area of the southern Barents Sea. In 2006–2010, this species dominated in megabenthic communities around the Murmansk Rise and Kaninskaya Bank. In 2016–2020, the red king crab spread north and east – up to the Kolguev Island and the southern slope of the Goose Bank. An increase in abundance of the snow crab resulted in its colonization of a huge area in the Barents Sea: from the Pechora Sea to the Franz Josef Land archipelago and from the Novaya Zemlya archipelago to the Spitsbergen archipelago. In 2006–2010, the snow crab abundance started to increase in the Novaya Zemlya archipelago area; there, it was a subdominant species in communities of soft sediments of the Goose Bank. In 2011–2015, the snow crab began to dominate in communities of the Goose and Novaya Zemlya banks and the northern Central Bank. At the same time, it continued to increase its role as a subdominant species in almost all megabenthic communities near the Novaya Zemlya archipelago. Later, in 2016–2020, this species dominated in benthic communities on the boundary with the Kara Sea between the Novaya Zemlya and Franz Josef Land archipelagos, on the slopes of the Novaya Zemlya Bank, near the Central Bank, and in the Southern Novaya Zemlya Trench. Its range increased and covered the area from the Franz Josef Land and Novaya Zemlya archipelagos to the Perseus Bank in the west and to the Pechora Sea in the south. As shown, under current climatic conditions, the red king crab will remain part of megabenthic communities in the southeastern Barents Sea. The snow crab will continue to migrate from the east to the western Barents Sea, up to the Spitsbergen archipelago, where similar benthic communities exist; in case of colder weather, its migration will occur faster. A scenario is possible in which shallow waters of the Spitsbergen archipelago will be a new reproductive center of the snow crab population in the Barents Sea, along with the current center near the Novaya Zemlya archipelago.
The results of the experiment on the use of a Labfors 5 Lux LED flat panel bioreactor (Infors HT, Switzerland) for Tisochrysis lutea (Haptophyta) cultivation are presented. During the three-week study, growth and size structure of the microalga population were assessed, and the content of chlorophyll a, carotenoids, and neutral lipids was estimated. The highest cell abundance, 5.3 × 104 cells·mL−1, was recorded at the end of the experiment, on the 21st day. An increase in the proportion of 4–6-μm cells was registered on the 11th day. The maximum accumulation of carotenoids occurred on the 18th day (3.3 mg·L−1), and neutral lipids (Nile Red fluorescence was of 5.3 × 106), on the 14th–21st day. As revealed, Labfors 5 Lux LED flat panel bioreactor can be successfully used for cultivation of the microalga T. lutea.
Features of stress reaction formation were studied in cells of the green alga Acrosiphonia arcta under the effect of diesel fuel emulsion. Changes in indicators of oxidative stress (concentration of hydrogen peroxide and accumulation of products of lipid peroxidation) were analyzed; activity of antioxidant enzymes, intensity of photosynthesis, and condition of cells were investigated. As shown, during the first day of exposure to the toxicant, plasmolysis and disruption of the chloroplast structure occur in cells. The stress reaction develops in stages. At the first stage, the amount of hydrogen peroxide increases, the concentration of products of lipid peroxidation changes, and the activity of superoxide dismutase rises. At the second stage, catalase activity increases. By the end of the first day of exposure, against the backdrop of a drop in catalase activity, peroxidase activity rises (the third stage). The intensity of photosynthesis decreases by the end of the experiment. As suggested, under the effect of diesel fuel emulsion, the daily dynamics of the biological cycles of a number of enzymes may be disrupted.
Stylotheristus paramutilus sp. nov. from bottom sediments sampled in shallow-water and deep-sea habitats in the Black Sea is described and illustrated. The new species is characterized by well-developed lip region; 12 setiform cephalic sensilla in female and 16 in male; cervical setae present; spicules 0.6–0.9 anal body diameters long and expanded proximally; gubernaculum plate-like slightly curved; conico-cylindrical tail of 4.5–5.8 anal body diameters (except for one male with it equal to 12.9 anal body diameters); and 3 terminal setae. The present study provides the first Stylotheristus species record in the Black Sea. S. paramutilus sp. nov. is characterized by a wide spatial and bathymetrical (2–250-m depths) distribution in the Crimea region and the Istanbul Strait’s (Bosphorus) outlet area of the Black Sea. However, in future, molecular analysis is required to confirm the identity of these specimens from different Black Sea habitats.
Климатические изменения в гидрологическом режиме Чёрного моря, отмечаемые с 1990-х гг., отразились на состоянии эпипелагических комплексов морских организмов, прежде всего на сезонной изменчивости их биологических циклов. Это оказало существенное влияние на фенологию нереста природных популяций рыб, видовое разнообразие и пространственное распределение ихтиопланктона, а также на устоявшиеся трофические взаимоотношения в планктонном сообществе. В конечном итоге характер взаимодействия между различными звеньями трофической цепи в эпипелагических комплексах, их сезонная и межгодовая изменчивость влияют на эффективность нереста рыб, прежде всего массовых промысловых видов, и в значительной степени определяют успех пополнения их будущих поколений. С целью изучения видового состава, численности и пространственного распределения ихтиопланктона в октябре 2016 г. (89-й рейс НИС «Профессор Водяницкий», 30 сентября — 19 октября) были проведены исследования в шельфовых и открытых водах Чёрного моря у Крымского полуострова, проанализированы не только икра и личинки рыб, но и биомасса мезо- и макропланктона. Пробы ихтио- и макропланктона отбирали сетью Богорова — Расса (площадь входного отверстия — 0,5 м²; ячея — 300 мкм) методом тотальных вертикальных ловов от дна до поверхности моря в области шельфа и от нижней границы кислородной зоны до поверхности моря в глубоководной части. Ихтиопланктон фиксировали 4%-ным раствором формалина и анализировали позже под микроскопом, определяя таксономический состав организмов и по возможности — наличие и состав пищи в кишечниках личинок рыб. Проанализированы данные о видовом составе и пространственном распределении ихтио-, мезо- и макропланктона, а также о питании личинок рыб Чёрного моря у Крымского полуострова в октябре 2016 г. Период съёмки соответствовал начальной фазе осеннего гидрологического сезона. Ихтиопланктон был представлен икрой и личинками 9 видов тепловодных и 6 видов умеренноводных рыб. Средняя численность икры рыб составляла 2,92, а личинок — 3,56 экз.·м−2. Низкая доля (30 %) мёртвой икры тепловодной хамсы Engraulis encrasicolus, а также наличие её разноразмерных личинок в море свидетельствовали о продолжении результативного нереста. Биомасса зоопланктона возрастала в направлении от шельфа к глубоководным районам. Мелкоразмерные фракции планктонных организмов преобладали на шельфе, обеспечивая здесь лучшие кормовые условия для выживания личинок рыб. Несмотря на значительную биомассу желетелых-планктофагов в октябре 2016 г., их влияние на ихтиопланктонные комплексы Чёрного моря, по-видимому, оставалось несущественным.
Проведён анализ пространственной и временнόй изменчивости биомассы фитопланктона в поверхностном слое Чёрного моря за 18-летний период и оценено влияние основных течений в море на пространственную и временнýю динамику биомассы фототрофного фитопланктона. Использованы регулярные многолетние данные концентрации хлорофилла, полученные по спутниковым наблюдениям с помощью приборов SeaWiFS и MODIS-Aqua/Terra за период с 1998 по 2015 г. в Чёрном море. Оценена роль макро- и микроциркуляций в пространственно-временнόй вариабельности биомассы фитопланктона. Усиление ветровой активности и снижение температуры воды с октября по март, приводящие к увеличению глубины перемешивания верхнего слоя и интенсивности основных синоптических циркуляций, становятся существенным фактором, который способствует возникновению зимнего и весеннего цветения фитопланктона. Выявлено, что понижение средней температуры воды в холодный сезон до +7…+8 °C на протяжении более чем полутора месяцев в глубоководной зоне приводит к интенсивному развитию биомассы весной. Установлено, что средняя биомасса фитопланктона за 18-летний период в западном и восточном циклонических круговоротах составляет (38,0 ± 17,8) и (37,7 ± 16,8) мг C·м−3 соответственно, в Батумском антициклоне — (38,2 ± 18,0) мг C·м−3. Основное черноморское течение, как правило, переносит фитопланктон, образовавшийся у шельфовой зоны, вдоль береговой линии, мало смешиваясь с водами глубоководной акватории. В циклонических круговоротах зимне-весеннее цветение фитопланктона наблюдается в среднем на протяжении полутора месяцев. Интенсивное цветение в районе стока северо-западных рек, регистрируемое в мае — июне, распространяется до пролива Босфор, тогда как в холодный сезон может в виде микровихрей проникать в глубоководную зону. В зимние и весенние месяцы Севастопольский антициклонический вихрь выделялся как отдельная зона в развитии биомассы. Роль антропогенной нагрузки наиболее существенна в прибрежной зоне. При этом влияние прибрежных вод на глубоководную зону в некоторой степени возможно поздней осенью и зимой.
Биолюминесценция — существенный элемент функционирования пелагического сообщества, что связано с важнейшей экологической ролью света в жизни гидробионтов, в том числе в формировании их пространственной неоднородности. Свечение морских гидробионтов — это проявление их жизнедеятельности в форме электромагнитного излучения в видимой области спектра, кинетические закономерности которого тесно связаны с механизмом порождающих их химических реакций и процессов метаболизма. Глобальное потепление, охватившее и Атлантический сектор Антарктики, вызвало серьёзные структурно-функциональные изменения пелагического сообщества, которые отражаются на морской биолюминесценции — экспрессивном показателе состояния среды. Целью работы было изучить возможность применения метода многократного вертикального зондирования гидробиофизическим комплексом «Сальпа-М» с одновременной фиксацией биофизических и гидрологических параметров на одной станции для исследования структуры и протяжённости полей свечения антарктических вод. В статье представлены метод изучения структурных характеристик биолюминесценции и материалы, полученные во время 79-й антарктической экспедиции на НИС «Академик Мстислав Келдыш». Суть метода зондирования состоит в подъёме (или опускании) батифотометра «Сальпа-М» с постоянной скоростью в заданном слое [обычно это верхний продуктивный (0–200 м) или фотический (0–100 м) слой] в дрейфе судна. Планктонные биолюминесценты, вносящие основной вклад в формирование биолюминесцентного потенциала пелагиали, высвечиваются, как правило, только при раздражении. Именно поэтому движущийся с постоянной скоростью батифотометр создаёт стандартный уровень их механического раздражения, что позволяет корректно сравнивать результаты измерений вертикальной структуры поля биолюминесценции, выполняемых в разных регионах и при различных погодных условиях (качка, ветровой снос и т. д.). В работе представлен набор данных об интегральном биолюминесцентном сигнале на разных горизонтах. На 18 гидрографических станциях в исследуемой акватории Атлантического сектора Антарктики были получены первичные данные интенсивности биолюминесценции, значений температуры, электропроводности и фотосинтетически активной радиации. В статье рассмотрен важный вопрос, который связан с изменением биолюминесценции морской воды в Атлантическом секторе Антарктики, изученной методом вертикального зондирования на разных уровнях с помощью биолюминесцентного зонда. При исследовании биолюминесценции выполняли определение вертикальной изменчивости свечения в верхнем продуктивном слое в связи с особенностями распределения планктона. В результате было установлено, что свечение антарктических вод в фотическом слое этого района происходит в пределах от 8,4 × 10−12 до 104,42 × 10−12 Вт·см−2·л−1. Пики биолюминесценции (до 104 × 10−12 Вт·см−2·л−1) фиксировали под термоклином на глубине 45 м в зонах концентрации сальп Salpa thompsoni Foxton, 1961 вблизи гидрологического фронта, на расстоянии около 6–7 миль по обе стороны от него. Показано, что метод вертикального зондирования в антарктических водах даёт возможность экспресс-регистрации полей и структуры скопления светящихся организмов.
Цель исследования — выявить закономерные изменения в обилии, видовом разнообразии и структуре сообществ метазойного микрозоопланктона (ММ) в градиентных условиях морского прибрежья на относительно небольших пространственных масштабах. Актуальность работы определяется малочисленностью подобных исследований, позволяющих опосредованно оценить степень антропогенного воздействия на морскую биоту и установить трофический статус локальных акваторий с помощью индексов видового разнообразия. Проанализированы три акватории прибрежья города Севастополя: открытое взморье, устье Севастопольской бухты и внутренняя её часть. Локализация станций отбора проб отражает градиент условий среды, характеризующийся разной степенью воздействия на биоту природных и антропогенных факторов. Исследования проведены в летний и осенний периоды года. Пробы ММ отбирали из трёх горизонтов водного столба — поверхностного, 0–5-метрового и 0–10-метрового слоёв. В открытом взморье и устье бухты численность ММ по вертикали была более выравненной, тогда как в глубине бухты различия между слоями могли достигать 5–700 раз. Максимальная численность ММ (1837,1 тыс. экз.·м−3) отмечена в начале августа в поверхностном слое во внутренней части бухты. С конца лета происходило снижение обилия во всех исследованных акваториях. Видовое разнообразие сообщества ММ, оценённое с помощью индексов Шеннона, Симпсона, Пиелу и др., уменьшалось в направлении от открытого взморья вглубь бухты. Эта закономерность сохранялась в оба сезона. Наиболее информативными оказались индекс Шеннона, индекс полидоминантности Симпсона и индекс выравненности Пиелу. Они хорошо отражали как сезонные изменения видового разнообразия, так и направленность изменений в градиенте трофности локальных акваторий бухты. С помощью многомерного анализа выявлены случаи существенной трансформации в структуре сообщества ММ придонного слоя вод в глубине бухты. Основной вероятной причиной этих локальных изменений является возникновение в загрязнённых участках бухты гипоксийных условий в нижних горизонтах вод, приводящее к деградации численности и видового состава исследуемого зоопланктонного сообщества.
