Marine Biological Journal

Morphometric variability in the round goby Neogobius melanostomus (Pallas, 1814) (Actinopterygii, Gobiidae) of the Sea of Azov–Black Sea Basin

R. Belogurova — Fri, 22 Mar 2024 00:00:00 +0000

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, SL_av (136.2 ± 1.97) mm; the minimum in individuals from the Salgir River, SL_av (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 biodegradation by the bacterium Raoultella planticola strain F8 isolated from the sediment of the Gulf of Finland, the Baltic Sea

T. Zaytseva, V. Safronova, A. Russu, I. Kuzikova, N. Medvedeva — Fri, 22 Mar 2024 00:00:00 +0000

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.

Impact of the red king crab and the snow crab on the Barents Sea megabenthic communities

D. Zakharov, I. Manushin, L. Jørgensen, N. Strelkova — Fri, 22 Mar 2024 00:00:00 +0000

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.

Localization of phytoplankton early spring bloom spots in the pelagic zone of the Barents Sea

Fri, 22 Mar 2024 00:00:00 +0000

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.

Experience of growing the microalga Tisochrysis lutea (Haptophyta) under conditions of a Labfors bioreactor for the production of carotenoids and neutral lipids

Zh. Markina, A. Zinov, T. Orlova — Fri, 22 Mar 2024 00:00:00 +0000

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 21^st day. An increase in the proportion of 4–6-μm cells was registered on the 11^th day. The maximum accumulation of carotenoids occurred on the 18^th day (3.3 mg·L⁻¹), and neutral lipids (Nile Red fluorescence was of 5.3 × 10⁶), on the 14^th–21^st day. As revealed, Labfors 5 Lux LED flat panel bioreactor can be successfully used for cultivation of the microalga T. lutea.

Stylotheristus paramutilus sp. nov. (Nematoda: Xyalidae), a new nematode species from the Black Sea

T. Revkova, N. Sergeeva — Fri, 22 Mar 2024 00:00:00 +0000

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.

Analysis of physiological and biochemical parameters of Acrosiphonia arcta (Dillwyn) Gain cells at the early stage of stress reaction formation under the effect of diesel fuel emulsion

I. Ryzhik, D. Salakhov, M. Makarov, M. Menshakova — Fri, 22 Mar 2024 00:00:00 +0000

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.

Morphometric characteristics of erythroid elements of Anadara kagoshimensis (Tokunaga, 1906) hemolymph under conditions of hydrogen sulfide loading

A. Soldatov, V. Rychkova, T. Kukhareva — Fri, 22 Mar 2024 00:00:00 +0000

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 (V_c) rose by more than 20%. Exposure to increased concentration of sulfides for two days led to a noticeable decrease in V_c, which is determined by a significant reduction in the population of macrocytes in the hemolymph of molluscs.

Marine algal flora of the southern islands of Japan

E. Titlyanov, T. Titlyanova, O. Belous, M. Tokeshi — Fri, 22 Mar 2024 00:00:00 +0000

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.

On the anniversary of Ilkham Khayam ogly Alekperov, D. Sc., Professor, corresponding member of the Azerbaijan NAS

Fri, 22 Mar 2024 00:00:00 +0000

On 20 November, 2023, Ilkham Khayam ogly Alekperov celebrated his 75ᵗʰ birthday – D. Sc., Professor, and corresponding member of the Azerbaijan National Academy of Sciences. I. Kh. Alekperov is a famous protistologist who heads the laboratory of protozoology at the Institute of Zoology of the Azerbaijan National Academy of Sciences. He is the author and co-author of 4 monographs and more than 190 scientific articles and serves on editorial boards of 7 scientific journals.