T. Yu. Orlova

Distribution of DTX-3 in edible and non-edible parts of Crenomytilus grayanus from the Sea of Japan.

Seasonal dynamics and the distribution of dinophysistoxin-3 (DTX-3) in organs of mussel Crenomytilus grayanus, collected in 2013 in Peter the Great Bay, Sea of Japan, were determined. Active toxin forms (OA, DTX-1/2) concentrated in digestive glands (60-80%), whereas non-active 7-O-acyl derivatives (DTX-3) were more abundant in edible soft tissues (more than 80%). Possible mechanism of fast removing of DTX-3 from the digestive gland and accumulation of DTX-3 in the soft tissues is supposed.

Resting stages of microalgae in recent marine sediments of Peter the Great Bay, Sea of Japan

Data on the qualitative and quantitative composition of resting stages of planktonic microalgae in recent marine sediments of Peter the Great Bay (Sea of Japan) over the period 2000–2007 are presented. A total of sixty one morphological forms of resting stages represented by dinoflagellate and raphidophyte cysts and diatom spores and resting cells were recorded in the sediment samples. This study revealed cysts of the potentially toxic species Alexandrium tamarense, A. cf. minutum, Alexandrium sp., Gymnodinium catenatum (PSP toxin producers), and Protoceratium reticulatum (yessotoxin producer); resting cells of Pseudo-nitzschia sp. (potential producer of domoic acid); and cysts of bloom-forming species Cochlodinium cf. polykrikoides and Heterosigma cf. akashiwo.

Morphology and Ecology of the Species of the Genus Pseudo-nitzschia (Bacillariophyta) from Peter the Great Bay, Sea of Japan

Phytoplankton studies in Peter the Great Bay (Sea of Japan) revealed three species of the genus Pseudo-nitzschia H. Perag. in H. et M. Peragallo, namely, P. pungens (Grun. ex Cl.) Hasle; P. multiseries (Grun.) Hasle, and P. pseudodelicatissima Hasle. Mass blooms of P. pungens and P. multiseries were registered in Amurskii Bay in June 1992. The maximum density (11 million cell/liter) was registered at the water surface after heavy rainfall. A short-term outburst of the density of P. pseudodelicatissima (2.7 million cells/liter) was registered in Amurskii Bay in November 1997. We present morphological descriptions of all the species from the results of light and electron microscopy and discuss possible reasons favoring their mass development in Peter the Great Bay.

Flora of planktonic microalgae of Amursky Bay, Sea of Japan

Long-term studies of the species composition of phytoplankton in Amursky Bay (Sea of Japan) carried out during the period from 1991 to 2006 revealed a total of 357 species of planktonic microalgae from eight divisions: Cyanophyta (8 species), Chrysophyta (8), Bacillariophyta (157), Cryptophyta (5), Dinophyta (143), Raphidophyta (3), Euglenophyta (11), and Chlorophyta (22 species). An annotated checklist of species is presented. In comparison with the late 1960s and early 1970s, the species richness of phytoplankton increased markedly; a greater number of bloom-forming species was recorded.

Toxic and harmful algae in the coastal waters of Russia

Toxic algal species of marine and brackish-water plankton, as well as nontoxic microalgae, which are capable of initiating harmful blooms, cause a detriment to human health (seafood poisoning) and often lead to a total crisis of coastal water ecosystems. The Russian coastal waters are inhabited by dozens of toxic and bloom-causing algal species, their toxins are accumulated in the tissues of edible mollusks, and there have been incidents of human poisonings and marine fauna mortality due to these blooms. An analysis of the current situation concerning the problem of toxic algae and harmful blooms of nontoxic species in the seas of Russia provides evidence that it is necessary to create a system of compulsory governmental monitoring of the exploited marine areas to serve as the basis of ecological safety control in the exploitation of the biological resources of the Russian Federation, as well to introduce compulsory sanitary control of diarrheic, paralytic, and amnesic phycotoxins. The compiled summary of algal toxic and potentially toxic species met in the European and Far Eastern seas of Russia is given with notes on their toxicity type and its manifestations.

A “Bloom” in the Water of Amursky Bay (Sea of Japan) Caused by the Dinoflagellate Oxyrrhis marina Dujardin, 1841

A “bloom” in the water of Amursky Bay (Sea of Japan) caused by the dinoflagellate Oxyrrhis marina Dujardin, 1841 was recorded for the first time. The highest density of this species in the “bloom” area was 443.3 million cells/liter. The abundant development of microalga was observed from July to September 2002 at a water temperature of 17–24.5°C and a salinity of 7–18‰. Changes in the density of O. marina and other species of phytoplankton during the “bloom” period are analyzed. Possible reasons for the “blooms” of O. marina in Amursky Bay are discussed.

Seasonal Dynamics of the Diatoms of the Genus Chaetoceros Ehrenberg in Amursky Bay (Sea of Japan)

The qualitative and quantitative composition of the Chaetoceros Ehr. species was studied in Amursky Bay (Sea of Japan) from January 1996 until May 1998. In all, 30 species, 1 variety, and 1 form of this genus were registered. The species Chaetoceros occurred in plankton throughout the year at a water temperature of –1.8–25°C and a salinity of 11–35‰. The numbers of Chaetoceros species varied between 100 and 1u2009071u2009000 cells/l, and the biomass varied between 0.9 × 10–3 and 3.3 g/m3. The numbers were maximum in summer and minimum in the beginning of spring. The Chaetoceros species comprised 45–70 and 5–18% (winter), 68–98 and 65–95% (spring), 50% (summer), and 20% (autumn) of the total phytoplankton numbers and biomass. Six dominant species and 1 variety of Chaetoceros were found. Seasonal complexes formed by the Chaetoceros species were identified and described.

Morphology and ecology of the bloom-forming diatom Chaetoceros contortus from Peter the Great Bay, Sea of Japan

The morphology of the marine planktonic diatom Chaetoceros contortus Schütt from the Sea of Japan is described using light and electron microscopy. Because of morphological similarity, C. contortus was previously synonymized with the close species C. compressus Lauder by Gran and Yendo [22]. Abundant development of C. contortus was observed in 1997 in Amursky Bay (Sea of Japan). This species reached a maximum density of up to 1.3 × 106 cells/liter near the water surface in mid May 1997 in the period of water-column stratification.

Genus Alexandrium Halim, 1960 (Dinophyta) from the Pacific coast of Russia: Species composition, distribution, and dynamics

At present 8 species of Alexandrium genus have been found in seas and adjacent waters of Russia: A. acatenella, A. catenella, A. insuetum, A. margalefii, A. ostenfeldii, A. pseudogonyaulax, A. tamarense, and A. tamutum. The distribution and population density of Alexandrium species varied within the surveyed area of the Pacific: in the Sea of Japan and Sea of Okhotsk, 7 species were recorded; 3 species were recorded along the Pacific coast of Kamchatka; and 2 species were found in the Bering Sea. A. tamarense was the most widespread and abundant species over the area. A. insuetum was recorded only in the Sea of Japan, and A. catenella, in the Sea of Okhotsk (Terpeniya Bay). The highest concentration of Alexandrium spp. (2–7 million cells/l) was recorded along the Pacific coast of Kamchatka and in the Bering Sea; in the Sea of Okhotsk, a rather high concentration (51000 cells/l) was registered in Aniva Bay; in the Sea of Japan, the highest concentration was recorded in Peter the Great Bay (6000 cells/l). The distribution of cysts (spores) in surface sediments of the Pacific coast of Russia as a whole reflected the pattern of distribution of vegetative cells of Alexandrium. Cysts of Alexandrium cf. tamarense prevailed all over the area, with the maximum concentration along the Pacific coast of Kamchatka. Beyond that type of cysts, insignificant numbers of cysts of Alexandrium cf. minutum were recorded in Peter the Great Bay and Aniva Bay. Analysis of seasonal dynamics revealed that cells of Alexandrium spp. occurred in Peter the Great Bay from June up to September, and along the Pacific coast of Kamchatka from April to October. In the first region, the maximum density was recorded in August; it was provided by A. pseudogonyaulax (59% of the total density of Alexandrium), A. tamarense (35%), and A. insuetum (6%). In the second region, it was recorded in July, thanks only to development of A. tamarense.

Species Structure of Plankton Microalgae on the Coast of the Sea of Okhotsk on Sakhalin Island

The results of long-term studies of the species structure of microalgae plankton of the coast of the Sea of Okhotsk of Sakhalin Island were summarized. There were 227 species and 4 intraspecific taxa attributed to 8 divisions. The greatest number of species was represented by the divisions Bacillariophyta (112 species and 3 intraspecific taxa) and Dinophyta (96 and 1 respectively). For the first time 5 diatom, 4 dinoflagellate, and 1 euglenophyte species were recorded for the Sea of Okhotsk.