M. S. Selina

Morphogenetic and toxin composition variability of Alexandrium tamarense (Dinophyceae) from the east coast of Russia

T.Y. Orlova, M.S. Selina, E.L. Lilly, D.M. Kulis and D.M. Anderson. 2007. Morphogenetic and toxin composition variability of Alexandrium tamarense (Dinophyceae) from the east coast of Russia. Phycologia 46: 534–548. DOI: 10.2216/06-17.1 Twenty-seven clones were established from elongate Alexandrium sp. cysts collected in six regions along the Russian Pacific coast. All isolates were identified as Alexandrium tamarense via detailed epifluoresence microscopy of thecal plates. Morphological differences of both cultured and wild cells from the study regions mainly occurred in the shape of the cell (length/width ratio), degree of development of the sulcal list, and the shape of the posterior sulcal (S.p.) and second antapical (2″″) plates. Cells were divided into two cell types: ‘short’ (isodiametrical or wide) and ‘tall’. Each cell type exhibits specific features of tabulation, mainly the shape of the S.p. and 2″″ plates and was dominant in each particular region of the study. The short type, with a wide S.p. and reduced length in the dorsoventral 2″″ plates, was characteristic of A. tamarense from Primorye and southern Sakhalin Island. The tall cells, i.e., with cell length exceeding width, and having and elongate S.p. and dorsoventrally elongate 2″″ plates, prevailed in Avachinskaya Guba Inlet and in the Bering Sea. The differences reported here between the two types are within the range of morphological variability of A. tamarense sensu Balech, 1995. The D1–D2 fragment of the large subunit nuclear ribosomal DNA was analyzed for 24 clones. Alexandrium tamarense from the Russian Pacific coast compose three genetically distinct populations that correspond to the Japanese temperate Asian, eastern North American, and western North American ribotypes of the ‘tamarensis’ complex. The presence and distribution of eastern and western North American ribotypes along the Russian Pacific coast suggest that dispersion to the temperate Asian region occurred long ago via natural currents and processes, and not through human-mediated introductions, as has been proposed. No strict correlation was observed between different morphological types of cells and ribotypes. High-performance liquid chromatography toxin analyses showed that all isolates were toxic and demonstrated variability in toxin content and composition among different populations. These data document the significant and previously uncharacterized risk of shellfish contamination with paralytic shellfish poisoning toxins from blooms of A. tamarense in Russian marine waters.

Species composition and morphology of dinoflagellates (Dinophyta) of epiphytic assemblages of Peter the Great Bay in the Sea of Japan

The species composition of dinoflagellates in epiphytic assemblages at 0.5–3 m depth in Sobol Bight (Peter the Great Bay in the Sea of Japan) was examined in August–October 2006. A total of 29 dinoflagellate species were found. Planktonic species contributed 54% and benthic and benthic-planktonic species together contributed 36% to the total number of dinoflagellate species. The latter group was represented by 13 species of eight genera, including five potentially toxic species. The occurrences of Cabra matta Murray et Patterson, Ostreopsis cf. siamensis Schmidt, O. cf. ovata Fukuyo, and Prorocentrum fukuyoi Murray et Nagahama are recorded for the seas of Russia for the first time. Amphidinium carterae Hulburt is the first record for the Far Eastern seas and Pseudothecadinium campbellii Hoppenrath et Selina for the Sea of Japan. Morphological descriptions of dinoflagellates that are new records for the study region or potentially toxic species are given. One to ten species of benthic and benthic-planktonic dinoflagellates per macrophyte were found. In all, 13 species of red algae, 9 brown algae, 3 green algae, and 1 species of seagrass were examined. O. cf. ovata, O. cf. siamensis, and P. fukuyoi were the most frequent and abundant.

Taxonomy, phylogeny, biogeography, and ecology of Sabulodinium undulatum (Dinophyceae), including an emended description of the species

Samples of Sabulodinium undulatum Saunders et Dodge, the type species of the monospecific genus, were collected and characterized from Germany, Russia, Japan and Canada. This species has a laterally flattened, oval cell with a truncated apex and a dorsally pointing small episome. The dorsal margin of the hyposome has an undulating shape. A dorsal spine and/or antapical spine are sometimes present. The specimens of this heterotrophic species are 27.5–42.5 μm long and 18.5–36.0 μm wide, and have a theca with the plate arrangement apical pore complex (APC) 5′ 1a 6″ 5c 4s 6′′′ 1′′′′. The shape of the dorsal theca is variable. The species distribution seems to be restricted to northern temperate regions. Sabulodinium undulatum occurred in all sandy eulittoral areas throughout the year and was also present in sandy sublittoral and supralittoral (beach) samples. The species can tolerate a broad range of temperatures and salinities. Sabulodinium occurred from −2.0 to +24.3°C and 4–35 salinity. It is likely that the observed variability in morphology and habitat reflect several varieties. We propose to establish three varieties within the species, namely S. undulatum var. undulatum, S. undulatum var. glabromarginatum, and S. undulatum var. monospinum. The systematic position of Sabulodinium is discussed in the context of comparative morphological and molecular phylogenetic data.

Morphology of Sinophysis minima sp. nov. and three Sinophysis species (Dinophyceae, Dinophysiales) from the Sea of Japan

Four sand‐dwelling species of the marine dinoflagellate genus Sinophysis, including one new species, have been examined from intertidal and subtidal sand, from the Sea of Japan. The morphological features of these species were observed by light and scanning electron microscopy. Sinophysis minima sp. nov. is flattened laterally and is 17.5–35.0 μm in length and 15.0–27.5 μm in depth, with a length/depth ratio of 1.1–1.4, an epitheca depth of 5.0–7.5 μm, and a sulcus length of about three‐quarters the hypotheca length. Sinophysis ebriola (Herdman) Balech, Sinophysis grandis Hoppenrath and Sinophysis stenosoma Hoppenrath were recorded for the first time in the seas of Russia. Sinophysis stenosoma is the most common species in the Sea of Japan. All species usually occurred together in the region investigated. Additional information on the known species is provided.

Morphology and ecology of the bloom-forming planktonic diatom Chaetoceros salsugineus Takano in the Sea of Japan

The morphology of Chaetoceros salsugineus Takano is described using both light and electron microscopy. This species possesses typical characteristics of the subgenus Hyalochaete. Our investigations show that intercalary valves having processes are actually terminal valves, in the area of contact of which the colony disintegrates into separate short chains. Chaetoceros salsugineus occurred annually in the summer period and was abundant during the summer bloom of phytoplankton. Maximum densities (up to 12 millions cells L −1 ) were recorded near the water surface after heavy rains when stratification of the water column occurs. Some taxonomic and autoecological questions are discussed

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.

Pseudothecadinium campbellii gen. nov. et sp. nov. (Dinophyceae), a phototrophic, thecate, marine planktonic species found in the Sea of Okhotsk, Russia

M. Hoppenrath and M. Selina. 2006. Pseudothecadinium campbellii gen. nov. et sp. nov. (Dinophyceae), a phototrophic, thecate, marine planktonic species found in the Sea of Okhotsk, Russia. Phycologia 45: 260–269. DOI: 10.2216/05-23.1 A new marine planktonic dinoflagellate is described from light and scanning electron microscopical observations of specimens from the Sea of Okhotsk, Russia. Pseudothecadinium campbellii Hoppenrath & Selina gen. and sp. nov. is 36.9–52.5 μm long, 31.8–45.0 μm deep, ovoid in lateral cell view, laterally flattened, with a descending cingulum, displaced about four to six cingular widths, thecate, with the plate formula Po 4′ 2a 4″ 4c 5(?)s 5′″ 1″″ and it contains chloroplasts. Thecal plates are smooth with scattered pores, there is a distinctive second anterior intercalary plate with a ‘ventral pore’, the precingular plate series is incomplete and the antapical cell contour is oblique when seen in ventral view. The plate pattern and the plate arrangement differ from all described dinoflagellate genera, but is most similar to Thecadinium and Thecadiniopsis.

Morphology and molecular phylogeny of Amphidiniopsis rotundata sp. nov. (Peridiniales, Dinophyceae), a benthic marine dinoflagellate

Hoppenrath M., Selina M., Yamaguchi A. and Leander B. 2012. Morphology and molecular phylogeny of Amphidiniopsis rotundata sp. nov. (Peridiniales, Dinophyceae), a benthic marine dinoflagellate. Phycologia 51: 157–167. DOI: 10.2216/11-35.1 A new dinoflagellate species within the benthic, heterotrophic, and thecate genus Amphidiniopsis was discovered, independently, in sediment samples taken on opposite sides of the Pacific Ocean: (1) the Vancouver area, Canada, and (2) Vostok Bay, the Sea of Japan, Russia. The cell morphology was characterized using light and scanning electron microscopy, and the phylogenetic position of this species was inferred from small-subunit ribosomal DNA sequences. The thecal plate pattern [formula: apical pore complex 4′ 3a 7″ 5c 5(6)s 5‴ 2‴′] and ornamentation, as well as the general cell shape without an apical hook or posterior spines, demonstrated that this taxon is different from all other described species within the genus. Amphidiniopsis rotundata sp. nov. was dorsoventrally flattened, 24.5–38.5 µm long, 22.6–32.5 µm wide. The sulcus was characteristically curved and shifted to the left of the ventral side of the cell. This work presents the first molecular study including a representative of the genus Amphidiniopsis, and led us to propose a new combination, Amphidiniopsis dragescoi comb. nov. (formerly Thecadinium dragescoi), and also suggests a close relationship between Amphidiniopsis, Herdmania (another benthic genus), and Archaeperidinium minutum (a planktonic species).

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.