Effects of environmental variation and spatial distance on Bacteria,Archaea and viruses in sub-polar and arctic waters

We investigated the influence of environmental parameters and spatial distance on bacterial, archaeal and viral community composition from 13 sites along a 3200-km long voyage from Halifax to Kugluktuk (Canada) through the Labrador Sea, Baffin Bay and the Arctic Archipelago. Variation partitioning was used to disentangle the effects of environmental parameters, spatial distance and spatially correlated environmental parameters on prokaryotic and viral communities. Viral and prokaryotic community composition were related in the Labrador Sea, but were independent of each other in Baffin Bay and the Arctic Archipelago. In oceans, the dominant dispersal mechanism for prokaryotes and viruses is the movement of water masses, thus, dispersal for both groups is passive and similar. Nevertheless, spatial distance explained 7–19% of the variation in viral community composition in the Arctic Archipelago, but was not a significant predictor of bacterial or archaeal community composition in either sampling area, suggesting a decoupling of the processes regulating community composition within these taxonomic groups. According to the metacommunity theory, patterns in bacterial and archaeal community composition suggest a role for species sorting, while patterns of virus community composition are consistent with species sorting in the Labrador Sea and suggest a potential role of mass effects in the Arctic Archipelago. Given that, a specific prokaryotic taxon may be infected by multiple viruses with high reproductive potential, our results suggest that viral community composition was subject to a high turnover relative to prokaryotic community composition in the Arctic Archipelago.     

Benthic meiofaunal density and community composition in the deep White Sea and their temporal variations

In spite of the fact that shallow-water meiobenthos of the White Sea is a relatively well studied, the information on meiobenthic fauna from the deepest part of this sea is still very scanty. This study represents the first major study of the meiobenthos from the deep White Sea. The composition of the meiobenthic community, density and vertical distribution was studied during four sampling occasions in the deepest part of the Kandalaksha Depression (White Sea) in July 1998, October 1998, May 1999 and November 1999. Samples were collected from a depth of 270?m with the aid of a multicorer. The total density of meiobenthos in 1998 was twice than in 1999 (on average, 2,356 and 1,464 ind./10?cm², respectively). The most abundant meiobenthic group was Foraminifera (59?%), followed by Nematoda (26?%) and Harpacticoida (7?%). These relative and absolute abundance values are comparable with the same depth interval in Arctic and temperate regions. The density of foraminiferans and nematodes was higher in the autumn and lower in the summer. This may be explained by the mass propagation of these animals in the autumn season: the density of juvenile nematodes and small-sized foraminiferans increased significantly in the 1- to 4-cm-deep sediment layers in autumn. The size range of the meiobenthos in the deepest part of the White Sea was also comparable to deep-sea meiobenthos (the 63–125 and 125–250?μm size classes were most dominant).     

BENTHIC DIATOM AUTECOLOGY AND INFERENCE MODEL DEVELOPMENT FROM THE CANADIAN HIGH ARCTIC ARCHIPELAGO1

Diatom assemblages were analyzed from 64 lakes and ponds from Alert, Ellesmere Island and Mould Bay, Prince Patrick Island in the Canadian High Arctic Archipelago. Diverse water chemistry conditions and diatom communities were present in these sites. Small benthic taxa typically dominated diatom communities; however, assemblages were markedly different between Alert and Mould Bay sites in response to disparate water chemistry characteristics in the two regions. The most abundant taxa belonged to the genera Navicula, Cymbella, Achnanthes, Nitzschia, and Pinnularia. Canonical correspondence analysis indicated that pH, specific conductivity, dissolved organic carbon, and total phosphorus were the most important limnological variables in determining species composition. Diatom inference models were developed for pH, specific conductivity, and dissolved organic carbon using weighted averaging and weighted averaging partial least squares techniques; these had root mean square error of prediction/r²_boot values of 0.40/0.77, 0.28/0.70, and 0.24/0.55, respectively. These models are applicable to sites with large ranges of taxonomic and limnological variation and will allow the reconstruction of past changes of climate‐related limnological parameters from biostratigraphic records in future paleolimnological studies.     

Mycobiota of the giant oyster <Emphasis Type="Italic">Crassostrea gigas</Emphasis> (Thunberg, 1787) (Bivalvia) from the Peter the Great Bay of the Sea of Japan

Mycological investigation of the Pacific (giant) oyster Crassostrea gigas (Thunberg, 1793) (Bivalvia) from the Peter the Great Bay of the Sea of Japan was carried out. The taxonomic composition of filamentous fungi associated with C. gigas was studied. The taxonomic composition of the fungi associated with the giant oyster included 22 species of filamentous fungi of which 17 species were identified. The latter belonged to six genera: Alternaria, Aspergillus, Botrytis, Fusarium, Penicillium, and Trichoderma. The distribution of filamentous fungi in the internal organs of the bivalve mollusk was studied.     

The Phospholipid Composition of Nuclear Subfractions from Germinating Wheat Embryos

The content of phospholipids in chromatin, nuclear matrix, and nuclear membrane from wheat (Triticum aestivum L.) embryos was studied. Subfractions of intact nuclei from dry embryos were shown to differ in the content and composition of particular phospholipids. Embryo germination resulted in the redistribution of phospholipid between nuclear subfractions. A functional role of structural changes in the nuclear membrane due to this phospholipid redistribution is discussed. It is supposed that these rearrangements change nuclear membrane permeability and its surface charge.     

Pelagic larvae of the bivalves of Ussuriysky Bay, Sea of Japan

Based on materials of plankton surveying carried out in May–October 2008, the species composition, distribution, and density of pelagic larvae of bivalves of the Ussuriysky Bay (Peter the Great Bay, Sea of Japan) were studied. Larvae of 66 taxa were revealed and identified. The Bivalvia larvae occurred in the plankton during the entire period of study. Two areas, the inner and open part of the bay, which vary in the composition, concentration, and terms of larva occurrence in the plankton were distinguished. The larvae of Mytilus coruscus, Mactra chinensis, Modiolus kurilensis, Ruditapes philippinarum, Mya uzenensis and Teredo navalis were the most numerous and widespread. It was shown that despite high taxonomic diversity, the density of Bivalvia larvae in the Ussuriysky Bay was an order of magnitude lower, even in terms of their maximum number, than in other studied areas of the Peter the Great Bay.     

Metagenomic analysis of microbial communities of the sediments of the Kara Sea shelf and the Yenisei Bay

Microbial diversity in the sediments of the Kara Sea shelf and the southern Yenisei Bay, differing in pore water mineralization, was studied using massive parallel pyrosequencing according to the 454 (Roche) technology. Members of the same phyla (Cyanobacteria, Verrucomicrobia, Actinobacteria, Proteobacteria, and Bacteroidetes) predominated in bacterial communities of the sediments, while their ratio and taxonomic composition varied within the phyla and depended on pore water mineralization. Increasing salinity gradient was found to coincide with increased share of the γ-Proteobacteria and decreased abundance of α- and β-Proteobacteria, as well as of the phyla Verrucomicrobia, Chloroflexi, Chlorobi, and Acidobacteria. Archaeal diversity was lower, with Thaumarchaeota predominant in the sediments with high and low mineralization, while Crenarchaeota predominated in moderately mineralized sediments. Microbial communities of the Kara Sea shelf and Yenisei Bay sediments were found to contain the organisms capable of utilization of a broad spectrum of carbon sources, including gaseous and petroleum hydrocarbons.     

The distribution,size, and age composition,and growth of Saxidomus purpurata (Sowerby, 1852) (Bivalvia: Veneridae) in Vostok Bay,the Sea of Japan

Patterns of the distribution, the size and age composition of local populations, as well as the growth of the large bivalve Saxidomus purpurata, which is intensely farmed and reared in a number of East Asian countries, were studied for the first time in Russian Far East waters. It was determined that in the Vostok Bay, which is a bay of the second order within the limits of the Peter the Great Bay, S. purpurata forms local populations with densities of up to 7.5 ± 2.7 ind./m² and a biomass up to 1070.0 ± 384.0 g/m² at a depth of 1–9 m on mixed bottom substrates of boulders, pebbles, gravel, coquina, and sand of varying degrees of silting. The size and age composition of clam populations varies depending on the local environment; the shell length of the largest specimen was 98.6 mm, the greatest age was 23 years. In the Vostok Bay, the bivalve grew more slowly than off the coast of Korea and China and reached a commercial size (a shell length of 50 mm) later, at an age of 5–7 years. The von Bertalanffy equation describing the growth of S. purpurata in the aggregate sample of individuals from the Vostok Bay, has the form: L _t = 100.1[1 ? e^{?0.1675(t ? 0.0504)}]. It is assumed that the boundary of the species range goes north from the Peter the Great Bay, Sea of Japan.     

Species composition and distribution of free-living marine nematodes in Vostok Bay, Sea of Japan

The qualitative and quantitative composition of free-living marine nematodes have been studied in Vostok Bay (Peter the Great Bay, Sea of Japan). It is found that the population density of nematodes in the bottom sediments of Vostok Bay shows an uneven distribution. The mean population density equaled 56800 ± 23400 specimens/m². A correlation has been revealed between the population density of nematodes and the substrate type. Altogether, 85 species of nematodes have been found; they were dominated by Sabatieria palmaris, Rhabdodemania orientalis, Araeolaimus parvibulbosus, Oncholaimium paraolium, Doryolaimopsis peculiaris, and Metachromadora itoi. Six taxocenoses of nematodes were distinguished, taking into account the species dominating in the population density and using cluster analysis of the obtained data. The dominating trophic assemblage of nematodes was “scrapers.” In general, the species composition of nematodes in Vostok Bay is characterized by the relatively great similarity with that in other areas of Peter the Great Bay (Sea of Japan).     

Factors determining the spatial structure of benthic communities of a shallow bay

The species composition and the spatial structure of benthos were studied along a transect running at a depth of 1–18 m on the soft bottom substrates of Zapadnaya Bight of Furugelm Island (Peter the Great Bay, Sea of Japan). This area has been proposed as a major site for long-term monitoring of the Far Eastern State Marine Reserve. Hydrobiological samples of different sizes (16 cm², 0.025, and 1 m²) were taken by a diving method at 5-m intervals from the shore. Benthic communities were distinguished using principal component analysis (PCA), Sørensen's similarity indices, and similarity dendrograms. The grain size composition of bottom sediment was determined. Three benthic communities at depths of 1–3, 4–8, and 14–18 m and two transitional zones were distinguished in Zapadnaya Bight. The benthic communities are characterized by a relative constancy of species composition within their boundaries, and by stable ratios of quantitative characteristics of other species from different ecological groups. The transitional zones, which are comparable in extension with the communities themselves, are characterized by changes in species composition and the presence of characteristic species; here, the substrate type changes and sediment grain sorting is decreased.     

Richness and Diversity of Bacterioplankton Species along an Estuarine Gradient in Moreton Bay, Australia

Bacterioplankton community diversity was investigated in the subtropical Brisbane River-Moreton Bay estuary, Australia (27°25′S, 153°5′E). Bacterial communities were studied using automated rRNA intergenic spacer analysis (ARISA), which amplifies 16S-23S ribosomal DNA internally transcribed spacer regions from mixed-community DNA and detects the separated products on a fragment analyzer. Samples were collected from eight sites throughout the estuary and east to the East Australian Current (Coral Sea). Bacterioplankton communities had the highest operational taxonomic unit (OTU) richness, as measured by ARISA at eastern bay stations (S [total richness] = 84 to 85 OTU) and the lowest richness in the Coral Sea (S = 39 to 59 OTU). Richness correlated positively with bacterial abundance; however, there were no strong correlations between diversity and salinity, NO₃⁻ and PO₄³⁻ concentrations, or chlorophyll a concentration. Bacterioplankton communities at the riverine stations were different from communities in the bay or Coral Sea. The main differences in OTU richness between stations were in taxa that each represented 0.1% (the detection limit) to 0.5% of the total amplified DNA, i.e., the “tail” of the distribution. We found that some bacterioplankton taxa are specific to distinct environments while others have a ubiquitous distribution from river to sea. Bacterioplankton richness and diversity patterns in the estuary are potentially a consequence of greater niche availability, mixing of local and adjacent environment communities, or intermediate disturbance. Furthermore, these results contrast with previous reports of spatially homogeneous bacterioplankton communities in other coastal waters.     

Tyrosination-detyrosination of tubulin and microtubules during the development of chick erythrocytes

The protein composition of nuclear matrices containing different amount of DNA was examined. It was found that, in matrices containing 2% to 80% of total DNA, the quantity of DNA-bound proteins remains relatively constant varying from 10% to 15% of total nuclear proteins. Electrophoretic patterns do not differ substantially, but autoradiograms with in vitro ¹²⁵I labelled proteins show quantitative variations in the actin content. Application of radioimmunoassay (RIA) enabled to determine the exact content of actin in GAT nuclei and nuclear matrices – 5 g/ml in nuclei, of which 50% are bound to DNA and 3001o being a component of the protein part of the nuclear matrix. These results are supported by electron microscopic data, where immunogold technique was performed on thin sections and spread material. The applied methods suggest that part of the nuclear actin is tightly bound (resistant to 2 M NaCI) to DNA and represents a component of the internal nuclear matrix.     

The species composition and quantitative distribution of the diatom genus Pseudo-nitzschia H. Peragallo, 1990 in Russian waters of the Sea of Japan and the Sea of Okhotsk

This paper studies the species composition and quantitative distribution of diatoms that belong to the genus Pseudo-nitzschia in the Russian waters of the Sea of Japan and the Sea of Okhotsk. In total, 11 species of this genus were found in the area, including 7 that are known as being potentially toxic. The highest concentrations of Pseudo-nitzschia microalgae (1.4 × 10⁶–2.7 × 10⁶ cells/L) were found in the summer and autumn in the Peter the Great Bay of the Sea of Japan and the lowest concentrations (2.5 × 10²–1 × 10⁴ cells/L) were found in the Sakhalinsky and Akademiya bays of the Sea of Okhotsk. The species diversity of potentially toxic diatoms was greatest (seven species) and the cell concentrations highest (over 6 × 10⁵ cells/L) in the Peter the Great Bay, Sea of Japan, and in the Aniva Bay, Sea of Okhotsk. The density of potentially toxic species was highest near the northeastern coast of Sakhalin Island, in the Amur River estuary, and in adjacent waters. This paper also presents geographical distribution maps of Pseudo-nitzschia species and maps of the density distribution of potentially toxic microalgae over the studied area and identifies potential amnesic shellfish poisoning areas.     

Foraging conditions of planktotrophic larvae of echinoderms in the southwestern part of Peter the Great Bay of the Sea of Japan

Foraging of planktotrophic larvae of echinoderm common species in the Peter the Great Bay (Sea of Japan) was estimated on the basis of distribution of phyto- and meroplankton. The diversity and abundance of phytoplankton in the studied area in summer months were shown (141 algae species; abundance—up to 743000 cells/m³; biomass—more than 2.7 g/m³ of fresh weight). It was found that in Peter the Great Bay the diet of echinoderm larvae depended on their feeding behavior, duration of their pelagic stage, and abundance and size composition of phytoplankton, included up to several micrograms of fresh algae per larva.     

Diversity and guild structure of insect assemblages under grazing and exclusion regimes in a montane grassland from Central Argentina

The effects of grazing disturbance on insect communities were examined at a montane grassland in Central Argentina, by comparing two grazed sites differing in cattle load (heavy and continuous or moderate and discontinuous) and two cattle exclusions differing in age (7 and 19 years). Two aspects of insect diversity (taxonomic and guild structure) and two levels of taxonomic resolution (family and species) were considered. Four monthly samples were taken with a suction sampler in two 1 m² areas at each site. Collected specimens were counted, identified to family (all insects) or species (Coleoptera) level, and allocated to trophic guilds. Abundance, richness, diversity and biomass of the insect assemblages had minimum values in the most intensely grazed habitat, which also differed from the other sites in terms of insect families and Coleoptera species composition. It also showed a distinct guild structure, with fewer secondary consumers, and chewers replacing suckers as the most abundant herbivore group. According to these observations, intense grazing in montane grasslands in Central Argentina could result in taxonomic and guild changes in the associated insect communities, but such effects would not be noticeable with less intensive use. Moreover, using family taxonomic level could be as or even more appropriate than species level in order to characterize insect communities in the studied habitats under varying disturbance regimes.     

Spatially differing bacterial communities in water columns of the northern Baltic Sea

The Baltic Sea is a large, shallow, and strongly stratified brackish water basin. It suffers from eutrophication, toxic cyanobacterial blooms, and oxygen depletion, all of which pose a threat to local marine communities. In this study, the diversity and community structure of the northern Baltic Sea bacterial communities in the water column were, for the first time, thoroughly studied by 454 sequencing. The spring and autumn bacterial communities were one order of magnitude less diverse than those in recently studied oceanic habitats. Patchiness and strong stratification were clearly detectable; <1% of operational taxonomic units were shared among 11 samples. The community composition was more uniform horizontally (at a fixed depth) between different sites than vertically within one sampling site, implying that the community structure was affected by prevailing physical and hydrochemical conditions. Taxonomic affiliations revealed a total of 23 bacterial classes and 169 genera, while 5% of the sequences remained unclassified. The cyanobacteria accounted for <2% of the sequences, and potentially toxic cyanobacterial genera were essentially absent during the sampling seasons.     

Filamentous fungi in the epibiosis of the scallop Mizuhopecten yessoensis (Bivalvia) in Peter the Great Bay, Sea of Japan

This study considers the taxonomic composition of filamentous fungi in the epibiosis on the shell of the Yesso scallop Mizuhopecten yessoensis (Jay, 1856) (Bivalvia), which were collected in open waters of Peter the Great Bay, Sea of Japan. The taxonomic composition was found to include ten species of filamentous fungi, nine of which were identified. The revealed species belong to six genera, viz., Aspergillus, Aphanocladium, Cladosporium, Penicillium, Phialophorophoma, and Eurotium.     

Yermak Plateau revisited: spatial and temporal patterns of meiofaunal assemblages under permanent ice-coverage

Benthic sampling between 1997 and 2006 on the Yermak Plateau, a permanently ice-covered submarine peninsula northwest of Svalbard, exhibited regional differences with generally higher meiofauna numbers in southern and western parts (~2,250–2,300 ind. 10 cm⁻² in the south-west, compared with ~1,200–1,350 ind. 10 cm⁻² in the north-east). Distribution patterns suggest a current-driven lateral input of POM, produced in the high-productive Marginal Ice Zone, with increased intensity along the western slope of the plateau. Significant correlations between comparably ‘fresh’ sediment-bound phytodetritus and the taxonomic composition of meiofauna assemblages indicate that food quality decisively affects the community structure. The long-term development of meiobenthic communities showed no clear trend; however, a comparison of summer and winter data exhibited higher meiofauna densities and a more diverse composition in July samples. The predominance of small nematodes in the summer samples might point to reproductive activities stimulated by increased food availability. The taxonomic composition of nematode assemblages showed distinct regional differences, thereby indicating more stable environmental conditions in north-eastern parts of the Yermak Plateau.     

Spatial variability in structural and functional aspects of macrofauna communities and their environmental parameters in the Jade Bay (Wadden Sea Lower Saxony, southern North Sea)

Spatial distribution and functional structure of intertidal benthic macrofauna in relation to environmental variables in the Jade Bay (southern North Sea) were studied and compared with other intertidal areas of the Wadden Sea. A total of 128 stations covering the whole Jade Bay were sampled in summer 2009. A total of 114 taxa were found. Highest species numbers occurred in the subtidal areas, whereas highest mean abundances were found in the upper intertidal areas. Based on species abundance data, six significantly distinct macrofauna communities in the Jade Bay were identified and evaluated with multivariate statistics, univariate correlations and canonical correspondence analysis. Differences in these community patterns were caused by the response of the dominant species (Hydrobia ulvae, Tubificoides benedii, Pygospio elegans, Caulleriella killariensis, Scoloplos armiger, Urothoe poseidonis, Microprotopus maculatus) to prevailing environmental conditions along the gradient from the lower and exposed sandy intertidal areas via intermediate mixed sediments to the upper mudflat areas. Distribution patterns in relation to tidal zonation were best explained by variability in submergence time, Chlorophyll a (chl a) content and sediment composition (mud content), which are proxies for hydrodynamic conditions and food availability. Species inventory and species richness were comparable with other intertidal areas of the Wadden Sea, but the Jade Bay differs from these areas regarding dominant species. Differences in sediment composition and morphological characteristics (macrotidal versus mesotidal Wadden Sea areas) are discussed for comparison of regional differences.     

Nuclear cholesterol content and nucleoside triphosphatase activity are altered in the JCR:LA-cp corpulent rat

A nuclear pore complex-associated nucleoside triphosphatase (NTPase) activity is believed to provide energy for nuclear export of poly(A)+ mRNA. This study was initiated to determine if nuclear membrane lipid composition is altered during chronic hyperlipidemia, and what effect this has on NTPase activity. The JCR:LA-cp corpulent rat model is characterized by severe hypertriglyceridemia and moderate hypercholesterolemia, and thus represents an ideal animal model in which to study nuclear cholesterol and NTPase activity. NTPase activity was markedly increased in purified hepatic nuclei from corpulent female JCR:LA-cp rats in comparison to lean control rats as a function of assay time, [GTP], [ATP], and [Mg²⁺]. Nuclear membrane cholesterol and phospholipid content were significantly elevated in the corpulent animals. Nuclei of corpulent animals were less resistant to salt-induced lysis than nuclei of lean animals, suggesting a change in relative membrane integrity. Together, these results indicate that altered lipid metabolism in a genetic corpulent animal model can lead to changes in nuclear membrane lipid composition, which in turn may alter nuclear membrane NTPase activity and integrity. © 1996 Wiley-Liss, Inc.