Summer Ichthyoplankon in Onega Bay of the White Sea: Species Composition and Spatial Distribution

Data on the species composition and distribution of ichthyoplankton in Onega Bay of the White Sea are presented for June–July 2007, 2010–2012, and 2015–2016. In the ichthyoplankton, the specimens of the early developmental stages of 21 fish species were registered; the larvae of the White Sea herring Clupea pallasi marisalbi, capelin Mallotus villosus, and Pacific sand lance Ammodytes hexapterus were the most abundant. It is shown that the northwestern and southeastern zones, distinguished in Onega Bay by hydrophysical parameters, also differ in species composition and in ichthyoplankton abundance.     

Long-term environmental impact of an oil spill in the southern part of Onega Bay,the White Sea

Complex studies were carried out in the southern part of Onega Bay (White Sea) in the summer seasons of 2003–2006 and 2011–2013. These studies revealed the dynamics of oil pollution of the water area after an accidental fuel oil spill in September 2003 and its long-term adverse effects on organisms of different trophic levels of the coastal ecosystem (benthos, fish, and sea mammal populations) in the most polluted southeastern part of the bay. The deterioration of the status of the top trophic-level white whale population (a decrease in numbers) and the accumulation of oil hydrocarbons in tissues of benthic organisms are described.     

Peculiarities of summer phytoplankton spatial distribution in Onega Bay of the White Sea under local hydrophysical conditions

The species composition and phytoplankton biomass, concentrations of chlorophyll “a” (Chl) and nutrients in the surface water layer, and accompanying hydrophysical conditions were studied in Onega Bay of the White Sea in June 2015. The temperature and salinity of surface water layer and the water column stability varied greatly in the bay. The nutrients' concentrations exceeded the limiting threshold necessary for the phytoplankton development. The phytoplankton abundance was relatively low, averaged as 13.46 ± 9.00 mg C/m³ (total phytoplankton biomass), 0.78 ± 0.43 mg/m³ (concentration of chlorophyll “a”), and 0.18 ± 0.27 mg C/m³ (picophytoplankton biomass). The highest phytoplankton biomass has been registered along the frontal zones. Three phytoplankton communities that differed significantly in their structure have been found.     

Characteristics of the energy metabolism of the White Sea herring <Emphasis Type="Italic">Clupea pallasii marisalbi</Emphasis> Berg (Clupeiformes,Clupeidae) of Onega Bay,Dvina Bay,and Kandalaksha Bay of the White Sea

The activity of the enzymes of the energy and carbohydrate metabolisms (cytochrome-c oxidase, L-lactate dehydrogenase, aldolase, and glycerol-1-phosphate dehydrogenase) have been studied in White Sea herring (the 1+, 2+, and 3+ age groups) sampled in Onega Bay, Dvina Bay, and Kandalaksha Bay of the White Sea. The bays differ in the hydrological regime, ecological and feeding conditions. The individual variability of the enzyme activity was the largest in the herring of the age 1+. The flexibility of the intensity and vector of the basic metabolic reactions probably supports the energy homeostasis, preconditions the switching to the most effective way of using the resources, and regulates the synthesis of the structural and storage molecules, as well as vectors the adaptation strategy of herring specimens of each age group to the hydrological regime, environment, and feeding conditions of the particular bay, corresponding to their age-related characteristics.     

Seasonal Variations in the Structure of an Anoxygenic Phototrophic Bacterial Community from the Meromictic Lake Trekhtsvetnoe (Kandalaksha Bay,White Sea)

Microbiology - The community of anoxygenic phototrophic bacteria (APB) from the water column of the meromictic Lake Trekhtsvetnoe (Kandalaksha Bay, White Sea, Russia) was studied in March 2012 and...     

The species composition and distribution of ostracods (Crustacea,Ostracoda) in rockpools on islands in the Kandalaksha Bay of the White Sea

A total of 15 species of ostracods of 7 genera and 3 families of the suborder Podocopa Sars have been recorded in rockpools of the Kandalaksha Bay in the White Sea. Among them, Potamocypris pallida Alm is a new species for the fauna of Russia. Data on species composition and the dominant complex and ecological features of ostracods which inhabit waters of rockpools are presented.     

The dynamics of the abundance, age, and sex structure of the Solovetsky reproductive gathering of the Beluga whale Delphinapterus leucas (Onega Bay, White Sea)

Based on the data from long-term research in 1999?C2009 we studied the population dynamics of Beluga whales in the Solovetsky reproductive gathering (RG) in the White Sea. This aggregation of Beluga whales is formed each year in the second half of May after the break-up of fast ice and persists to September inclusive. The aggregation numbers about 100 individuals from visual observations, with long-term variations of 20?C30 individuals. The percentage of whales of different age groups also varied in the gathering depending on year, but typically one half was formed by mature animals and the other half consisted of immature whales and yearlings. There are two pronounced peaks in numbers for the summer season in the Solovetsky Beluga RG. The number of Belugas increased with the appearance of males and females that were ready to breed and females that were ready to bear calves. The daily dynamics of Belugas in the gathering largely depended on the time of day and tidal regime. In the summer season, the state of the sea and human impacts were key factors in number fluctuations of the Belugas of the Solovetsky RG. The revealed negative correlation of the long-term population of Belugas in the gathering on air temperature is considered as a special instance of general laws of the migration activities of Beluga whales in the White Sea.     

Abundance and pigment type composition of picocyanobacteria in Barguzin Bay, Lake Baikal

In Lake Baikal, picocyanobacteria are the most important primary producers during the summer. Freshwater picocyanobacteria are discriminated into either the phycoerythrin (PE)-rich or the phycocyanin (PC)-rich types according to their pigment composition. The distributions of these two types of picocyanobacteria were investigated in Barguzin Bay. The PC-rich type accounted for >98% of the total picocyanobacteria at the station near the shore of the bay where river water flows directly in. In the offshore area of the lake, all of the picocyanobacteria cells were of the PE-rich type. In addition, the occurrence of the PC-rich type was restricted to the station, where the attenuation coefficient exceeded 0.25 m⁻¹. Near the shore, where the turbidity was high (>1 NTU), the cell densities of both the PE- and PC-rich types increased away from the river mouth. This indicates that the PC-rich type cells grow near the shore of the bay where turbidity is high. Since the PC-rich type could not grow well when cells were incubated in offshore lake water, restricted distribution of the PC-rich type could also be explained by their growth capability. The present study clearly demonstrated the shift in the pigment type composition of picocyanobacteria from the coastal to the pelagic zone of Lake Baikal. The co-existence of the two pigment types probably enables the abundance of the picocyanobacterial community to be stable over a broader range of environmental conditions than would be possible for a single pigment type.     

Species composition and distribution of summer ichthyoplankton in Chupa Estuary (Kandalaksha Bay of the White Sea)

On the basis of ichthyoplankton surveys performed in July 2002 and June 2004–2005 in Chupa Estuary and adjacent waters of Kandalaksha Bay, species composition and distribution of eggs and larvae of fish were studied. Early stages of development of seven fish species were found in the composition of ichthyoplankton. The bulk of abundance of ichthyoplankton was formed of Clupea pallasii marisalbi larvae. It was shown that the sites of aggregation of larval C. pallasii marisalbi from June to July are constant and located in the central and preestuarine areas of Chupa Estuary. Possible routes of their passive migrations within Chupa Estuary and the adjacent water area of Kandalaksha Bay are considered. It is suggested that the drift of larvae beyond the estuary proceeds slowly, and after hatching they can long stay in the estuary concentrating in its central and preestuarine areas.     

Spatial and Temporal Variability in the Abundance and Size Structure of Larvae of the White Sea Herring (<Emphasis Type="Italic">Clupea pallasii marisalbi</Emphasis>) in Onega and Kandalaksha Bays of the White Sea

According to the data of ichthyological surveys conducted in Onega and Kandalaksha bays of the White Sea in June 2015, the abundance and pattern of spatial distribution of larvae of the White Sea herring Clupea pallasii marisalbi are comparable with those of 2012. Aggregations of herring larvae detected at a distance of 12?14 km from the coast in the apex part of Kandalaksha Bay are probably the result of their mass drift caused by fresh floodwater discharge. In coastal waters of the bays adjacent to the littoral part, the abundance of herring larvae above the depths less than 5 m varies considerably due to their drift under effect of alongshore and/or tidal currents. The White Sea herring larvae reach high abundance only in the inlets (Chupa, Knyazhaya, Belaya, and Maikova inlets) with the river runoff; their length increases with the distance from spawning grounds. In different years, the main bulk of herring larvae in Knyazhaya Inlet is concentrated at depths about 12–15 m at 6?8°C, or moved to the upper 5-m quasi-homogeneous layer when the water temperature at the depth was 0?1°C.     

Behavioral and acoustical characteristics of the reproductive gathering of beluga whales (Delphinapterus leucas) in the vicinity of Myagostrov, Golyi Sosnovets, and Roganka Islands (Onega Bay, the White Sea)

The structure of the summer reproductive gathering of beluga whales Delphinapterus leucas was studied in the vicinity of Myagostrov, Golyi Sosnovets, and Roganka islands (Onega Bay, the White Sea) in 2006 and 2008. The abundance, age and sex structure, behavior, and swimming and acoustic behavior were studied in detail.     

Seasonal variation in the species composition of tintinnid cilates in Hiroshima Bay, the Seto Inland Sea of Japan

Seasonal changes in the species composition of tintinnid ciliateswere examined based on time-series samples taken at 2 week intervalsover a 3 year period in Hiroshima Bay, the Seto Inland Sea ofJapan. The maximum abundance of total tintinnids over the entireperiod was 5.7 x 10³ indi viduals l^– Among 32 speciesidentified, a consistent seasonal occurrence was recognizedin 22 species. The relationships between various environmentalfactors and the abundance of each species of tintinnids wereanalyzed using principal component analysis From this analysis,the abundance of many tintinnids was revealed to be associatedwith temperature, the <20 µm size fraction of chlorophylla and water column stability, but not with the <20 µmsize fraction of chlorophyll a, nor with salinity. From theseresults, tintinnid species were divided into five associationtypes: species whose abundance increased with increasing temperature,decreasing temperature, nanophytoplankton abundance, increasingwater column mixing, or increasing water stratification coupledwith low temperature.     

The species composition and pattern of distribution of hermit crabs (Decapoda: Paguroidea) in Vostok Bay,Sea of Japan

The species composition, abundance, and vertical distribution of hermit crabs (Decapoda: Paguroidea) were investigated in Vostok Bay, Sea of Japan, from September 2014 to September 2015. A total of seven species from two families were found in the monitoring area of approximately 5000 m² located on the bottom within a depth range of 0–11 m: Pagurus minutus, P. proximus, P. brachiomastus, P. pectinatus, P. ochotensis, P. middendorffii (Paguridae), and Areopaguristes hirsutimanus (Diogenidae). Their population density varied from 22 ± 13 to 26 ± 2 ind./m²; the biomass varied from 55.76 ± 26.10 to 93.38 ± 27.00 g/m². The species composition remained invariable throughout the study period. The proportions of species abundance changed between seasons, as this parameter is largely determined by seasonal migrations of hermit crabs. Pagurus minutus predominated in number in winter and spring (up to 71%); P. proximus, in summer and autumn (up to 47%). In autumn and spring, P. ochotensis and P. pectinatus constituted a major part of biomass (18–25% and 19–20%, respectively). The proportion of a previously abundant species, P. middendorffii, was very small (no larger than 1.3%) during the study period. Another four species of hermit crabs occurred in other parts of Vostok Bay; thus, the fauna of the bay currently includes 11 species of this group.     

Microbial Community of a Marine Meromictic Trough (Biofilter Bay) in the Kandalaksha Bay,White Sea

Microbiology - The composition of microbial communities and the rates of microbial processes in the water column of a meromictic trough in the Biofilter Bay, Kandalaksha Bay, White Sea were...     

Peculiarities of the Structure of and Trends in the Macrobenthos Community of the Ermolinskaya Bay Lagoon Ecosystem,Kandalaksha Bay,White Sea

The species composition and spatial and trophic structures of the macrobenthos communities of the Ermolinskaya Bay were studied, and the main changes that had occurred since previous explorations (the 1960s) were analyzed. The most significant changes in the spatial structure of the macrobenthos community (species diversity, population density and biomass, and similarities of the species’ distribution) were observed with regard to the sea level zone: the most pronounced at the upper littoral, followed by the middle littoral, lower littoral, and sublittoral. The longitudinal gradient of the community structure (from the innermost area seaward) was pronounced less strongly. Altogether, four macrobenthos communities can be identified in Ermolinskaya Bay; they differ in species composition, diversity, population density and biomass, and trophic structure: (1) community of the upper littoral with the dominance of collecting deposit feeders, Hydrobia ulvae, and scrapers, Littorina saxatilis; (2) community of the middle littoral with the prevalence of deposit feeders, Hydrobia ulvae and Macoma balthica, seston feeders, Mya arenaria, and, to a lesser extent, Mytilus edulis; (3) community of the lower littoral with the domination of the filtering organisms, Mytilus edulis, to a lesser extent collecting deposit feeders, Hydrobia ulvae and Macoma balthica, and scrapers, Littorina littorea; and (4) community of the sublittoral, where the leading positions belong to the group of collecting deposit feeders, Macoma balthica, to a lesser extent also Hydrobia ulvae (in the innermost area) and Capitella capitata, Arenicola marina (in the marine part of the bay). The gradual siltation of the bay and the reduction of its connection to the sea have led to the development of a littoral complex of species in the sublittoral, whereas the species typical at the sublittoral in the 1960s are now mainly found at the outlet of the bay.     

Abundance of Naked Amoebae in Sediments of Hiroshima Bay, Seto Inland Sea of Japan

ABSTRACT The present paper provides the first data on naked amoebae from sediments of Hiroshima Bay. Three stations in the inner part of the bay were sampled over a three-month period. Abundance of naked amoebae ranged from 1,019 to 45,561 cells/g dry sediment. Results indicate: (i) surface sediment populations in most cases were higher than subsurface populations; (ii) there was some evidence of temporal variation with counts generally increasing from March to May: and (iii) the site located near Hiroshima City had fewer amoebae on several occasions than the other two sites. There was a negative exponential relationship between acid-volatile sulfide concentration and abundance of amoebae. Most amoebae were small with the average size ranging from 6.6–14 μm. Morphotype 1, amoebae that extend lobose pseudopodia or subpseudopodia during normal locomotion, were dominant (40–100% of enumerated amoebae). Morphotypes 2 and 3 (limax amoebae) were found in lower numbers than the other two morphotypes. The proportion of amoebae occupied by Morphotype 4 (fan-shaped or discoidal-flattened amoebae) was higher at a lower total abundance.     

Anoxygenic phototrophic bacteria of the Kislo-Sladkoe stratified lake (White Sea,Kandalaksha Bay)

The community of anoxygenic phototrophic bacteria (APB) in the water column of the Kislo-Sladkoe stratified lake recently isolated from the sea (White Sea, Kandalaksha Bay) was investigated in September 2010. The water of the sulfide-rich zone was greenish-brown due to intense development of green sulfur bacteria (GSB). Nine APB strains were isolated from the water samples: three belonging to GSB, five, to purple sulfur bacteria (PSB), and one, to purple nonsulfur bacteria (PNB). GSB predominated in the phototrophic community of the chemocline. Unexpectedly, two morphologically different green-colored GSB strains were found to be phylogenetically identical and related to the brown-colored Chlorobium phaeovibrioides (99% similarity according to the 16S rRNA gene sequencing). Homology to the closest green-colored species (Chlorobium luteolum) was 98%. Two morphologically and physiologically similar PSB strains (TcrPS10 and AmPS10) had rounded cells containing okenone and gas vesicles. According to the 16S rRNA gene sequencing, these strains were most closely related (99%) to two different Thiocapsa species: Tca. marina (containing okenonee and no gas vesicles) and Tca. rosea (containing spirilloxanthin and gas vesicles). The remaining isolates of purple bacteria were similar to the already described APB species.     

Abundance, species composition of microzooplankton from the coastal waters of Port Blair, South Andaman Island

ABSTRACT: BACKGROUND: Microzooplankton consisting of protists and metazoa <200 mum. It displays unique feeding mechanisms and behaviours that allow them to graze cells up to five times their own volume. They can grow at rates which equal or exceed prey growth and can serve as a viable food source for metazoans. Moreover, they are individually inconspicuous, their recognition as significant consumers of oceanic primary production. The microzooplankton can be the dominant consumers of phytoplankton production in both oligo- and eutrophic regions of the ocean and are capable of consuming >100% of primary production. RESULTS: The microzooplankton of the South Andaman Sea were investigated during September 2011 to January 2012. A total of 44 species belong to 19 genera were recorded in this study. Tintinnids made larger contribution to the total abundance (34%) followed in order by dinoflagellates (24%), ciliates (20%) and copepod nauplii (18%). Foraminifera were numerically less (4%). Tintinnids were represented by 20 species belong to 13 genera, Heterotrophic dinoflagellates were represented by 17 species belong to 3 genera and Ciliates comprised 5 species belong to 3 genera. Eutintinus tineus, Tintinnopsis cylindrical, T. incertum, Protoperidinium divergens, Lomaniella oviformes, Strombidium minimum were the most prevalent microzooplankton. Standing stock of tintinnids ranged from 30--80 cells.L-1 and showed a reverse distribution with the distribution of chlorophyll a relatively higher species diversity and equitability was found in polluted harbour areas. CONCLUSIONS: The change of environmental variability affects the species composition and abundance of microzooplankton varied spatially and temporarily. The observations clearly demonstrated that the harbor area differed considerably from other area in terms of species present and phytoplankton biomass. Further, the phytoplankton abundance is showed to be strongly influenced by tintinnid with respect to the relationship of prey--predator. Consequently, further investigation on microzooplankton grazing would shed light on food web dynamics.     

Phototrophic Picoplankton in Temperate Lakes: Seasonal Abundance and Importance along a Trophic Gradient

The seasonal development of autotrophic picoplankton was investigated in seven Danish lakes representing a eutrophication gradient. Highest cell abundance between 1.5 to 6 × 10⁵ cells ml⁻¹ were found in mid-summer. Minor peaks were observed in spring. In winter, densities were below 10³ ml⁻¹. The highest relative picoplankton contribution to total autotrophic biomass also occurred in mid-summer. In the eutrophic lakes and one humic lake the average seasonal contribution of picoplankton to total chlorophyll was below 1% increasing to 5-8% in the meso- and oligotrophic clear water lakes. During short periods the proportion of picoplankton did reach 25%. The higher relative importance of picoplankton in less productive lakes was not due to higher actual chlorophyll concentrations, but due to a much more pronounced response by larger algae at higher nutrient loading. Both cyanobacteria and eukaryote organisms were present as picoplankton. Only eukaryotes were found in one eutrophic lake and an acidic, humic lake. In the eutrophic lakes eukaryote picoplankton was dominant; both with respect to cell densities and biovolume, whereas cyanobacteria dominated the two meso-oligotrophic lakes. Autotrophic picoplankton were present in all lake types, however their importance seemed to be less in most eutrophic lakes than in less productive, meso-oligotrophic lakes.