Species diversity of heterotrophic flagellates in White Sea littoral sites

The species diversity and distribution of benthic heterotrophic flagellates in sediment samples from along the salinity gradient in the Chernaya River Estuary and from Velikaya Salma Strait (Kandalaksha Bay, the White Sea) were investigated during August 2004. One hundred and six taxa have been identified by means of phase and interference contrast light microscopy and transmission electron microscopy. The majority of observed flagellates were bacterivores. The species diversity of the following groups: choanoflagellates, euglenids, kinetoplastids, bicosoecids, chrysomonads, thaumatomonads and flagellates Incertae sedis was the highest. Ancyromonas sigmoides and Petalomonas pusilla were the most common species. The species richness was lowest in the brackish water estuarine part with salinity levels between 5 per thousand and 8 per thousand. The distribution of heterotrophic flagellates conforms to the so-called "rule of critical salinity", possessing, apparently, the same universal character for organisms of different size levels. Heterotrophic flagellate communities in these littoral sites were highly heterogeneous. The curve of "cumulative species number vs. sampling effort" is well fitted by equation S=21.17N(0.50) and unsaturated, which indicates that more intensive investigations of the heterotrophic flagellates in the White Sea should be expected to reveal more species.     

Carbonate system of the Razdolnaya River estuary (Amur Bay, Sea of Japan)

Two methods, the total alkalinity measurement by Bruevich [4] and pH measurement in a cell without liquid junction [11], were suggested for study of the carbonate system of estuaries. Based on new measurements, the empirical equations were obtained for the first and second seawater concentration constants of carbonic acid for the ranges of salinity 0–40 and temperatures 0–30°C. Applying the constants and above methods, we studied the carbonate system of the Razdolnaya River-Amur Bay estuary in two expeditions of July 2001, the first in a period of average water level and the second after a flood. In the latter survey, extremely low values (60 µatm) of pCO₂ (carbon dioxide partial pressure) were recorded in the seaward part of the estuary and extremely high ( 13 300 µatm) were noted in the river. High pCO₂ in the surface water was caused by intense bacterial activity, and low levels were caused by phytoplankton bloom. The nonconservative behavior of the total alkalinity and dissolved inorganic carbon was revealed in the estuary. Based on the data of the carbonate system, the production/destruction of organic matter was assessed.Original Russian Text Copyright © 2005 by Biologiya Morya, Tishchenko, Wong, Volkova, Gramm-Osipov, Johnson, Dudarev, Zvalinskii, Nedashkovskii, Pavlova, Chichkin, Sagalaev, Shevtsova, Shkirnikova.     

The Biogeochemical Cycle of Methane in the Coastal Zone and Littoral of the Kandalaksha Bay of the White Sea

Microbiological and biogeochemical investigations of the processes of methane production (MP) and methane oxidation (MO) in the coastal waters and littoral of the Kandalaksha Bay of the White Sea were carried out. The studies were conducted in the coastal zones and in the water areas of the Kandalaksha Preserve, Moscow State University White Sea Biological Station, and the Zoological Institute (RAS) biological station in August 1999, 2000, and 2001 and in March 2001. The rate of CO₂ assimilation in the shallow and littoral sediments was 35–27800 g C/(dm³ day) in summer and 32.8–88.9 g C/(dm³ day) in winter. The maximal rates of MP were observed in the littoral sediments in the zone of macrophyte decomposition, in local depressions, and in the estuary of a freshwater creek (up to 113 l/(dm³ day)). The maximal level of MO was observed in the shallow estuarine sediments (up to 2450 l/(dm³ day)). During the winter season, at the temperature of –0.5 to 0.5°C, the MP rate in the littoral sediments was 0.02–0.3 l/(dm³ day), while the MO rate was 0.06–0.7 l/(dm³ day). The isotopic data obtained indicate that the C_org of the mats and of the upper sediment layers is enriched with the heavy ¹³C isotope by 1–4 as compared to the C_org of the suspension. A striking difference was found between the levels of methane emission by the typical littoral microlandscapes. In fine sediments, the average emission was 675 l CH₄/(m² day); in stormy discharge stretch sediments, it was 1670 l CH₄/(m² day); and under stones and in silted pits, 1370 l CH₄/(m²day). The calculation, performed with consideration of the microlandscape areas with a high production, allowed the CH₄ production of 1 km² of the littoral to be estimated as 192–300 l CH₄/(km² day).     

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.     

Salinity tolerances of 62 strains of Pflesteria and Pfiesteria-like heterotrophic flagellates (Dinophyceae)

The salinity tolerance of 62 strains of Pfiesteria and Pfiesteria‐like heterotrophic dinoflagellates was measured. All strains were acclimated at 12 psu for at least 1 year before experimentation. Strains isolated from the Chesapeake Bay and Neuse River systems tolerated lower salinities than strains isolated from the Wilmington River system (P< 0.005). Swimming cells were still observed after 5 days at 0.5 psu for one strain, and at 1 psu for most other Chesapeake Bay and Neuse River strains. Swimming cells for the Wilmington River were still observed after 5 days at 3–5 psu, but no swimming cells were observed at ≤ 2 psu. With regard to the upper salinity tolerance, the Wilmington River strains tolerated higher salinities than the Chesapeake Bay and Neuse River systems (P< 0.005). Most Wilmington River strains were swimming after 5 days at salinities ≥ 50 psu, whereas the Chesapeake Bay and Neuse River system strains rarely had swimming cells at salinities exceeding 35–45 psu. For all three water systems and for both lower and higher salinities, cells apparently encysted in many instances. However, when salinities were returned to 12 psu, swimming cells often re‐appeared. Statistically significant geographic differences in salinity tolerance suggest a geographic adaptation has occurred and that salinity tolerance is under genetic control. The results also suggest there is diversity among the strains.     

The Process of Microbial Sulfate Reduction in Sediments of the Coastal Zone and Littoral of the Kandalaksha Bay of the White Sea

Microbiological and biogeochemical investigations of the coastal zone and the littoral of the Kandalaksha Bay of the White Sea were carried out. The material for investigations was obtained in the series of expeditions of the Institute of Microbiology, Russian Academy of Sciences, in August 1999, 2000, 2001, and in March 2003. The studies were conducted on the littoral and in the water area of the Kandalaksha Preserve, the Moscow University Belomorsk Biological Station, and the Zoological Institute Biological Station, Russian Academy of Sciences. Sediment sampling on the littoral was carried out in the typical microlandscapes differing in the sediment properties and macrobenthos distribution. The maximal sulfate reduction rate (SRR) was shown for the shallow part of the Chernorechenskaya Bay (up to 2550 g S/(dm³ day)) and in the Bab'ye More Bay (up to 3191 g S/(dm³ day)). During the winter season, at a temperature of –0.5 × 0.5°C, the SRR in the sediments of the Kartesh Bay was 7.9 × 13 g S/(dm³ day). In the widest limits, the SRR values varied in the sediment cores sampled on the littoral. The minimal values (11 g S/(dm³ day)) were obtained in the core samples on the silt–sandy littoral. The littoral finely dispersed sediments rich in organic matter were characterized by high SRR values (524–1413 g S/(dm³ day)). The maximal SRR values were shown for the sediments present within the stretch of decomposing macrophytes, in local pits at the lower littoral waterline, and in the mouth of a freshwater stream (51–159 mg S/(dm³ day)). A sharp difference in the level of H₂S production in the type microlandscapes was shown. The average hydrogen sulfide production in finely dispersed sediments constituted 125 mg S/(m² day); in stormy discharge deposits, 1950 mg S/(m² day); in depressions under stones and in silted pits, 4300 mg S/(m² day). A calculation made with regard to the area of microlandscapes with increased productivity shows that the daily H₂S production per 1 km² of the littoral (August) is 60.8 to 202 kg S/(km² day), while the organic carbon consumption for sulfate reduction per 1 km² of the littoral is 46 to 152 kg C_org/(km² day).     

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...     

The biogeochemical cycle of methane in the coastal zone and littoral of the Kandalaksha Bay of the White Sea

Microbiological and biogeochemical investigations of the processes of methane production (MP) and methane oxidation (MO) in the coastal waters and littoral of the Kandalaksha Bay of the White Sea were carried out. The studies were conducted in the coastal zones and in the water areas of the Kandalaksha Preserve, Moscow University White Sea Biological Station, and Zoological Institute (RAS) Biological Station in August, 1999, 2000, and 2001 and in March, 2001. The rate of CO2 assimilation in the shallow and littoral sediments was 35-27800 microg C/(dm3 day) in summer and 32.8-88.9 microg C/(dm3 day) in winter. The maximal rates of MP were observed in the littoral sediments in the zone of macrophyte decomposition, in local depressions, and in the estuary of a freshwater creak (up to 113 microl/(dm3 day)). The maximal level of MO was observed in the shallow estuarine sediments (up to 2450 microl/(dm3 day)). During the winter season, at the temperature of -0.5 to 0.5 degrees C, the MP rate in the littoral sediments was 0.02-0.3 microl/(dm3 day), while MO rate was 0.06-0.7 microl/(dm3 day). The isotopic data obtained indicate that the C(org) of the mats and of the upper sediment layers is enriched with the heavy 13C isotope by 1-4 per thousand as compared to the C(org) of the suspension, comprised on 33.5-34.3% of phytoplankton. A striking difference was found between the levels of methane emission by the typical littoral microlanscapes. In fine sediments, the average emission was 675 microl CH4/(m2 day), in the stormy discharge stretch sediments it was 1670 microl CH4/(m2 day), and under the stones and in silted pits, 1370 microl CH4/(m2 day). The calculation performed with consideration of the microlandscape areas with a high production allowed the CH4 production of 1 km2 of the littoral to be estimated as 192-300 1 CH4/(km2 day).     

The Influence of Salinity on Early Ontogeny of the Mussel Mytilus edulisand the Starfish Asterias rubensfrom the White Sea

The influence of increased and decreased salinity on early larvae of the mussel Mytilus edulisL. and the starfish Asterias rubensfrom the White Sea is studied. Fertilized egg cells, embryos, larvae, and yearlings of the two species were compared. Salinity tolerance changes with the stage of development of mussels and starfish. Morphological changes occurring in eggs and embryos exposed to extremely high and low salinities are reported.     

Succession processes in the anoxygenic phototrophic bacterial community in Lake Kislo-Sladkoe (Kandalaksha Bay,White Sea)

The community of anoxygenic phototrophic bacteria (APB) in the water column of Lake Kislo- Sladkoe (Kandalaksha Bay, White Sea), which has recently become separated from the sea, was investigated in March?April 2012, March?April 2013, and in September 2013. The lake, which was previously considered meromictic, was in fact mixed and was strongly affected by the sea. In winter the lake is sometimes washed off with seawater, and this together with the seasonal cycles of succession processes determines the succession of the community. The consequences of the mixing in autumn 2011 could be observed in the APB community as late as autumn 2013. Green-colored green sulfur bacteria (GSB) usually predominated in the chemocline. In winter 2013 stagnation resulted in turbidity of water under the ice, which was responsible for both predominance of the brown GSB forms and the changes ratio of the species of purple sulfur bacteria (PSB) in anoxic water layers. Production of anoxygenic photosynthesis in the lake was at least 240 mg C m^-2 day^-1 in September and 0–20 mg C m^–2 day^–1 in March—April, which corresponded to 40 and 69%, respectively, of oxygenic photosynthesis. Okenone-containing purple sulfur bacteria, strain TcakPS12, were isolated in 2012 from lake water. The ells of this strain form filaments of not separated cells. Strain TcakPS12 exhibited 98% similarity with the type strains of Thiocapsa pendens DSM 236 and Thiocapsa bogorovii BBS, as well as with the strains AmPS10 and TcyrPS10, which were isolated from Lake Kislo-Sladkoe in 2010.     

Microbiological and isotopic geochemical investigation of Lake Kislo-Sladkoe,a meromictic water body at the Kandalaksha Bay shore (White Sea)

Microbiological, biogeochemical, and isotopic geochemical investigation of Lake Kislo-Sladkoe (Polusolenoe in early publications) at the Kandalaksha Bay shore (White Sea) was carried out in September 2010. Lake Kislo-Sladkoe was formed in the mid-1900s out of a sea gulf due to a coastal heave. At the time of investigation, the surface layer was saturated with oxygen, while near-bottom water contained sulfide (up to 32 mg/L). Total number of microorganisms was high (12.3 × 10⁶ cells/mL on average). Light CO₂ fixation exhibited two pronounced peaks. In the oxic zone, the highest rates of photosynthesis were detected at 1.0 and 2.0 m. The second, more pronounced peak of light CO₂ fixation was associated with activity of anoxygenic phototrophic bacteria in the anoxic layer at the depth of 2.9 m (413 μg C L^?1 day^?1). Green-colored green sulfur bacteria (GSB) predominated in the upper anoxic layer (2.7–2.9 m), their numbers being as high as 1.12 × 10⁴ cells/mL, while brown-colored GSB predominated in the lower horizons. The rates of both sulfate reduction and methanogenesis peaked in the 2.9 m horizon (1690 μg S L^?1 day^?1 and 2.9 μL CH₄ L^?1 day^-1). The isotopic composition of dissolved methane from the near-bottom water layer (δ¹³C (CH₄) = ?87.76‰) was significantly lighter than in the upper horizons (δ¹³C (CH₄) = ?77.95‰). The most isotopically heavy methane (δ¹³C (CH₄) = ?72.61‰) was retrieved from the depth of 2.9 m. The rate of methane oxidation peaked in the same horizon. As a result of these reactions, organic matter (OM) carbon of the 2.9 m horizon became lighter (?36.36‰), while carbonate carbon became heavier (?7.56‰). Thus, our results demonstrated that Lake Kislo-Sladkoe is a stratified meromictic lake with active microbial cycles of carbon and sulfur. Suspended matter in the water column was mostly of autochthonous origin. Anoxygenic photo-synthesis coupled to utilization of reduced sulfur compounds contributed significantly to OM production.     

Production of planktonic crustaceans in the White Sea

This paper analyzes different methods for assessment of the production of marine organisms. The estimated values of annual production and ration of planktonic copepods of the White Sea are 5.0 × 10¹² and 2.2 × 10¹³ kcal, respectively. Comparison of the planktonic copepod ration with phytoplankton production shows that the energy demands of the copepod community are met by consumption of phytoplankton and, probably, also bacterioplankton and detritus.     

On the spatial distribution of larval White Sea herring (Clupea pallasii marisalbi) in estuaries of Kandalaksha Bay of the White Sea

According to results of layer-by-layer fishings performed in June 2006 in the Knyazhaya and Kolvitsa estuaries, data on the spatial distribution of larval White Sea herring Clupea pallasi marisalbi during the tidal cycle are provided. In these estuaries, the presence of a system of counter-currents that form a two-layer circulation was revealed. The surface current that is directed to the bay is traced to a depth of 2–4 m; below this, a current directed to the tail part of estuaries was recorded. It was established that larval herrings perform vertical migrations, as a result of which they can be freely drifted from inlets with a surface current and penetrate back from the adjoining water areas with a counter-current, which promotes a decrease in their drift in the open part of Kandalaksha Bay beyond shallow zones of juvenile feeding.     

Juvenile Atlantic salmon in the Varzuga River (White Sea Basin)

In the Varzuga River (Kola Peninsula), juvenile Atlantic salmon occur at a high mean density of 1·1 individuals per m², with a relatively low growth rate, reaching c. 8 g at age 3. They migrate to sea at ages 2–4 before they are fully silvered. Mortality is not high and the fish forage in the estuary where they grow fast and acclimate to the pelagic and high salinity habitat.     

Salinity Adaptations and Bathymetric Distribution of Bivalve Mollusks Portlandia arcticaand Nuculana pernula in the White Sea

We examined changes in the oxygen consumption rate, the number of active animals, rate of losses of salts, and the level of cell hydration under conditions of decreased salinity in the mollusks Portlandia arctica(Gray) and Nuculana pernula(O.F. Müller), inhabiting the White Sea in the deepest depths under high salinity (about 30) and negative temperatures of –1.3 to –1.4°C throughout the year. It has been shown that the mollusks demonstrate a relatively great tolerance of desalination at the organism level and a capability to regulate cell volume under decreased salinity of the environment. We concluded that the depletion of fauna of the White Sea in the deepest depths is not connected with the tolerance level of deep-sea animals to salinity fluctuations, but rather is due to environmental conditions (liquid silts and negative temperatures).     

Long-term dynamics of the abundance of several intertidal polychaetes in two inlets of Kandalaksha Bay (White Sea)

Based on eigenvector filtering and phase surface methods, the correlation between abundance dynamics and water temperature was studied in seven species of White Sea littoral polychaetes. Cyclic fluctuations in abundance with periods of approximately 5 and 12 years were revealed. Some instances of the 5-year cycles of abundance can be explained by climatic changes in the Arctic.     

Distribution of zooplankton in the estuary of Keretskaya Guba (White Sea)

The horizontal heterogeneity of common zooplankton species in the Keretskaya Guba tidal estuary in the White Sea was studied. Based on an analysis of a series of simultaneously taken samples and the dispersion index, I _w = σ²/[`(m)]bar{m} (where σ<sup>2</sup> is dispersion and [`(m)]bar{m} is average population number), the existence of two and more levels of aggregation in most of the studied zooplankton species was found. The formation of patches of 1–20 m was most likely determined by biological causes, while patches some hundreds of meters long were formed due to the hydrodynamic conditions of the area.     

Features of the Species and Spatial Structure of Macrobenthos in the Green Cape Lagoon (Kandalaksha Bay,White Sea)

Biology Bulletin - Abstract—Features of the species and spatial structure of sublittoral macrobenthic communities in a lagoon ecosystem of Green Cape (White Sea) have been studied. Thirty-one...     

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.     

Composition,diversity and distribution of microbenthos across the intertidal zones of Ryazhkov Island (the White Sea)

The composition and distribution of the main unicellular eukaryotic groups (diatom algae, ciliates, dinoflagellates (DF), other phototrophic (PF) and heterotrophic flagellates (HF)) were investigated in sandy sediments at five stations allocated across the tidal sheltered beach of the White Sea. Overall, 75 diatoms, 98 ciliates, 16 DF, 3 PF and 34 HF species were identified; some are new records for the White Sea. Common species for each group are illustrated. Diatoms and ciliates showed high alpha-diversity (species richness per sample), whereas flagellates were characterized by high beta-diversity (species turnover across the intertidal flat). Each group demonstrated its own spatial pattern that was best matched with its own subset of abiotic variables, reflecting group-specific responses to environmental gradients. Species richness increased from the upper intertidal zone seaward for ciliates but decreased for HF, whereas autotrophs showed a relatively uniform pattern with a slight peak at the mid-intertidal zone. Across the littoral zone, all groups showed distinct compositional changes; however, the position of the boundary between “upper” and “lower” intertidal communities varied among groups. Most of the species found at Ryazhkov Island are known from many other regions worldwide, indicating a wide geographic distribution of microbial eukaryotic species.