Natalia M. Kokryatskaya

On the elemental composition of suspended matter of the Severnaya Dvina River (White Sea region)

New data on the elemental composition of the Severnaya Dvina River, the largest one in the White Sea region, are presented. The elemental composition of the river water in May, the period of the snowmelt flood, is similar to the upper layer of the Earth’s continental crust due to the active erosion of the earth material in the catchment area. In August, the period of the summer low water, the impact of biogenic components increases and elevated concentrations of Cd, Sb, Mn, Zn, Pb, and Cu are observed. At other times, no significant pollution by heavy and rare-earth elements is registered.

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.

Seasonal biogeochemical and microbiological studies of small lakes in taiga zone of northwestern Russian (Arkhangelsk Province)

AbatractThe results of biogeochemical and microbiological studies of three small lakes in southwestern Arkhangelsk province are presented. The lakes differ in their morphometric characteristics, thermal and oxygen regimes, and the extent of anthropogenic impact they experience. In the periods of summer and winter stratification, anaerobic water layers with higher phosphates, ammonium, and sulfide sulfur (hydrogen sulfide) are found to form in the bottom horizon of deep-water zones of the lakes. The highest concentrations of sulfide sulfur (150–210 μg dm−3) were recorded in the shallow Beloe Lake during winter low-water period, while in summer, sulfide concentration did not differ from those obtained in other lakes (∼10 μg dm−3). The abundance of sulfate-reducing bacteria in lake bottom sediments varied from 10 to 100000 cell cm−3, and the rate of sulfate reduction process varied from 29 to 3746 μg S dm−3 day−1. Seasonal variations were revealed in hydrogen sulfide distribution over the water column and in the rate of sulfate reduction process in the upper horizons of bottom sediments in the examined lakes.

Dispersed Sedimentary Matter of the Atmosphere

In this chapter we summarize results of aerosol studies over the White Sea and its coasts; we also analyze contribution of different anthropogenic constituents from European industrial cities and areas into studied aerosol composition. We estimated the degree of anthropogenic influence of these sources on the atmosphere and the terrestrial environment in this region. Data on airborne heavy metal accumulation in natural archives (snow cover, lichens, lake sediments) are generalized. The most significant source regions for some anthropogenic components depositing on the White Sea surface from atmosphere are revealed. Annual average (for 2000s) fluxes of anthropogenic Cu, Ni, Pb, Fe, Al, and black carbon incoming to the White Sea waters from various regions are evaluated. Studied element concentrations in the White Sea aerosols are generally on the level typical for other Arctic regions. In the Kandalaksha Bay, we traced the air mass arrival from metallurgical facilities of Murmansk Region. Elevated concentrations of heavy metals and black carbon were found in vicinity of industrial urban agglomeration of Arkhangelsk. For the first time, we assess contribution of Kostomuksha field (Karelia Republic) surface mining into Fe and Al fluxes (these elements are of both lithogenic and anthropogenic origin) on the White Sea surface which are comparable to contribution of the other source regions.

Hydrological and Hydrochemical Characteristics of the Iron-Manganese Meromictic Freshwater Lake Svetloe (Arkhangelsk Region)

Received 12.01.2017, received in revised form 07.07.2017, accepted 26.10.2017, published online 01.02.2018 Meromictic lakes are a unique model for the study of the anaerobic processes of organic matter degradation, such as methanogenesis and sulphate reduction. As a result of activity of sulfate-reducing bacteria hydrogen sulfide accumulates in monimolimnion of these lakes, whereas chemocline is the area of sharp vertical gradients of physical and chemical conditions and as a consequence is the ecological niche for different planktonic microorganisms. This paper describes some characteristics of meromictic freshwater Lake Svetloe, located in the north of the Arkhangelsk region, for which ironmanganese type of meromixia was defined. The distribution of the studied parameters corresponds to the distribution of the specific for meromictic lakes water layers formed in the presence of stable stratification. In the transition layer (chemocline) a sharp decrease in the oxygen content (almost to the analytical zero) is accompanied by an equally sharp increase in the value of the water conductivity and the emergence of dissolved hydrogen sulfide in the water. In the anaerobic zone the conductivity values remain high and accumulation of nutrients, iron, manganese, and hydrogen sulphide (average 30 mg/l) occurs. Besides, the significant decrease in the content of dissolved sulphate caused by its consumption by sulfate-reducing bacteria was noted in this layer. The number of sulphate-reducing bacteria in the water column during the time of observation varied in the range of 10 – 106 cells/ml with the highest content in the chemocline zone, where the maximum amounts of hydrogen sulphide (up to 130 mg/l) were also found.

Sharp water column stratification with an extremely dense microbial population in a small meromictic lake, Trekhtzvetnoe: Sharp water column stratification

Located on the shore of Kandalaksha Bay (the White Sea, Russia) and previously separated from it, Trekhtzvetnoe Lake (average depth 3.5 m) is one of the shallowest meromictic lakes known. Despite its shallowness, it features completely developed water column stratification with high-density microbial chemocline community (bacterial plate) and high rates of major biogeochemical processes. A sharp halocline stabilizes the stratification. Chlorobium phaeovibrioides dominated the bacterial plate, which reached a density of 2 × 108 cell ml-1 and almost completely intercepts H2 S diffusion from the anoxic monimolimnion. The resulting anoxygenic photosynthesis rate reached 240 μmol C l-1 day-1 , exceeding the oxygenic photosynthesis rate in the mixolimnion. The rates of other processes are also high, reaching 4.5 μmol CH4 l-1 day-1 for methane oxidation and 35 μmol S l-1 day-1 for sulfate reduction. Metagenomic analysis demonstrated that the Chl. phaeovibrioides population in the bacterial plate layer had nearly clonal homogeneity, although some fraction of these cells harbour a plasmid. The Chlorobium population was associated with bacteriophages that share homology with CRISPR spacers in the host. These features make the ecosystem of the Trekhtzvetnoe Lake a valuable model for studying regulation and evolution processes in natural high-density microbial systems.

PROCESS OF SULFAT REDUCTION IN FRESHWATER LAKES (BELOE, NIZHNEE, SVYATOE) OF KONOSH DISTRICT OF ARKHANGELSK REGION

We consider the peculiarities of the process of sulfate reduction in three freshwater lakes with different anthropogenic impacts and groundwater types. Quantitative indicators of this process are presented. The results obtained are compared and the features of sulfate reduction in each of the reservoirs are highlighted. It is shown that the intensive sulfate reduction in water in summer is recorded for the most anthropogenically loaded lake. For a reservoir with the receipt of a sulfate type of groundwater, the process proceeds with the greatest accumulation of reduced sulfur compounds both in water and in bottom sediments.