Microbial processes in the Kanda Bay, a meromictic water body artifically separated from the White Sea.

Sings of meromixis are found by means of microbiological and biogeochemical investigations in the southernn part of the Kanda Bay, an artificial water body separated front the White Sea with a railway dam. The concentration of oxygen in the bottom layer attained 1.9 mmol/L, intensity of the process of microbial sulfate reduction, 3.0 µmol of sulfur/(L day). The concentration of dissolved methane, 3.7 µmol/L. Isotopic composition of carbon in methane (δ13C (CH4) =-79.2‰) indicates to its microbial genesis. At present, Kanda Bay is a sole in Russia man-made marine water body for which there are data on the rate of microbial processes responsible for formation of bottom water layer containing hydrogen sulfide and methane.

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 predom- inance of the brown GS B forms and the changes ratio of the species of purple sulfur bacteria (PS B) in anoxic water layers. Production of anoxygenic photosynthesis in the lake was at least 240 mg C m-2 day-- in September and 0-20 mg C m-2 day- 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 Thiocapsapendens DSM.236 and Thiocapsa bogorovii BBS, as well as with the strains AmPS10 and TcyrPS 10, which were isolated from Lake Kislo-Sladkoe in 2010.

[Cryptomonad alga Rhodomonas sp. (Cryptophyta, Pyrenomonadaceae) bloom in the redox zone of the basins separating from the White Sea].

Bloom of a cryptomonad alga Rhodomonas sp. (Cryptophyta, Pyrenomonadaceae) was observed in the chemocline of saline basins separating from the White Sea, resulting in red coloration of the relevant water layer. According to the sequence of the 18S nuclear rRNA gene, this species was identical to Rhodomonas sp.RCC2020 (GenBank accession no. JN934672) from the Beaufort Sea. The presence of the red layer formed by mass development of Rhodomonas sp. is considered as an indicator of a certain stage of separation of a basin from the sea.