2014•MicrobiologyRequires access
Microbiological and biogeochemical properties of the Caspian Sea sediments and water column
Alla Yu Lein, А. С. Саввичев, М. Д. Кравчишина, N. V. Kozina, V. I. Peresypkin, E. E. Zakharova, E F Veslopolova, I. N. Mitskevich, N. A. Shulga, Н. В. Лобус, Н. В. Политова, Mark V. Ivanov
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Abstract
The work presents the results of investigation of microbial and biogeochemical processes at the water-sediment interface in the samples of three Caspian Sea profiles obtained during the 39th cruise of RV “Rift” in May–June 2012. The decrease in suspended C org content from the surface to the bottom resulted from the activity of aerobic heterotrophic microorganisms. Autotrophic methanogenesis occurred in anoxic water of deep-sea depressions, where methane concentrations were up to 2.2–3.75 μL CH 4 L −1 , which was an order of magnitude higher than in the aerobic water column (0.04–0.32 μL CH 4 L −1 ). Methanogenesis was accompanied by a considerable decrease in δ 13 C of suspended C org (−26 to −30‰). The numbers of microbial cells in the water column varied from 40 to 3200 × 10 3 cells mL −1 . The results of microbiological and biogeochemical investigation demonstrated that, in spite of the absence of connection with the ocean and other specific features, the Caspian Sea has the characteristics of a typical marine basin.