Current State of Heterotrophic Bacterioplankton and Bacteriobenthos in the Northern and Middle Parts of the Caspian Sea
Abstract
Data on the abundance of heterotrophic bacterioplankton and bacteriobenthos in the northern and middle parts of the Caspian during the period from 2013 to 2017 are presented. In the waters of the northern part of the Caspian, a peak in the number of saprotrophs and crude oil degraders was recorded in 2013. In the middle part of the Caspian and in the region of the Mangyshlak regression, high numbers of heterotrophic bacteria were recorded in 2013 and 2016. The biodiversity of bacterioplankton in the surveyed areas is almost the same; the species composition of saprotrophs and crude oil degraders is identical. In the bottom sediments of the northern and middle parts of the Caspian Sea, two peaks of saprotrophic bacteriobenthos development (in 2013 and 2016) were recorded; in the region of the Mangyshlak threshold, the concentration of saprotrophs remained stable. The number of crude oil degraders was inferior to those of saprotrophs, while the proportion of crude oil degraders to saprotrophs changed annually. The species composition of saprotrophs is relatively stable, the biodiversity of oil-oxidizing bacteriobenthos has changed in the direction of increasing the proportion of non-fermenting bacteria. Constant changes in the ratio of the number of saprotrophs and crude oil degraders, together with the transformations of the dominant groups of the species composition of bacteria, indicated the instability of bacteriobenthos, and, as a result, the vulnerability of the microecosystem of bottom sediments under changing environmental conditions.
References
[1] Tuzhilkin, V. S., Kosarev, A. N., Arkhipkin, V. S., Nikonova, R. E. (2011) Long-term variability of the hydrological regime of the Caspian Sea in connection with climate variations. Bulletin of Moscow University. Series 5. Geography, No. 2, pp. 62–71.
[2] Katunin, D. N. (2014) Hydroecological basis for the formation of ecosystem processes in the Caspian Sea and the delta of Volga river. Astrakhan: Publishing House of CaspNIRKh.
[3] Huseynov, K. M., Hasanova, A. Sh., Huseynov, M. K. (2015) Some information on the hydrological and hydrochemical regime of the Dagestan sector of the Caspian. South of Russia: ecology, development, No. 2, pp. 136–145.
[4] Stoloviy, D. E. (2011) International cooperation in the conservation of aquatic biological resources of the Caspian Sea. Bulletin of the ASTU. Series: Fisheries, No. 2, pp. 56–62.
[5] Monakhova, G. A., Abdurakhmanov, G. M., Murzakanova, L. Z. (2009) Ecological features of the Caspian Sea regions with different legal and economic regimes. South of Russia: ecology, development, No. 3, pp. 85–90.
[6] Kolotova, O. V., Sokolova, I. V., Vladimtseva, I. V., Shmeleva, E. O., Vodovsky, N. B. (2017) Bacterial communities of the pelagic and bottom sediments of the Northern Caspian in 2015-2016. South of Russia: ecology, development, No. 4, pp. 120–137.
[7] Patin, S. (2017). Oil and the ecology of the continental shelf: in 2 vols., 2nd ed. revised and supplemented. V. 2: Environmental impacts, monitoring and regulation during the development of shelf hydrocarbon resources. Moscow, M: Publishing House of VNIRO.
[8] Netrusov, A. (2005). Workshop on microbiology. Moscow, M: Akademia.
[9] Ineshina, E. G., Gomboeva, S. V. (2006). Guidelines for a laboratory workshop on the courses “Sanitary Microbiology”, “Sanitary and Microbiological Control at Work”. Ulan-Ude, Publishing House of VSSTU.
[10] Holt, J. (1997). Bergey‘s Manual of Determinative Bacteriology In 2 vols. Moscow, M: Mir Press.
[11] Dyakova, S. A., Galyautdinova, E. R., Lardygina, E. G. (2018). Current state of the microecosystem of the North Caspian. Bulletin of the Astrakhan State Technical University. – Series: Fisheries, No. 4, pp. 30–38.
[12] Serebrennikova, E. A., Dyakova, S. A. (2017). Integrated oceanographic survey of the North and Middle Caspian at the Caspian Researcher research vessel in June 2016. Oceanology, vol. 25, No. 3, pp. 532–533.
[13] Ivanov, M. V., Savvichev, A. S., Klyuvitkin, A. A., Zakharova, E. E., Rusanov, I. I., Lein, A. Yu., Lisitsyn, A. P., Chul’tsova, A. L. (2013). Resumption of hydrogen sulfide contamination of the water column of deep basins in the Caspian Sea. Doklady Earth Sciences, vol. 453, No. 1, pp. 1094–1099.
[14] Lartseva, L. V., Obukhova, O. V. (2010) Natural foci of sapronoses in the hydroecosystem of the Volga- Caspian region. Bulletin of the Samara Scientific Center of the Russian Academy of Sciences, No. 1–8, pp. 2137–2139.
[15] Obukhova, O. V., Lartseva, L. V. (2013). Biohazard due to natural focal sapronoses in the hydroecosystem of the Volga-Caspian basin. Astrakhan Journal of Environmental Education, No. 1(23), pp. 133–136.