BIOLOGIYA MORYA, 2013, Vol. 39, No. 2, pp. 85-97

Phytoplankton of Amur River Estuary (Sea of Okhotsk) during the summer periods of 2005-2007

© 2013 O. G. Shevchenko¹, M. S. Selina¹, T. Yu. Orlova¹, T. V. Morozova¹, I. V. Stonik¹, V. I. Zvalinsky², P. Ya. Tishchenko²

¹A.V. Zhirmunsky Institute of Marine Biology, Far East Branch, Russian Academy of Sciences, Vladivostok 690059;
²V.I. Ilyichev Pacific Oceanological Institute, Far East Branch, Russian Academy of Sciences, Vladivostok 690041

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This study deals with the qualitative and quantitative composition of planktonic microalgae in Amur River Estuary (the Sea of Okhotsk) in July 2005, June 2006, and June 2007. The biomass and abundance of phytoplankton were studied for the first time. The average cell density of microalgae ranged from 194.7 thousand to 855.1 thousand cells/liter, being higher in 2006 than in 2005 and 2007. The average biomass of the community varied from 1.06 g/m³ in 2007 to 3.17 g/m³ in 2006. Analysis of the similarity of species composition and cell density of phytoplankton revealed two groups of stations: the first including stations in the northern and central parts of Amur River Estuary and the second with stations in the southern and central parts. The first group was characterized by the predominance of freshwater diatoms and high abundances of green and blue-green algae; and the second, by the predominance of marine microalgae. The high cell density and biomass of phytoplankton were due to the increased nutrient input via the Amur River flow.

Key words: phytoplankton, microalgae, salinity, temperature, nutrients, chlorophyll, Amur River Estuary, Sea of Okhotsk, Sea of Japan.