BIOLOGIYA MORYA, 2010, Vol. 36, No. 3, pp. 186-195

Production and hydrochemical characteristics of ice, under-ice water and sediments in the Razdolnaya River estuary (Amursky Bay, Sea of Japan) during ice cover period

© 2010 V. I. Zvalinsky¹, À. À. Ìaryash¹, I. V. Stonik², M. G. Shvetsova¹, S. G. Sagalaev¹, A. A. Begun², P. Ya. Tishchenko¹

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

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Production and hydrochemical characteristics of ice, under-ice water, and sediments in the Razdolnaya River estuary (Sea of Japan) were studied during ice cover periods of the years 2007 and 2008. In 2007, snow cover was absent until mid-February and PAR levels under ice were sufficient for the development of phytoplankton. Chlorophyll α content in ice, under-ice water, and surface sediments was high, while nutrient levels were decreased. After snowfall, chlorophyll content in ice and under-ice water decreased sharply. In winter 2008, snow cover was formed immediately after freeze-up; therefore, PAR levels in ice and under-ice water were significantly reduced. Chlorophyll content was lower, but nutrient levels were higher than in 2007. In both winter seasons, the greatest portion of chlorophyll (up to 85%) was contained in surface sediments. Diatoms were dominant in ice and under-ice water. In the absence of snow, primary production at the end of ice cover period may reach 1 g C/(m² day). With snow cover present, this index was markedly reduced.

Key words: ice cover, bottom sediments, nutrients, chlorophyll, phytoplankton, primary production, estuary.