Plankton as a Factor Modifying the Physical Characteristics in the Marine Environment

Abstract. Some hydrophysical environmental parameters ( e.g . temperature, salinity, transparency, flows, erc .) are known to profoundly affect the structural and functional characteristics and species composition of plankton communities. The purpose of the present work was to assess the opposite - the influence of qualitative and quantitative characteristics of plankton on some optical (light transmission. optical density) and acoustic (sound volume backscattering strength) characteristics in the Black Sea. The influence of specific features (shape, size and color) of planktonic unicells on light attenuation in seawater was examined in laboratory experiments. The data from field studies on variability of statistic characteristics of sound volume backscattering strength in upper productive water layer, depending on species composition and numbers of zooplankton, are given.