Copper chloride (II) effect on the composition and structure of marine microphytobenthic communities

To assess the temporary effects of the increased copper ion inflow on estuarine microphytobenthic communities, ecotoxicological tests were conducted using natural microphytobenthic assemblages obtained from an artificial substratum exposed to the waters of the southern Baltic Sea (Gulf of Gdańsk). The applied copper ion concentrations reflected permitted copper values established for waters of a good ecological status (2·10^-5 g Cu·dm^-3), and the maximum copper concentrations which, according to the current environmental regulations, are allowed to be discharged into the environment (2·10^-3 g Cu·dm^-3).In the studied communities, diverse responses of single species to CuCl₂ exposure were recorded, including both growth inhibition and stimulatory effects as well. Despite the shift in the community composition and structure, total cell number remained at a similar level. The results of our investigations suggest that microphytobenthic assemblages are resistant to CuCl₂ which is facilitated by the shift in the community composition resulting from the increasing cell number of copper tolerant species.