Distribution of Cs in benthic plants along depth profiles in the outer Puck Bay (Baltic Sea).

A study was conducted on three macroalgae species: and , the species of the red algae division, and , representing the green algae division, as well as , representing vascular plants. The main aim of the study was to recognize the level of Cs concentrations in the plants, which could be used as a measurement of bioaccumulation efficiency in the selected macrophytes at varying depths, and in the seasonal resolution of the vegetation period: spring-summer and autumnal. The plants' biomass clearly showed seasonal variability, as did the Cs concentrations in the plants. Cesium activity also changed with depth. Seasonal variability in radionuclide content in the plants, as well as the differences in its activity determined along the depth profile, were related mainly to the plant biomass and the dilution effect caused by the biomass increment and reflected the growth dynamics. showed much greater bioaccumulation ability at each depth as compared to , a green algae. Lower concentrations of Cs were also identified in and in mostly as a result of differences in morphology and physiology. can be recommended as a bioindicator for the monitoring of Cs contamination due to the high efficiency of bioaccumulation and the available biomass along the depth profile, as well as the occurrence throughout the entire vegetation season.