Effect of diffuse and point source nutrient supply on the low diverse macrozoobenthic communities of the northern Baltic Sea

Soft bottom macrozoobenthic communities from the coastal sea area of Helsinki (south Finland) and Saaremaa Island (west Estonia) were compared in order to evaluate the effects of diffuse and point source nutrient supply. The coastal sea area of Helsinki receives a moderate load of municipal sewage water and the latter is ranked among the most undisturbed ecosystems in the northern Baltic Sea. The species composition and dominance structure were similar in both the studied areas indicating that different sources of eutrophication (i.e. local or basin wide) have similar consequences for the macrozoobenthic communities. However, functional diversity was higher in the Saaremaa area as the higher share of herbivores and suspension feeders were found in the area.