Structure of phytobenthic and associated animal communities in the Gulf ofRiga

Within the Gulf of Riga Project, phytobenthic and associated animal communi ties were sampled in 1995 and 1996 using SCUBA techniques. The aim was to q uantitatively describe the phytobenthic communities and their distribution and to evaluate the present status of the phytobenthos in comparison to ear lier investigations, as well as its contribution to the ecosystem of the Gu lf as a whole. Classification and ordination analysis showed differences am ong the different areas of the Gulf of Riga, where Saaremaa, the Parnu area and the middle and the inner part of the Gulf formed distinctive groups. T he inner part and the Parnu Bay area are influenced by the nutrient and pol lution load of mainly the rivers Parnu and Daugava. The intermediate wester n and eastern coasts of the Gulf of Riga, as well as the northern coasts al ong the island of Saaremaa seem to hold phytobenthic communities of compara ble composition and biomass found elsewhere in clean areas of the Baltic Se a.