UV effects on invertebrate and diatom assemblages of Greece

The effects of solar radiation (PAR, UVA,UVB) on the productivity and struc ture of diatom and invertebrate assemblages were assessed during primary su ccession on artificial substrate near a rocky shore of the Saronikos Gulf, Greece. Three light treatments were performed (PAR, PAR + UVA, and PAR + UV A + UVB) at 0.5, 1.0 and 1.5 m of depth. Pennate diatoms were the major com ponent of the developing periphytic communities during the study period. Ex posure to solar WE initially reduced the biomass and altered the structure of the diatom assemblages. The highest biomass of diatom assemblages was ob served under PAR (49.2 g/m(2)). This value was significantly higher than th e biomass of assemblages growing under PAR + UVA + UVB, but not significant ly different compared to the biomass of assemblages exposed to PAR + WA. Th ese differences, however, did not persist at later stages. The most abundan t invertebrate groups present were Polychaetes and Crustaceans. Solar UVB d id not have significant effects on invertebrate biomass, Analysis of the in vertebrate assemblage structure revealed time-course differences but no cle ar trends among the different treatments. (C) 2000 Elsevier Science S.A. Al l rights reserved.