Three UV treatments (PAR; PAR + UVA; PAR + UVA + UVB) were performed b
y placing different W-absorbing filters over communities developing on
ceramic tiles in a natural marine habitat near Korinthos, Greece, The
experiment was repeated at three depths (0.5 m, 1 m, 1.5 m) below the
surface of the sea, Differences in community structure due to UV radi
ation exposure were more pronounced during the early stages of communi
ty development. After the first 3 weeks of growth, the productivity of
the PAR + UVA + UVB treatment was significantly lower than the PAR UVA but not than the PAR treatment, This difference did not persist th
ereafter, At 5 weeks of growth, the productivity at 0.5 m was signific
antly lower that at 1.0 m, No other significant differences were obser
ved. The findings of the present study suggest that periphytic communi
ties occurring at the upper layers of the euphotic zone may be capable
of adjusting to changes in environmental stresses such as by increase
d solar UVB irradiance.