Epibenthic communities in a marine shallow area with hydrothermal vents (Milos Island, Aegean Sea)

A quantitative study of sessile macroepibenthos was carried out in Palaeochori Bay (Milos Island, Aegean Sea) using underwater, framed, still photographs. Images of sessile epibenthos were collected from four different rocky shoals at 10-35 m depth: shoal CR, where continuous vent activity was evident, and shoals E, ST and S, without evident vent activity. At each site images were taken from four stations with different slopes. Three replicate photo-samples were collected at each station. Correspondence analysis showed that the distribution of epibenthic communities was mainly related to 'normal' environmental gradients such as slope, distance from the shore and depth. No clear, univocal effect of venting was recognized. However, small differences between the vent and non-vent sites were detected under overhangs, where vent effects could be locally amplified due to the entrapment of venting fluids.