W10 PM Environmental Interactions of Marine Antifoulants
Wednesday, 16 November 2005: 1:50 PM - 5:30 PM in 341-342

(PET-1117-815123) Medetomidine - effects on physiology, community structure and functional diversity in algal and bacterial communities.

Petersson, C¹, Eriksson, M¹, Birgersson, G², Blanck, H¹, ¹ Göteborg University, Botanical Institute, Göteborg, Sweden² Lund University, Chemical Ecology & Ecotoxicology, Lund, Sweden

ABSTRACT- Medetomidine is as a new antifouling substance with prevention of barnacle fouling as main antifouling property. Medetomidine is an ₂-adrenoreceptor agonist that affect behaviour, growth and reproduction in mammals. Since this receptor is present in most marine fauna, medetomidine could affect more species than the target organism. Even though plants and microorganisms lack the ₂-adrenoreceptor studies are needed to avoid unforeseen environmental consequences. Short-term tests on microalgae and bacteria from epipsammon, phytoplankton and periphyton communities were performed to evaluate how medetomidine affect physiological characteristics. The parameters investigated were inhibition of photosynthesis and bacterial production. SWIFT, a semi-static test system, was used to investigate structural and functional changes in periphyton communities with pigment profiles, species composition and ECOplates^™ as evaluation tools. As a final investigation of medetomidines effects on the periphyton community a 3 week flow-through experiment were performed with both structural and functional end points. The results from the short-term and the semi-static tests show that medetomidine has limited effects on bacteria and microalgae. Inhibition of photosynthesis was low, 86% photosynthetic activity compared to controls in the highest concentration tested (10 M). Bacterial production was more sensitive with 75% production compared to controls at the same concentration. No structural or functional changes were observed for microalgae and bacterial communities. Results from the flow-through experiment are under evaluation. These results are part of a thorough hazard assessment of medetomidine effects in the environment. A substance with no negative effects on non-target organisms is a positive thing but for an antifouling substance it raises a question mark. Even though medetomidine is effective in preventing barnacle fouling, a satisfactory antifouling paint should prevent most fouling organisms, making more than one active substance necessary in the paint.

Key words: antifouling, ₂-adrenoreceptor agonist, algal and bacterial communities