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2N - Field Studies (MOP/136) Harbour pollution cause changes in macroalga community structure. Dahllöf, Ingela1, Dahl, Karsten1, 1 NERI, Roskilde, Denmark, Denmark ABSTRACT- Harbours are well known hot spots for pollutants ranging from heavy metals to an assortment of organic pollutants including anti-fouling substances. This study was aimed at investigating whether these hot spots cause changes in macroalga community structure, and if so, identify which alga that primarily are affected. Six harbours and six reference locations in Denmark were investigated. Care was taken to ensure that the reference area for each harbour had the same conditions with respect to physical disturbances, salinity, nutrient and light conditions. Macroalga were determined to species or group, and the level of coverage for each species/group was determined, along with total biomass of macroalga from each site. TBT in mussels from harbours and reference areas were used as an indicator for pollutant level. Similarity analysis showed that community composition in harbours was different from the reference area at all six locations. A large part of the difference between harbours and references was in all cases due to reduced cover of crust forming alga at the harbour sites with high TBT levels. Preliminary results also show lower total biomass in harbour areas. Results from this screening project suggest that contaminants from harbours can effect macroalga community composition. Key words: TBT, macroalga |
