Antifouling performances of eco-friendly secondary metabolite cocktails from marine plants

Attachment of micro and macro marine organisms onto an artificial surface is called as biofouling. Biofouling is a natural process and it can take place on any substrate surface. However, biofouling is a serious problem for the ships. As fouling organisms cover the hulls of the ships, they cause to increase of weight, reduction of speed, limitations in maneuverability, corrosion and high fuel consumption. In order to prevent biofouling, ship?s hulls are painted with special marine paints called as antifouling paints. Tributyltin (TBT) based self-polishing copolymer type antifouling paints were successfully used for prevention of fouling; but after their ban, a need for an eco-friendly and effective antifouling paint has been emerged. With respect to above mentioned needs, development of an eco-friendly biocide alternative to booster biocides was aimed based on secondary metabolite cocktails of marine plants both in laboratory and field tests in this thesis. According to results of acute toxicity tests, zosteric acid was not toxic to A. salina compared to other compounds tested. However, booster biocides (irgarol, diuron, copper and zinc pyrithione) and extracts of Zostera noltii and Cymodocea nodosa were decreased survival percentage of A. salina more than 50 percent at 185 mikrog/mL concentration. In the first field test, the surfaces of test panels were covered by micro-slime layer mostly composed of diatoms. In the second field test, macro-fouling organisms like serpulidae, bryozoans and tube worms were observed on paint free and primer coated test panels. Zosteric acid containing paint was covered by micro-slime layer but it was resistant against macro-fouling organisms for 90 days of test period. In conclusion, zosteric acid could be used in rosin based self-polishing antifouling paints not only solely but also as co-biocide or it could be modified to provide prolonged protection from fouling organisms.