Approaches to marine biofouling control by thymol based paints

MIRIAM PÉREZ; MÓNICA GARCÍA; BEATRIZ DEL AMO; GUILLERMO BLUSTEIN; MIRTA STUPAK

Newcastle, United Kingdom

Congreso; 15th International Congress on Marine Corrosion and Fouling (15th ICMCF).; 2010

Comité International Permanent pour la Recherche sur la Préservation des Matériaux en Milieu Marin (COIPM)

A great quantity of natural products, most of which are found in marine organisms, has been extensively tested to assess their antifouling properties. Comparatively, little attention has been given to terrestrial plants in the search for natural products antifoulant. Essential oils of herbs and their components (secondary metabolism products) have many applications in ethno-medicine, food preservation as well as in the fragrance and pharmaceutical industries. Thymol, a natural compound isolated from essential oils of many plants (Thymus spp., Origanum spp., etc.), has been described as having useful pharmacological properties, with antifungal, antibacterial and antioxidative activities. In view of this, it was hypothesized that thymol would be potential inhibitor of the complex process of settlement of marine biofouling. The aim of this study is to evaluate the potential antifouling activity of a commercially available thymol on larval survival of Balanus amphitrite through laboratory antifouling bioassays and field trials. In the lab, it was evaluated the effect of thymol solutions ranged between 3.5 and 55mM. Toxicity test was conducted using nauplii II and results were recorded after 24 h incubation. Larval bioassays demonstrated a marked inhibitory and reversible effect. The values obtained for LC50 were 3.7 mM. For field trials, thymol was incorporated into a non-toxic soluble matrix paint. Acrylic panels coated with this paint were exposed in Mar del Plata harbour, Argentina. After six months exposure in the sea, thymol-based paint was effective in inhibiting settlement (p< 0.05 by ANOVA test using STATISTICA program). A great decrease in micro and macro-fouling density and diversity was observed in relation to controls (p<0.05 through ANOVA and contrast LSD test). The present study suggests that thymol could be employed as bioactive compound for antifouling paints.