Substâncias bioativas como inibidores de incrustação biológica

Abstract

Biofouling is the unwanted accumulation of organisms on submerged artificial surfaces. Biofouling causes great economic loss, as it increases the weight of vessels, making locomotion difficult, causes surface corrosion and is also an environmental problem, as it is a means of introducing invasive species. Natural products from some marine organisms have shown promise as antifouling agents. In this work, the antifouling efficiency of two marine sponges, Desmapsamma anchorata and Iotrochota arenosa (Demospongiae) was evaluated. Samples of these organisms, collected in Ilha Grande Bay, were subjected to chemical extraction with different organic solvents. The mucus produced by the sponges was also tested. The natural and doubled concentrations of raw extracts and mucus from sponges were evaluated in laboratory bioassays using Perna perna mussels. After approximately 14 hours of exposure to the treatments, the amount of byssal threads fixed both in the treatments and in the plates or mussel shells was counted. The amount of total byssal threads fixed in the different treatments were submitted to ANOVA (One Way) analysis. The treatments that showed to be most promising in the laboratory were also evaluated in a field bioassay, at the Clube Guanabara pier, in Guanabara Bay (BG), RJ. The extracts of D. anchorata inhibited the fixation of the byssal threads, unlike the sponge I.arenosa, which did not obtain a significant result. In the field, the different extracts of D. anchorata were placed in Petri dishes, and immersed in the BG water, an intersection point methodology was used to calculate the percentage of coverage. These bioassays occurred in summer and autumn, extracts from the sponge D. anchorata showed significant results in the analysis of PERMANOVA only in the summer season. During the field bioassay, seven different groups of marine organisms were found, biofilm, algae turf, Bugula neritina, Bugulina turbinata, Amphibalanus amphitrite and organisms from the Serpulidae and Spionidae families. The autumn fouling communities showed greater richness, diversity and evenness indices.