Colonização de organismos incrustantes em diferentes tipos de substratos artificiais na Baía de São Marcos, São Luís - MA

Abstract

This study had as objective to invertigate the occurrence of fouling organisms in diferente types of substrates the area of São Marcos Bay, under port influence. For the study, three sampling points were defined, which were accessed on four dates between the periods of December/2020 to September/2021, quarterly. The specimens were sampled with recruitment panels composed of four different substrates (acrylic, polyethylene, metal and wood). In situ abiotic variables were also measured, in order to understand the communities tolerances. Appraising the average values of the abiotic parameters, it was observed that there were no significant differences between the stations sampled, except for the metals: boron, copper and zinc with their respective values (p-value = 0.04; 0.004 and 0.015). The values (mg/L) obtained for all metals are above the recommended by CONAMA Resolution no 357/2005. Tukey's test revealed that density was higher in P1 than in P2 and P3, while equity was significantly lower in P1 compared to the other areas. The richness in metal and wood substrate were significantly higher than that found in polyethylene. The non-metric multidimensional analysis (nMDS) showed a grouping in the density of species at point P1, however for the substrates it did not show an ordering of densities, showing few comparisons of efficiency between substrates and a good balance of similarity at P2. The Canonical Correspondence Analysis (CCA) explained 92.12% of the observed data in the add of the two axes, revealing that the zinc concentration negatively influenced four species in P1. Three taxa represent new records for Brazil, namely: Lagis sp., (Polychaeta); Cerapus cf. bumbumiensis (Amphipoda); Natica cf. vitellus (Gastropod) that need to have their studies expanded to determine whether their occurrences indicate bioinvasion events. Studies reveal that chemical components may be influencing the density of encrusting organisms in P3. Therefore, the results of this study indicate that the anthropic processes generated by the port complex influence the distribution of native diversity, as well as attracting exotic species through port activities.