Relações tróficas no Complexo Estuarino de Paranaguá, Paraná (CEP/PR) e na Baía de Ilha Grande, Rio de Janeiro (BIG/RJ) e bioacumulação de compostos organobromados no boto-cinza, Sotalia Guianensis (Van Beneden, 1864) (Cetacea, Delphinidae) do CEP/PR

Abstract

Carbon ( 13C) and nitrogen ( 15N) stable isotopes ratio approach have become an important tool in ecological studies, allowing a better understanding of trophic relationships within an ecosystem. 15N values, it is possible to access an organism trophic level in their food chain and usually top predators, such as marine mammals, have high concentrations of several chemical contaminants in their tissues. Therefore, this study aimed to investigate trophic relationships in the food webs of Paranaguá Estuarine Complex, Paraná (PEC/PR) and Ilha Grande Bay, Rio de Janeiro (IGB/RJ) and to verify organobrominated compounds bioaccumulation in Guiana dolphins (Sotalia guianensis) from PEC/PR. This thesis was divided into two sections. In the first section, trophic relationships in Guiana dolphins food webs from PEC/PR and IGB/RJ were analyzed using carbon and nitrogen stable isotopes; in the second section organobrominated compounds concentrations in Guiana dolphins muscle from CEP/PR were investigated. In PEC/PR, there was a variation in 15N 13C values from seston between seasons (winter/summer). Nitrogen stable isotopes mean values in Guiana dolphins preys ranged 13C values ranged from - -15, 15 13C mean values found in Guiana dolphins from PEC/PR were 13,6 and -16,4 , respectivelly. In IGB/RJ, a statistically difference between seasons 13C values found in seston. 15N values in Guiana dolphins preys varied from 10,9 2 13C values ranged from -19,7 -15,3 Mean values 15 13C in Guiana dolphins from IGB/RJ were 14,2 and -16,5 , respectivelly. Concerning organobrominated compounds concentrations, the results found in Guiana dolphins muscle varied from 6,73 ng/g lip. to 381,81 ng/g lip. (anthropogenic compounds) and from 15,82 ng/g lipid. to 759,64 ng/g lip. (naturally produced compounds). All Guiana dolphins analysed here showed a greater contribution of naturally produced organobrominated compounds than anthropogenic compounds. Males showed higher concentrations of organobrominated compounds, both natural and anthropogenic, than females. Juvenile females presented total concentrations of organobrominated compounds higher than adult females.