Resumo A Bacia Hidrográfica do rio Bacanga (BHRB) apresenta problemas ambientais relacionados a urbanização e lançamentos de esgoto in natura que comprometem a qualidade desse ecossistema. Devido ao reduzido número de estudos associados à avaliação da qualidade da água no local, este estudo teve como objetivo avaliar a situação atual desse ecossistema por meio do Índice de Proteção da Vida Aquática. Seis amostragens bimestrais foram realizadas em seis pontos ao longo da bacia, coletando parâmetros físico-químicos para a aplicação do Índice de Estado Trófico e Índice de Parâmetros Mínimos para a Proteção da Vida Aquática, relacionando-os com a resolução Conselho Nacional do Meio Ambiente - CONAMA/357. Os resultados revelaram alterações significativas na qualidade da água da BHRB, o aumento de nutrientes e das concentrações de clorofila-a conduziram ao um estado geral de eutrofização. Os valores de surfactantes foram altos colocando em risco a biota aquática e as taxas de oxigênio dissolvido estiveram abaixo do permitido pela resolução na maioria dos pontos amostrados. A situação atual da qualidade da água para proteção da vida aquática é péssima em 61,92% dos pontos amostrados.

Abstract Bacanga River Basin faces environmental problems related to urbanization and discharge of untreated domestic sewage, which compromise its ecosystem health. Due to the small number of studies that assessed its water quality, the present study aimed to assess the current status of this ecosystem based on the aquatic life protection index. Samples were carried out every two months, in a total of six events, in six sites along the basin, where the water samples were collected to assess physicochemical parameters and calculate the trophic state index and the index of minimum parameters for the protection of aquatic communities. The data were also compared with values determined by the resolution National Environment Council - CONAMA 357/05. Our results reveal significant changes in the water quality of Bacanga River Basin. An increase in nutrients and chlorophyll-a concentration led it to eutrophication. The surfactant values were high and put in danger the aquatic biota. Dissolved oxygen rates were below the values allowed by the resolution in most sites sampled. The current water quality is terrible for the protection of aquatic life in 61.92% of the sites sampled.

Mangrove forests encompass a group of trees species that inhabit the intertidal zones, where soil is characterized by the high salinity and low availability of oxygen. The phyllosphere of these trees represent the habitat provided on the aboveground parts of plants, supporting in a global scale, a large and complex microbial community. The structure of phyllosphere communities reflects immigration, survival and growth of microbial colonizers, which is influenced by numerous environmental factors in addition to leaf physical and chemical properties. Here, a combination of culture-base methods with PCR-DGGE was applied to test whether local or plant specific factors shape the bacterial community of the phyllosphere from three plant species (Avicenia shaueriana, Laguncularia racemosa and Rhizophora mangle), found in two mangroves. The number of bacteria in the phyllosphere of these plants varied between 3.62 x 10(4) in A. schaeriana and 6.26 x 10³ in R. mangle. The results obtained by PCR-DGGE and isolation approaches were congruent and demonstrated that each plant species harbor specific bacterial communities in their leaves surfaces. Moreover, the ordination of environmental factors (mangrove and plant species), by redundancy analysis (RDA), also indicated that the selection exerted by plant species is higher than mangrove location on bacterial communities at phyllosphere.