Affiliation: | aPrograma Zona Costeira, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro/MMA, Rua Pacheco Leão 915, 22460-030 Rio de Janeiro, RJ, Brazil bDepartamento de Biologia Animal e Vegetal—Rua São Francisco Xavier 524, PHLC Sala 220, Setor de Ecologia, 20559-900 Rio de Janeiro, RJ, Brazil cLaboratório de Biomineralização, Departamento de Histologia e Embriologia, ICB, UFRJ, 21941-590 Rio de Janeiro, RJ, Brazil dLaboratório de Radioisótopos Eduardo Penna Franca, Instituto de Biofísica Carlos Chagas Filho, CCS, UFRJ, 21949-900 Rio de Janeiro, RJ, Brazil |
Abstract: | Metal concentrations and population parameters of the seagrass Halodule wrightii were determined at three locations at Rio de Janeiro State, Brazil. The possible increase of metal availability in one of these areas, Sepetiba Bay, as a result of dredging of contaminated bottom sediments which ocurred, was evaluated by analyses of Al, Cd, Cr, Cu, Fe, Ni, Pb and Zn in root, rhizome and shoots. In addition, analyses were carried out in H. wrightii populations from non-contaminated areas located at northwestern (Cabo Frio) and southeastern (Angra do Reis) regions of Rio de Janeiro State. Concurrently, abundance and density data of the seagrass populations were obtained. It was found that concentration from Sepetiba Bay samples up to 1.6 ± 0.4 μg g−1 of Cd, 12 ± 1.0 μg g−1 of Cr, 27 ± 2.4 μg g−1 of Pb, 291 ± 47 μg g−1 of Mn, 128 ± 23 μg g−1 of Zn were significantly higher than that from two other collection sites. An increase in Cd and Zn concentration was observed in H. wrightii from Sepetiba Bay indicating that metal mobilization from contaminated sediments through dredging activities were, at least in part, transferred to the biotic compartment via accumulation by the seagrass. The populations of seagrass within the region demonstrated quite substantial changes in biomass data but not in shoot or rhizome density during the study. Such changes in biomass are to be expected, as these dynamics are typical of the small, isolated monospecific populations of H. wrightii along the Rio de Janeiro coast. |