Produção Nacional
Ecological assessment of recent anthropogenic impacts on an estuarine ecosystem based on benthic diatom assemblages
2022; Elsevier BV; Volume: 52; Linguagem: Inglês
10.1016/j.rsma.2022.102294
ISSN2352-4855
AutoresFernando Oliveira, Angélica Yohana Cardozo, Doriedson Ferreira Gomes,
Tópico(s)Marine Biology and Environmental Chemistry
ResumoUntil recently, Camamu Bay (CB), a tropical estuarine ecosystem of the northeast coast of Brazil, state of Bahia, was considered pristine. However, an explosive regional economic growth is increasingly pressuring CB. We used the structure of diatom assemblages to determine whether this economic growth has impacted this habitat. We sampled water and sediment to determine the structure of diatom assemblages and measure physicochemical variables, including nutrients concentrations, salinity, pH, conductivity, temperature, redox potential, suspended particulate matter, dissolved oxygen, and granulometry at each of 30 sampling stations. We produced the percentage of the 11 eutrophication or organic pollution indicator taxa identified (namely Achnanthes fogedii, Bacillaria paxillifera, Cocconeis placentula, Cyclotella striata, Cyclotella stylorum, Halamphora coffeaeformis, Opephora marina, Paralia sulcata var. coronata, Paralia sulcata var. r adiata, Planothidium delicatulum , and Tabullaria waernii ) for each sample and we also determined the potential correlations of diatom taxa with the physicochemical variables. Our results revealed five distinct diatom groups determined by different combinations of variables reflecting the influence of natural and anthropic factors along the salinity gradient and that salinity exerted the strongest structuring effect on the assemblages. Higher presences of eutrophication indicator species were found near the central areas of the bay and in intermediate areas of Serinhaém and Maraú rivers. Planktonic taxa (e.g., Paralia sulcata) of occurring in the Marau River’s indicated high nutrients loading and uncommon hydrodynamic conditions. Our results suggest CB is undergoing a degradation process due to the economic activities. • Recent economic growth is pressing a previously considered pristine estuary. • Diatom community was sorted in five groups with different indicator taxa ratios. • Benthic diatoms assemblages were mainly structured by salinity. • Eutrophication is undergoing in the bay’s center and in Maraú and Serinhaém rivers. • The economic growth is increasing the environmental degradation in the estuary.
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