We aim to evaluate the quality of the Guanabara Bay sediments and the ecological changes due to the PETROBRAS crude oil leak in January 2000. Twenty-six sediment samples collected in July 2000 and in February 2001 wer...We aim to evaluate the quality of the Guanabara Bay sediments and the ecological changes due to the PETROBRAS crude oil leak in January 2000. Twenty-six sediment samples collected in July 2000 and in February 2001 were analyzed for pH, dissolved oxygen, and foraminiferal composition. In the northwest and central parts of the bay, low oxygen dissolved values are related to waste discharges with the dominance of Buliminella elegantissima. In winter, near Iguaçu River, the pH of the sediment is low, therefore highly acidic. The acidity is responsible for the foraminiferal low diversity limiting the occurrence of species with fragile tests. On the other hand, thicker tests of Elphidium spp. disappeared last, therefore increasing its relative dominance in winter. In summer, this is a barren zone. The explanation lies in the continuous dissolution of tests that culminated with the total disappearance of these microorganisms one year after the accident.展开更多
文摘We aim to evaluate the quality of the Guanabara Bay sediments and the ecological changes due to the PETROBRAS crude oil leak in January 2000. Twenty-six sediment samples collected in July 2000 and in February 2001 were analyzed for pH, dissolved oxygen, and foraminiferal composition. In the northwest and central parts of the bay, low oxygen dissolved values are related to waste discharges with the dominance of Buliminella elegantissima. In winter, near Iguaçu River, the pH of the sediment is low, therefore highly acidic. The acidity is responsible for the foraminiferal low diversity limiting the occurrence of species with fragile tests. On the other hand, thicker tests of Elphidium spp. disappeared last, therefore increasing its relative dominance in winter. In summer, this is a barren zone. The explanation lies in the continuous dissolution of tests that culminated with the total disappearance of these microorganisms one year after the accident.
