Evolution (1980-1990) of Ammonia and Dissolved Oxygen in Guanabara Bay, RJ, Brazil

by Helena P. Lavrado, Univ Estadual de Campinas, Campinas, Brazil,
Veronica Carvalho, Univ Estadual de Campinas, Campinas, Brazil,
Leticia M. Mayr, Univ Estadual de Campinas, Campinas, Brazil,
Rodolfo Paranhos, Univ Estadual de Campinas, Campinas, Brazil,



Document Type: Proceeding Paper

Part of: Coastal Zone '91

Abstract: The UFRJ is located on an island of Guanabara Bay and the Institute of Biology has been developing systematic studies on the bay. A synthesis of these studies and their different methodologies was published (Mayr et al., 1989 - CZ 89) in order to enhance the knowledge of this hydrology. It is a complex ecosystem surrounded by a densely urbanized and industrialized region. It is a typical coastal environment that is subjected to a fast process of degradation due mainly to domestic and industrial discharges. Water quality parameters are not uniform, due to the complexity of this ecosystem, establishing regions with different hydrological conditions. Results indicating a decrease in dissolved oxygen levels and increase in ammonia levels reinforce this knowledge. Nevertheless the bay can be divided into distinct regions, determined by differences in oxygen and ammonia trends. We have found that a very small area of the bay is ultimately responsible for the overall downward trend in water quality parameters. About 90% resists the antropogenic aggression, basically because of its auto-depurating potential. If preventive and corrective measures are taken in the near future, the situation should quickly be reversed.

Subject Headings: Dissolved oxygen | Bays | Ammonia | Water quality | Developing countries | Hydrology | Coastal processes | Ecosystems | Industries | Brazil | South America

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