Physical oceanographic behavior at the Guamá/Acará-Mojú and the Paracauarí river mouths, Amazon Coast (Brazil)

Abstract

This paper focuses on the physical oceanographic behavior at the mouth of two tributary systems of the Para River, on the Brazilian Amazonian Coast. The Guamá/Acará–Moju Rivers are connected to the right margin of the Pará River through the Guajará Bay. The Paracauari River is a smaller system, and is connected to the Para along its left margin, via the Marajó Bay. The purpose was to characterize the physical oceanographic behavior at those areas and contribute to emergency contingency actions in occasional accidents related to oil spills. Fieldwork was carried out in the dry season, at the lowest expression of continental drainage and comprised measurements of water temperature, salinity and currents speed and direction; measurements of near surface wind intensity and direction, and the gathering of records of the tidal oscillation. The Guamá/AcaráMoju was classified as type 1b and the Paracauari as type 1a by the Hansen and Rattray classification criteria. In the most inland location, higher fresh water input and greater depth contributes to increase stratification in the system. Distinct hydrodynamical behavior distinctly affects residence time, concentration and transport of foreign substances released into the estuarine environment, and will require specific management