Grau de estratificação da coluna de água na baía de Maputo

Abstract

The present work consisted in the determination of the potential energy anomaly along the section A in the Maputo bay as a way to evaluate the energy necessary to completely mix the water column, a mixture that becomes an important condition for the dynamics and primary productivity in the bay . The potential energy was determined based on the density data collected in the section under study, over a period of ten months (starting in October 2003) covering the winter and summer seasons. The results indicated that the bay was, for most of the study period, mixed with an energy deficit of 7.3%. The most stratified time of the year was the last months of summer (February and March) and the first month of winter (April). The mixture is due to the shallow depth of the bay, reduced lift forces and relatively strong tidal currents, while stratification is mainly promoted by the discharge of fresh water. Considering tides as the sole contributor to the water column mix, the minimum energy required to mix the entire water column was 138.5 Jm-3.