Biological, Chemical And Hydrological Characters Of Coastal Lagoons Of Ghana, West Africa
Published 1977 · Biology
Two types of lagoon which occur along the West Coast of Africa described as ‘open’ and ‘closed’, were studied using oceanographic methods. The parameters were temperature, salinity, dissolved oxygen and productivity. It was observed that rainfall, evaporation and the tides have a combined effect on the variations in the temperature and the salinity. The opening of the lagoons into the sea affects the level of the productivity and the rate at which salinity increases with time.Minimum temperatures at the heads of the lagoons were found to be lower than those near the ocean, while the maximum temperatures were higher at the heads. During the dry period, due to continuous evaporation of water, the salinity in the ‘closed’ lagoon usually rises steeply, while those in the ‘open’ lagoon rise gently.The levels of dissolved oxygen concentration in the ‘open’ lagoon are higher than those in the ‘closed’ lagoon. This is the result of the fact that phytoplankton count in the open lagoon is higher than that in the closed lagoon. There is also a greater diversity of phytoplankton and more live phytoplankton cells per cubic centimetre of water in the open lagoon than in the closed lagoon.As a result of all this, the main organic productivity in the open lagoon is higher than those in the closed lagoon.