Influência dos nutrientes inorgânicos dissolvidos (NH4+, PO43-NO3-) na qualidade de água captada no canal do estuário dos Bons Sinais para ensaios experimentais de aquacultura no Chuabo Dembe

Abstract

Research focus on the influence of dissolved inorganic nutrients in the water quality pumped from Chuabo Dembe Channel to supply water to the aquaculture laboratory.The methodology consisted of determination of the topography of the channel, measurement of tidal height, salinity, dissolved oxygen, dissolved organic matter, temperature, velocity of currents, etc. Samples were collected one day in summer and one day in winter every hour. The results indicate nutrients concentration was high in summer with the following values: ammonium 5.55 mg/L, phosphate 4.5 mg/L and nitrate was 14 mg/L. Fluxes was high in high tide winter season. Fluxes recording were 123 g/s to ammonium; phosphate 149.5 g/s and nitrate were 315 g/s. And in relation to the physical-chemical parameters, average temperatures of 30.4ºC were observed in summer and 24.4ºC in winter, the dissolved oxygen had on average 5.7 mg/L observed in winter and 5.9 mg/L in summer. These results shows that the influence of dissolved inorganic nutrients and other water quality parameters measured in our research is within recommended standards for water quality to the experimental aquaculture. The flux was high from estuary toward the channel in both seasons. In summer the budget values was +764.8 g/s and it was +1336.1 g/sin winter, while overall and nutrients flux was + 1078 g/s.