Concentrations of ammoniac nitrogen, nitrite and nitrate in areas of oyster culture in Cananeia-SP, Brazil

DOI: 10.15343/0104-7809.20143801105115

Abstract

Nitrogen plays a key role in aquatic systems, especially in environments which are influenced both by marine and freshwater,
such as estuaries. The aim of this study was to evaluate aspects of water quality of Crassostrea spp. aquaculture sites in
Cananeia (SP, Brazil) and adequacy thereof for the cultivation of mollusks in relation to concentrations of total ammoniacal
nitrogen, nitrite and nitrate. Variations in concentrations of total ammoniacal nitrogen were 0.8 to 3.2 μmol/L, nitrite 0.1
to 3.2 μmol/L, and nitrate from 0.1 to 1.9 μmol/L. Analyzing these data in all seasons together, we found that average total
ammoniacal nitrogen and nitrite levels were significantly different for the tides and neap tide. These concentrations recorded
at Cananeia are similar to those observed for other estuarine tropical and subtropical regions of the world.