Diel and tidal fluctuations in the water quality of Vasishta Godavari estuary

Abstract

Diel and tidal fluctuations of selected physico-chemical factors (water temperature, K value, salinity, density, dissolved oxygen and inorganic nutrients - phosphate, nitrite and silicate) in the middle reaches of Vasishta Godavari estuary during the recovery (November 1981), stable (February 1982) and drought (May 1982) phases were studied. Diel and tidal fluctuations in water temperature were negligible. Diel fluctuation of salinity at the bottom was considerably less than that at the surface, while dissolved oxygen exhibited the same trend both at the surface and the bottom. Among inorganic nutrients, fluctuations in phosphate and silicate were marked at the surface than at the bottom. Fluctuations in salinity and silicate were tide-linked, unlike those of others. Water close to the bottom in Vasishta Godavari estuary was found to provide more uniform living conditions than that in its sister distributary, the Gautami Godavari.