Studies on oceanographic conditions of the surface and bottom waters of the Bay of Bengal off Visakhapatnam during 1968-1972

The inshore hydrographic data in the region off Waltair for the period from October 1968 to March 1972 were observed in order to study the seasonal variation of temperature, salinity, dissolved oxygen content, phosphate and silicate. Salinity showed lesser variation at bottom than at surface. Changes of salinity from maximum to minimum and vice versa were quite rapid with a minimum in October and a steady maintenance in the maximum for a long period from April to July. Temperature variation gave rise to double maxima and double minima in the annual trend. Bottom waters showed consistantly higher values than surface with a maximum during September-October. Phosphates indicated two maxima, one during onset of monsoon and another during winter. Silicates showed a steady increase from January to December during 1971