Seasonal variations in physico-chemical parameters in Uppanar estuary, Cuddalore (southeast coast of India)

Seasonal variations of physico-chemical parameters such as rainfall, temperature, salinity, pH, dissolved oxygen and nutrients like nitrate, nitrite, inorganic phosphate and reactive silicate were studied from two different stations in Uppanar estuary, Cuddalore, southeast coast of India from April 2000 to March 2002. Atmospheric and surface water temperatures (°C) varied from 28 to 40.5 and 26 to 38 respectively. The salinity (‰), pH and dissolved oxygen (ml l) ranges were: 6.038.0; 7.1-8.2 and 2.4 to 4.5 respectively. Nutrient concentrations also varied considerably; nitrates: 8.15-25.66 μM, nitrites: 1.05-4.15 μM, phosphates: 0.17-2.96μM and reactive silicates: 27-168 μM. Nutrient concentrations were higher during monsoon season and low during summer.