Seasonal variations in physico-chemical characteristics of Pichavaram mangroves, southeast coast of India.

All the physico-chemical parameters such as temperature, salinity pH, dissolved oxygen and nutrients like nitrate, nitrite, inorganic phosphate and reactive silicate were studied in Pichavaram mangroves, southeast coast of India, for a period of two years (April 2000-March 2002). Air and surface water temperatures varied from 27 degrees C to 38 degrees C and from 26 degrees C to 37 degrees C. Salinity varied from 3.0 per thousand to 33.0 per thousand and the pH ranged between 7.2 and 8.2. Variation in dissolved oxygen content was from 2.4 to 5.0 ml l(-1). Concentrations of nutrients viz nitrates (9.50 to 32.12 microM), nitrites (1.07 to 5.99 microM), phosphates (0.73 to 2.36 microM) and reactive silicates (22.1 to 89.8 microM) also varied independently.