Monthly fluctuations of physico-chemical characteristics marine water samples were carried out in Pazhayar, Kollidam Taluk, Nagapattinam District, Tamil Nadu India, for a period of twelve months (January 2017 to December 2017). Eight various physico-chemical parameters were analyzed by using standard methods (APHA, 1998). Water temperature varied from 26.12 to 28.97°C, Dissolved oxygen content varied between 4.53 to 5.53 mg/L, salinity (27.09 to 28.53 ppt), pH ranged from 6.33 to 7.82. Phosphate varied 6.38 to 7.73mg/L, Nitrate (0.74 to 1.87 mg/L), silicate (10.27 to 11.78), calcium (407.75 to 678.78 mg/L), magnesium was from 217.5 to 482.97 mg/L, and chloride (12.60 to 14.91 mg/L) also varied independently.
