ASSESSMENT OF SPATIAL AND TEMPORAL FLUCTUATIONS IN WATER QUALITY OF A TROPICAL PERMANENT ESTUARINE SYSTEM - TAPI, WEST COAST INDIA

A study pertaining to seasonal variation in physicochemical properties was carried out at five sites of Tapi estuarine zone for a period of one year i.e. July 2008 to June 2009. It revealed that the estuarine zone was significantly influenced by freshwater input during monsoon and post-monsoon periods. Concentration of all the nutrients and dissolved oxygen ( DO) was relatively high during the monsoon, whereas, and salinity were at their minimum level during this period. Phytoplankton production peak in terms of chlorophyll-a (Chl a) was observed in summer and winter during which a typical marine condition prevailed. In present study observed correlated values of salinity, nitrate, phosphate, silicate, values are significantly high in the estuarine zone. Cluster analysis carried out for both monthly and station-wise and average values gives different clusters depending on the affinity and relation between months and sites due to environmental conditions prevailed in the estuary zone. Principal Component Analysis (PCA) was used in the ordination of samples ( site, season and physicochemical parameters). The PCA was performed using all variables, Eigenvalues accounts and Scree plot showed that the first three Principal Components are the most significant components which represent more than 75% of the variance in water quality parameters in Tapi estuary, 48.5% by PC1, 14.4% by PC2 and 12.1% by PC3.