Ecology, Environment and Conservation Paper

SEASONAL VARIATIONS OF HYDROGRAPHIC PARAMETERS OFFTHE CHENNAI COAST, INDIA

P. Hemasankari, D. Prema, Kaladaran and Vasanth Kripa

Abstract

The environment plays a major role in determining the abundance of fishes in a particular region and ithelps to predict the probable fishing zone. This environment variables includes temperature, salinity, pH,TSS, DO(Dissolved Oxygen), chlorophyll a, b and c, primary productivity, gross and net, nutrients,phosphate, nitrate and ammonia. These parameters were estimated using standard procedures. Theseparameters in a particular fishing zone varies from season to season. This seasonal variations of theseparameters and its relationship with each other are studied in Ennore, (Lattitude, 80°19’31"E, and Longitude,13°14’51"N). an industrially polluted area along Chennai coast. Factor analysis is done to remove theredundant highly correlated variables from the data, replacing the entire data with uncorrelated variables.During the post monsoon season, the 4 components extracted by factor analysis indicates that the nutrient,nitrate, chlorophyll b, TSS and dissolved oxygen are important variables deciding thephotosynthetic activity,in summer season, 3 components were extracted and the variables that decide photosynthetic activity includesnutrient nitrate, temperature and nutrient ammonia. In pre-monsoon season, 5 components were extractedby factor analysis and the deciding variables include pH, chlorophyll, c, chlorophyll a, chlorophyll b andsalinity. In monsoon season, 3 components were extracted and the deciding variables include TSS, DO andtemperature for the photosynthetic activity to take place. The eigen values worked out in all the4 seasonsare above 1 and are reliable. The eigen value is highest in the post monsoon component tested, 4.39 and theleast eigen value, 1.05 is in the pre monsoon season. Pre monsoon season among all seasons shows highestpercentage of cumulative variance. In the post monsoon season, the variables N-Nitrate, chlorophyll b, TSSand DO in the components 1, 2, 3 & 4 decide the growth of phytoplankton with 12% loss ofinformation. Inthe summer season, the variables, N-Nit, temp., and N-amm., in the components 1, 2 and 3 are the decidingfactors for the growth of phytoplankton with 26% loss of information. In the post monsoon season, thevariables, pH, chlorophyll c, chlorophyll a, chlorophyll b and salinity in the components, 1, 2, 3, 4 and 5respectively decides the phytoplankton growth with 11% loss of information. In the monsoon season, thevariables, TSS, DO and salinity in the components 1, 2 and 3 decide the growth of phytoplankton with 22%loss of information. These variables are representative of all original 11 variables and the components arenot linearly correlated with each other. The size of the data from 11 variables can be reduced tothreecomponents by using factor analysis with the principal components extraction.