Studies of Phytoplankton Diversity from Agnitheertham and Kothandaramar Koil Coastal Waters; Southeast Coast of India

Totally 68 species of phytoplankton were recorded during the present study period from both the stations which includes 50 species belongs to diatoms (Bacillariophyceae), 17 species of dinoflagellates (Dinophyceae) and only one Blue green (Cyanophyce). During the present study diatoms contribute maximum percentage (77.96% and 74.62%) followed by dinoflagellates (20.33% and 23.88%) and blue green algae registered their percentage to (1.69% and 1.49%) at station 1and 2 respectively. Maximum density (99,690 cell 1 and 1,378 cell 1 )and the minimum (76,150 cell 1 and 1, 097 cell 1 ) were recorded correspondingly 11 1 1 at station I and station 2. Species diversity varied from 3.988 to 5.398 during the study period. The minimum (3.988 and 5.215) and the maximum (5.121and 5.398) was recorded respectively at station 1 and 2. Phytoplankton Species richness ranged from 0.962 to 0.976. during the study period. The minimum (0.962 and 0.970) and the maximum (0.969 and 0.976) was recorded respectively at station 1 and station 2. Phytoplankton Species evenness varied from 0.968 to 0.983 during the study period. The minimum (0.968 and 0.968) ant the maximum (0.983 and 0.981) was recorded respectively at station 1 and station 2. Phytoplankton is microscopic single celled aquatic Phytoplankton can be used as bio indicators since plants forming the prime component in the food chain they reflect even the slight changes taking place in their of an aquatic ecosystem. The planktonic algae especially immediate environment by changing their species diatoms constitute the 'pastures of the sea'. The composition, biomass, community structure, chlorophyll fertility of sea is determined by its bio productivity. pigment content and productivity moreover and marine Phytoplankton production contributes about 95% of total ecosystem is largely determined by their phytoplankton production in the marine environment. The rate of gross population. primary productivity is important for assessing the fisheries yield. Hence the abundance of phytoplankton MATERIALS AND METHODS can be taken as the best means for quantitative assessment of potential fisheries of an area. Some Study Area: The station is relatively less polluted as there phytoplankton species are also often used as good are no river discharges and industrial wastes disposal. indicators of water quality including pollution (1). The domestic sewage alone is let out in to the sea and the Phytoplankton too has immense values as they play human excreta on the sea shore mixes with the sea water. a vital role as aquaculture feed since they form the primary Rameswaram is a part of the southward extension of food producer. The great fishing grounds of the seas are the Bay of Bengal as its meets the Indian Ocean (Fig. 1). found in where algae are found in abundance. As the It straddles across the two countries India and Srilanka. most sensitive organisms they serve as indicators of The Gulf of Mannar region from Rameswaram Island to water quality with their ability to detect even the subtle Tuticorin. The Indian part of Gulf of Mannar covers changes taking place in their ambient environment. approximately an area of 10,500 sq. kms lying between