Studies on phytoplankton characteristics in Ayyampattinam coast, India.

ABSTRACT

Physico-chemical variables in the marine environment are subjected to wide spatio-temporal variations. The various physico-chemical parameters viz temperature, salinity, pH, dissolved oxygen and nutrients of the environment are the factors which mainly influence the production and successful propagation of planktonic life in the coastal biotopes. The ranges of values of surface water temperature (0°C), salinity (‰), pH and dissolved oxygen (ml l-1) were 25.5 - 33.4; 23 - 35; 7.8 - 8.2; 3.6 - 5.2, respectively. The values (Cg l-1) of nutrients were nitrate 3.21 - 6.34, nitrite 0.74 - 0.896, phosphate 0.22 and 1.16, silicate 24.85 - 61.92 and ammonia 0.05 - 0.32. The recorded values of primary productivity (mgcm-3hr-1) ranged between 16 – 116 and the chlorophyll “a” varied from 3.74 – 8.52. A total number of 51 species of phytoplankton representing different classes viz Bacillariophyceae (40); Dinophyceae (8); Chlorophyceae (1) and Cyanophyceae (2) was recorded. Among the four classes, Bacillariophyceae appeared to be the dominant group in respect of total species and cell numbers. The population density of phytoplankton was high during summer season and quite low during monsoon season.