Plankton diversity in Pulicat

A total of 37 species of phytoplankton recorded during the present study in all twenty sampling points. Among them, 26 species were diatoms (Bacillariophyceae), 8 species were dinoflagellates (Dinophyceae), 2 species were blue greens (Cyanophycea) and 1 species were green algae. A total of 19 species of zooplankton recorded in all twenty sampling points under 7 major groups.The species, Chaetoceros compessus, Chaetoceros curvisetus, Coscinodiscus radiates, Coscinodiscus gigas, Nitzschia longissima, Planktoniella sol, Pleurosigma elongatum were occurred in twelve sampling points showed maximum spatial distribution and Navicula showed highest distribution in the Pulicat lake. The species of zooplankton, Favella sp, Acartia spinacuda, and Lucifer hanseni were noticed that they colonize and proliferate high numbers in Pulicat lake, where as the species, Globigerina sp, Sagitta elegans, Sagitta enflata, Pontella sp, macrosetella, microsetella, Oithona rigida were observed very meager in numbers. Station 1 and St. 2 were observed to have high proliferation of phytoplankton with the number of 13 and 12 species respectively. The density of phytoplankton varied from 1,01,910.828 to 5,94,479.8301 no/l in monsoon and 67940.55202 to 628450.1062 no/l in Postmonsoon season. The density of zooplankton varied from 3397.027 to 30573.248 (monsoon) and 679.4055 to 30573.248(Post monsoon) no/l. Among in different seasons, maximum species diversity (2.91) was observed in monsoon little lower in postomnsoon season of phytoplankton. Maximum species diversity (2.83) was observed in monsoon little lower in postomnsoon season of zooplankton.The study area is subjected to moderate fluctuations in temperature (29 – 32 in monsoon and 30.1 to 32.1in post monsoon ^oC). 20ppt is the minimum salinity in monsoon and maximum of 30ppt where as 31 is the minimum salinity in post monsoon and 34 is the maximum. Higher pH was recorded in St. 7 (monsoon), St. 1,15 16 (post monsoon)and lower pH noticed in St.12,14,17 (monsoon) and St.12 (post monsoon) of the Pulicat lagoon. Dissolved oxygen in the present study varied from 1.3 (St.5) to 5.6 mg/l (Fig.20) in monsoon and 2.4 (St. 13 and 15) to 3.5 (St.8) mg/l in Post monsoon. High content of nitrate in St 20 (both monsoon and post monsoon) and low value in St 6,7 (monsoon) St.3 (post monsoon) were observed in all stations. High amount of nitrite was recorded as 9.466 (monsoon) (St.13) 2.43 (post monsoon) (St. 20) µg/l and low as 0.106  and 0.095 µg/l (St.2) in both monsoon and post monsoon). Phosphate varied from 0.019 (St. 6) to 01.108 (St.20) µg/l in monsoon and post monsoon fluctuated between 0.03 (St.8) to 2.43 (St.17) µg/l. Silicate varied from 0.80 (St. 20) µg/l to 7.45 (St.6) µg/l in monsoon and varied from 0.02 (St. 1) µg/l to 4 (St.12) µg/l in post monsoon. Further details, Pl contact us.