Biodiversity in the occurrence of different species of phytoplankton along the Chennai coast
Authors: Palani Hemasankari , Prema D. , Kaladharan P. , Kripa Vasanth , Vinod K. , Kumar R. Narayana 
Published: January 2023

Phytoplankton is the major food of zooplankton and small pelagic occurring along the Chennai coast. The distribution of phytoplankton vary from place to place and the occurrence of different species decides the biodiversity of the ecosystem. This paper describes the occurrence and the characteristics of most common phyto organisms along the Chennai coast using primer 6.0 software. The phytoplankton distribution consists of dissolved volume, Ceratium species, Navicula, Bidulphia, Nitzschia, Gyrosigma and Chlorella during the year’2011. The occurrence of the phytoplankton, Chaetoceros, 38.01%, followed by Thalasirrothrix is 11.95%, Nitzschia is 8.94%, Navicula, 8.19%, Gyrosigma is 7.22%, Bidulphia is 6.57%, Coscinodiscus, 5.85%, Pleurosigma, 5.81%, Ceratium species, 4.58%, Chlorella is 2.74% and dissolved volume is 0.03% of the total phytoplankton distribution. The primer graphs for eclidean distance of different months for different species of phytoplankton were drawn. From the bray Curtis similarity graph it is evidenced that the distribution of phytoplankton component. Chaetocerus is far from the other species since its occurrence is more during the month of Jan’11. From the similarity graph, it is found that Chaetoceros and Coscinodiscus are closely related, Ceratium species and Pleurosigma are closely related, Navicula and Bidulphia are closely related. The occurrence of Chlorella is not closely related to any species. Bubble plots displays the individuals species abundances in relation to the overall community pattern. Funnel graphs are drawn for the number of phytoplankton. As the temperature increases during the summer month the phytoplankton decreases. The environmental variables, temperature, pH, salinity, TSS, TDS, dissolved oxygen, chlorophyll a, b and c, primary productivity, gross and net, nutrients, phosphate and ammonia vary significantly with the phytoplankton occurrence. The correlation coefficient of occurrence of Ceratium-Nitzschia (0.78), Ceratium- Thalassirothrix-(0.98), Ceratium- Pleurosigma (0.90), Navicula-Bidulphia (0.57), Navi cula-Nitzscia (0.10), Navicula -Gyrosigma (0.95), Navicula- Chaetoceros (0.93), Navicula- Coscinodiscus (0.57), Navicula-Pleurosigma (0.19), Bidulphia-Nitzschia (0.50), Bidulphia - Gyrosigma (0.31), Bidulphia- Chaetoceros (0.25), Bidulphia- Coscinodiscus (0.94), Nitzschia-Thalassirothrix (0.82), Nitzschia-Coscinodiscus (0.34), Nitzschia-Pleuro -sigma (0.64), Gyrosigma-Chaetoceros (0.99), Gyrosigma- Coscinodiscus (0.33), Gyro sigma-Pleurosigma (0.26), Chaetoceros-Coscinodiscus (0.26), Chaetoceros –Pleurosigma (0.30), Gyrosigma-Chlorella (0.09), Chaetoceros-Chlorella (0.05). The species richness, d varies from 0-2.40, Pielous’s index of evenness (J') varies from 0-0.97, Shannon–Wiener’s diversity index (H'), 0-2.32, simpson’s dominance index, , 0-0.9. The species richness, species evenness, species diversity and dominance index are all significant at p  0.05. The correlation between the environmental variables and the phytoplankton species distribution were worked out.