Phytoplankton ecology of the cochin backwaters

46-50Average concentration of phytoplankton in the Cochin backwaters varied from 22200 to 299700 cells/litre. The minimum and maximum numbers were observed during September and November. Diatoms, dinoflagellates and other algae had their maximum concentration during postmonsoon, premonsoon periods respectively. On few occasions diatoms and dinoflagellates were found to bloom. The maximum concentration observed during a bloom was 2 million cells/litre. A negative correlation was found between cell concentration and salinity. Variation of phytoplankton was directly related to that of phosphate and nitrite. Cell numbers and organic carbon production showed a positive relation. Species diversity index varied from 1.59 to 4.50 and the lowest was observed during a phytoplankton bloom