Saima Akhter^1,, Onkar Singh Brraich²

Wetlands are considered as important ecosystems on this earth because they provide refuge and food to variety of aquatic biodiversity. Spatial heterogeneity of the phytoplankton community and seasonal diversity has been observed. Sampling of phytoplankton was carried out from the Ropar wetland, of Punjab, India between October 2015 to September 2017 at four representative sites (S1, S2, S3 and S4). Correlation of physico-chemical variables with phytoplankton density was recorded by using Pearson Correlation analysis and seasonal variation as well as a high influence of these physico-chemical parameters was observed on phytoplankton productivity. It has been observed that when temperature and amount of nutrients were higher, the density of phytoplankton was higher. The phytoplankton diversity showed higher sensitivity in the water, the dissolved oxygen and free CO2 showed significant negative correlation with all the physio-chemical parameters at all the sites. A total of 28 phytoplankton genera belonging to Bacillariophyceae (14 genera) Chlorophyceae (9 genera), Cyanophyceae (4 genera) and Dinophyceae (1 genus) were recorded from four sampling sites. Bacillariophyceae dominated both in diversity and percentage composition while Dinophyceae had shown least expression. Phytoplankton population showed high diversity in the summer and low in monsoon period. Various diversity indices (Shannon-Wiener diversity index, Simpson’s diversity index and Pielou evenness index) were used to found the seasonal variation of phytoplankton. The Shannon- Wiener diversity index was most useful in indicating the trophic status of the water as well as the pollution status, which in this case, depicted a moderate level of pollution in this wetland.

wetland, correlation coefficient, diversity indices, phytoplankton, seasonal variation