author(s)
Praveen Joshi HS, Ramachandra Naik AT, Narshivudu Daggula, Padmanabha A, Lingesh and Mohan Maloth

abstract
Primary production refers to estimation of the ability of an ecosystem to understand the level of Physico-chemical characteristics, Plankton production and primary productivity an attempt been done in the present study. The present study of Pilikula lake water sample physicochemical parameters were analyzed at fortnightly intervals over a period of 7 months from January to July 2017. This study revealed that the phytoplankton Abundance and Distribution, throughout the study period mainly observed that, a total of 38 species belonging to 4 genera were reported with a complete domination from Chlorophyta of 18 genus followed by Cyanophyta with 14 genus, Chrysophyta with 5 genus, and Rhodophyta with one genera. The total phytoplankton numbers varied from a minimum of 43 counts/l during February to a maximum of 5508 counts/l during May. In all, summer and monsoon months showed maximum number of Phytoplankton compared to winter months. The gross primary productivity of organic matter by the phytoplankton was found to be more during pre-monsoon and early monsoon period. A similar trend was also seen in net primary productivity and respiration rate values. During the study period, it has been noticed that net productivity was comparatively low, suggesting that major part of the organic matter produced by photosynthesis had been utilised for respiration. On the other hand, Community respiration was found to be higher during summer season and lower during winter season. However that the Pilikula lake primary production and productivity mainly depending on the biotic and abiotic factors like sunlight, organic carbon and concentration of available nutrients like Phosphorus and Nitrogen.