Kolleru lake, the largest freshwater lake in India was studied for the assessment of dissolved organic matter distribution and the influence on the lake hydro chemical characteristics. The study revealed the significant influence of freshwater inputs and their control in the distribution of dissolved organic matter (DOM) throughout the lake. Correlation analysis indicated that the DOM mineralization decreased the DO concentration during the monsoon and post-monsoon, making the lake under saturated (upto 7% DO saturation) whereas, during pre-monsoon DO in the lake was not controlled by DOM. Mixing plots of DOC, DON and DOP versus salinity suggested that DON and DOP acted as sink during all the seasons, whereas DOC acted as a source due to domination of production over mineralization. This is the baseline information regarding the dissolved organic matter and will be useful for further intensive study on biogeochemistry of the lake
