Distribution of sediments and organic matter source: Berijam Lake, Tamil Nadu

Berijam lake, Tamil Nadu, situated at an elevation of 2165 m above mean sea level is a fresh water, irregular linear basin with two major linear arms located in the Palani hills. Lake floor sediments were collected covering the entire aerial extent of this lake basin to understand the sediment pattern distribution and plausible source of organic carbon. Textural pattern, CaCO 3 , Organic matter, TOC, TN content and the C/N ratio of the lake floor sediment samples were analysed and the data generated exhibit a distinct pattern of sediment distribution and deposition. Grain size data indicate that the clay is associated with both sand and silt and the lake is dominantly composed of sandy clay and silty clay. CaCO 3 content is low (2.70 to 0.80%) as there is no major source for CaCO 3 . OM, TOC and TN show positive correlation with silt. C/N ratio varies from (12.2 to 9.6) indicating dominantly algal organic matter. NNW, NNE and SSE region of the lake seems to have supported thick water column as high organic carbon, silt and clay content occur in these directions. C/N ratio indicates that the major source of organic matter is from the lake algae, aquatic weeds and plants.