Distribution of Sedimentary Diatoms of Ooty Lake, Nilgiris District, Tamil Nadu, India: Implication on Water Quality Assessment using the Principal Component Analysis (PCA).

Diatoms occur in all natural conditions in lake and their distribution is mainly governed by the physicochemical composition of the water. Monitoring of water quality with physicochemical parameters is insufficient. Organic indicators of water quality monitoring used during the recent years have served as excellent tools in the areas of water pollution studies. Among all the fresh water organisms, diatoms are the most commonly used indicators of the water quality changes and paleoenvironments. In the present study, a total of 23 species distributed among 13 genera were recorded from the surface (grab) sediments of the Ooty Lake. Among these, the most abundant are Ulneria ulna, Cyclotella meneghiniana, Hantzschia amphioxys, Gomphonema affine, Aulacoseira granulata, Tabularia tabulata and Gomphonema gracile. Sediment samples were analysed for the organic matter, CaCO3, sand, silt and clay content, while water samples for pH, temperature and dissolved oxygen. The present finding mainly deals with the comparative study of diatom assemblages in relation to spatial-temporal changes in the environmental conditions of the Ooty Lake. The utility of the Principal Component Analysis (PCA) relative to diatoms to study the water quality of the Ooty Lake have also beendiscussed in the present work. [ABSTRACT FROM AUTHOR]