Response of diatoms to water quality in Khajiyar lake, Himachal Pradesh

Abstract

The present investigation was carried out to study the presence, abundance and distribution of diatoms in relation to the water quality of Khajiyar Lake, Himachal Pradesh during April, 2011 to January, 2012. The lake is about 2000 m above sea level and is situated at 32? 32? 53? N and 76? 3? 34?E. Surface water samples were collected from the Khajiyar lake for six months over the year in the month of April-May in summers, July-August during rainy season and December-January in winters. The diatoms presence, abundance and distribution were found to be greatly influenced by the physico-chemical regime of the lake. The diatoms density showed highly significant and positive relationship with conductivity (r = 0.869, p<0.01), and chloride (r= 0.857, p<0.01) and positive relationship with nitratenitrogen and total phosphate-phosphorus. The higher values of free carbon dioxide (11.0-26.8 mg/L), chloride (20.2-33.1mg/L), nitratenitrogen (0.098-0.485mg/L), total phosphate-phosphorus (0.62-2.32mg/L), very low percentage of oxygen indicators species and the presence and abundance of pollution indicator diatom species such as Diatoma vulgare (5%), Navicula gracilis (24%), Navicula gibba (8%), Pinnularia nobilis (12%), Nitizschia sigmoidea (3%), Gomphonema geminatum (23%), Frustulia rhomboides (2%), Tabellaria fenestrata (2%) and Cylinderotheca gracilis (4%) throughout the investigation indicated highly deteriorated water quality of the lake ecosystem. Study thus demonstrated response of diatoms to changing water quality and their role as bio-indicators.