author(s)
Kusumlata Goswami, M Das Trakroo, Sumit Kumar and Ashutosh Mishra

abstract
The present study was carried out to assess the occurrence and diversity of phytoplankton in relation to abiotic factors of Lake Nainital situated at Kumaon Himalayas of Uttarakhand State, India. The samples of phytoplankton and water were collected from three selected study sites S₁, S₂ and S₃ for a period of eight months from September, 2016 to April, 2017. The phytoplankton composition of Lake Nainital consisted of four groups namely Bacillariophyceae (20 genera), Chlorophyceae (16 genera), Cyanophyceae (3 genera) and Euglenophyceae (2 genera). Dominant phytoplankton species of Lake were Fragilaria sp., Tabellaria sp., Gomphonema sp., Navicula sp., Amphora sp., Synedra sp. and Caloneis sp. The density of phytoplankton shows peak in the months of January and April, dominated by green algae and diatoms.