Bhimtal, is the largest of all the lakes covering 72 ha. Lake Naukuchia tal is the deepest of all, with a maximum of 40.8 m. The lake region of Bhimtal, Naukuchiatal and Sattal is unique for its biodiversity since it falls in the blend zone of Paleastic and Indo-Malayan zoo-geography.

Three lakes (Nainital, Sattal and Naukuchiatal) in the Kumaun Himalayan region were investigated for total organic carbon and nitrogen, their atomic ratios and isotopic composition in their sediments. These geochemical proxies measured in 34-45 cm long cores indicate that organic matter preserved in the lake sediments is primarily derived from algal matter.

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