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In recent years, diatom studies have been consisting of different approach i.e., taxonomic study, contamination history, paleoclimate etc. The significant study has been reported from the different part of the Indian Especially in India, from the last several decades the study on diatom shifted from taxonomical classification to palaeothermometry study using isotopic analysis. To know the present status and get the future direction it is very important to review the past studies which not only gives the ample information about the records available but also benefitting to get future direction. In the present review we present the comprehensive review on records available from three different geopolitical regions. The review on these three regions shows that most of the work Indian parts in past decades diatom is mostly used for taxonomical and pollution study. diatom diversity has not been examined in many Indian regions. direction towards palaeothermometry reconstruction using advance analytical techniques such as stable isotope and others. [ABSTRACT FROM AUTHOR]

The lakes of the Himalaya are degrading due to increase in toxic heavy metal loading. This study reports the last 50-year heavy metal pollution loading in the Rewalsar Lake, Himachal Pradesh, India. Sediment cores were recovered to study the pollution loading in the lake sediments. The Cs and Pb isotope-based sedimentation rate suggest rapid sedimentation in the lake during the last ~50 years. The concentrations of Mn, Cu, Zn, Cd, Pb, Co, Ni, Cr metals in the lake sediments owe its contributions both to the natural and anthropogenic sources. Prior to ca 1990 AD, metal loading was dominated by the lithogenic input, whereas post ca 1990 AD the metal loading was controlled by the anthropogenic factors. The Pb concentration in the lake gradually increased during 1990-2004 and then decreased significantly till present. The higher concentration of Pb seems to be derived from the fossil fuel burning, while the Cr concentration in the lake indicates the use of fertilizer in the catchment area. The lowest concentrations of elements around ca 1990 AD seem to have occurred due to channelization of the lake feeding system. [ABSTRACT FROM AUTHOR]