Lacustrine sediment preserves high-resolution biogeochemical records of past variations in water-shed processes controlling lake sedimentation.The current study explores historical variations in autochthonous and allochthonous sediment supplies to a large tropical freshwater lake system(Upper Lake,Bhopal)protected under the international Ramsar Convention of 2002 against anthropogenic pressures.For this purpose,multi-proxy biogeochemical data are presented for organic matter(total organic carbon,total nitrogen,phosphorous,and loss on ignition[LOI]at 550℃),carbonate(LOI at 950℃),lithic sediment(aluminum,titanium,iron,calcium,magnesium,sodium,potassium,manganese,zirconium,niobium,hafnium,tantalum,thorium,uranium,and rare earth elements),and anthropogenic inputs(lead)measured in a 38 cm long sediment core retrieved from the lake.In addition to the lacustrine sediment core,the samples of catchment bedrock,surface soils,major stream sediment,and eolian dust collected from the lake periphery also are analyzed.The systematic biogeochemical excursions in the upper core section(top～8 cm)indicate increased anthropogenic inputs,watershed denudation by agricultural activities,artificially reduced fluvial sediment supply,relatively increased dust inputs and lake eutrophication in the last few decades.The current study underscores the roles of anthropogenic land-use and wetland conservation practices in the rapid alteration of autochthonous and allochthonous sediment supplies to open aquatic eco-systems.Further,rising lake eutrophication levels despite a managed reduction in allochthonous sediment supplies seem challenging to control due to dissolved nutrient supply from urban sewage discharge and runoff from agricultural land in the watershed.

Department of Earth and Environmental Sciences,Indian Institute of Science Education and Research Bhopal,Bhopal 462066,Madhya Pradesh,India;Geosciences Division,Physical Research Laboratory,Ahmedabad 380009,Gujarat,India;Department of Earth and Climate Science,Indian Institute of Science Education and Research,Pune 411008,India

[1]Nafees Ahmad;Satinder Pal Singh;Aasif Mohmad Lone;Abul Qasim;Ravi Bhushan;Gyana Ranjan Tripathy;Chinmay Shah-.Historical variations in autochthonous and allochthonous sediment supplies to the largest freshwater lake in Central India)[J].国际泥沙研究（英文版）,2022(05):563-575

Bhopal,eolian

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