Diatoms as Windows into the Past: Tracing Climate and Culture from Swamps to Settlements

Speaker: Dr. Mital Thacker

Abstract:‍Diatoms, microscopic algae with siliceous shells, are among the most sensitive and well- preserved environmental indicators in aquatic and terrestrial ecosystems. This lecture explores how diatoms serve as powerful proxies to reconstruct past climates, ecological dynamics, and human environment interactions across diverse South Asian contexts. Drawing from modern diatom assemblages in the rare Myristica swamp forests of the Western Ghats and sediment cores from the Holocene period, the talk showcases how diatom data reveal long-term environmental transitions. It then transitions into novel archaeological applications of diatoms, examining Iron Age pottery, paleochannels, and urban settlement stratigraphy – to infer past water use, settlement intensity, and cultural resilience. The lecture concludes with a look at upcoming research in the Banni Plains, where classical microscopy and sedimentary DNA (sedaDNA) will be combined to study biodiversity and reconstruct past climates in semi-arid landscapes. Together, these studies demonstrate the potential of microfossil proxies to illuminate both climatic and cultural narratives in tropical South Asia.