CCMB study reveals microbial diversity in Eastern Ghats lakes

A first-of-its-kind large-scale study of bacterial communities across lakes and reservoirs in the Eastern Ghats by scientists from LaCONES, CSIR–Centre for Cellular and Molecular Biology (CCMB) in Hyderabad, has revealed striking patterns of microbial diversity. Lakes inside protected areas showed significantly higher bacterial richness, while those near industrial zones exhibited reduced diversity.

The research provides a comprehensive microbial map of the Eastern Ghats, underscoring the pivotal role of bacteria in sustaining water quality, nutrient cycling, and ecosystem resilience, said LaCONES CSIR-CCMB chief scientist G. Umapathy on Monday (December 1, 2025).

The Eastern Ghats, a discontinuous mountain range along India’s eastern coast, is intersected by major rivers such as Krishna, Kaveri, Mahanadi, and Godavari. Climate change is a key driver of microbial shifts, altering biogeochemical cycles in aquatic systems, yet its impact on Eastern Ghats lakes remains poorly understood, he noted.

Unique bacterial signature in each lake

Using environmental DNA (eDNA) from 40 sites across 23 waterbodies in Telangana, Andhra Pradesh, Tamil Nadu, and Odisha, the team generated over a million DNA reads per sample to uncover hidden bacterial diversity. The study, published in Global Ecology and Conservation, found that each lake harboured a unique bacterial signature with minimal overlap, indicating strong spatial structuring.

Role of rare bacterial species

Smaller waterbodies (<25 sq. km) showed the highest mean bacterial richness compared to medium and large lakes. Rare bacterial species, though low in abundance, played critical roles in pollutant degradation and stress-response pathways. Salinity and turbidity emerged as key environmental drivers shaping microbial communities.

Picocyanobacterium Vulcanococcus, vital for nitrogen cycling, was widespread, with Chilika Lake showing the highest abundance, followed by Nagarjunasagar, Peddadevulpally Lake, and Srisailam Dam. Pakhal Lake recorded the most unique bacterial compositions, while Pulicat and Chilika Lakes shared 568 bacterial types.

Five of the eight most abundant genera belonged to Cyanobacteria, with Chilika Lake and Nagarjunasagar showing higher Cyanobacterial blooms, signalling eutrophication risks — overly enriched with nitrogen and phosphorous.

“These findings show the ecological heterogeneity of Eastern Ghats providing a crucial baseline for freshwater conservation and environmental monitoring in the region,” said Dr. Umapathy, adding that protection status, waterbody size, and physiochemical heterogeneity shape microbial communities. Co-authors include Manisha Ray, Neeldeep Ganguly, and Abhijeet Mondal.