Hyderabad: In a significant breakthrough for aquatic ecology and environmental monitoring, researchers from the CSIR-Centre for Cellular and Molecular Biology (CSIR-CCMB) have discovered that cyanobacterial communities in Chilika Lagoon undergo seasonal genetic changes. The findings could play a crucial role in predicting harmful algal blooms and improving conservation strategies in fragile water ecosystems.
The study, published in the scientific journal Environmental Advances was led by Manisha Ray and Govindhaswamy Umapathy. It provides new insights into how environmental factors, particularly salinity, influence the structure and function of cyanobacterial populations.
Researchers reconstructed 83 cyanobacterial metagenome-assembled genomes (MAGs) using environmental DNA collected from water samples across different seasons. Their analysis revealed that salinity is the dominant factor shaping not only the composition of cyanobacterial communities but also their biological functions, including nitrogen cycling, carbon fixation and toxin production.
The study highlights a concerning link between nutrient imbalance and the risk of harmful algal blooms. Specifically, low nitrogen-to-phosphorus ratios were found to create conditions that favour toxin-producing cyanobacteria. Such blooms can severely impact aquatic biodiversity and pose risks to human health by contaminating water supplies.
In a particularly notable discovery, scientists identified five cyanobacterial genomes containing a previously undocumented complete metabolic pathway known as the phosphate acetyltransferase–acetate kinase (Pta-Ack) pathway. This suggests a potentially unknown role in carbon fixation, opening new avenues for research into microbial contributions to global carbon cycles.
The research was a collaborative effort involving institutions such as LaCONES and the Academy of Scientific and Innovative Research (AcSIR), Ghaziabad. Together, the teams conducted extensive fieldwork and laboratory analysis to map microbial diversity in the lagoon.
Cyanobacteria are essential components of aquatic ecosystems. They perform photosynthesis, fix atmospheric nitrogen, contribute to carbon sequestration and support symbiotic relationships with other organisms. However, under certain environmental conditions, their rapid growth can lead to harmful algal blooms, disrupting ecosystems and threatening water quality.
The study was carried out in Chilika Lagoon, a unique and biodiverse ecosystem connected to the Bay of Bengal. Despite its ecological importance, the lagoon remains relatively understudied, making these findings particularly valuable.
To conduct the research, scientists collected water samples from nine different locations during four expeditions spanning three seasons. In total, 48 samples were analysed, including multiple replicates to ensure accuracy. At each site, at least 10 litres of water were filtered through fine membranes to capture microbial DNA. The extracted genetic material was then sequenced using advanced genomic technology and analysed through a series of computational processes, including trimming, filtering and taxonomic classification.
The results clearly demonstrated that salinity plays a critical role in determining both the diversity and functional capabilities of cyanobacterial communities in the lagoon. These seasonal genetic shifts influence how these microorganisms interact with their environment and contribute to nutrient cycles.
Researchers believe that understanding these patterns could significantly improve early warning systems for harmful algal blooms. This is particularly important in the context of climate change, which is expected to alter rainfall patterns, salinity levels and nutrient flows in coastal ecosystems.
By linking microbial genetics with environmental conditions, the study offers a powerful tool for managing water quality and protecting biodiversity. It also underscores the importance of monitoring invisible microbial changes that can have far-reaching impacts on ecosystems and human health.
As climate variability continues to stress aquatic environments, such research provides a scientific foundation for more informed conservation planning and sustainable management of vital water bodies like Chilika Lagoon.