Revealing Cryptic Changes of Cyanobacterial Community Structure in Two Eutrophic Lakes Using eDNA Sequencing

Area of Science:

• Environmental microbiology
• Aquatic ecology
• Eutrophication studies

Background:

• Harmful cyanobacterial blooms (HCBs) are a global threat to human health and aquatic ecosystems.
• Understanding the drivers of cyanobacterial bloom formation is crucial for effective management.

Purpose of the Study:

• To investigate the spatiotemporal dynamics of cyanobacterial diversity and community composition in two Chinese eutrophic lakes.
• To identify key factors influencing cyanobacterial community structure and bloom formation potential.

Main Methods:

• High-throughput sequencing of the cpcBA-IGS gene from environmental DNA (eDNA) collected over two years.
• Analysis of operational taxonomic units (OTUs) to determine cyanobacterial diversity and abundance.
• Application of the Sloan neutral model and correlation analysis to assess ecological processes.

Main Results:

• Microcystis was the dominant genus in both Erhai Lake and Lushui Reservoir, but Erhai Lake exhibited higher cyanobacterial diversity.
• Opportunistic species like Phormidium and Synechococcus showed potential for dominance.
• Deterministic processes, particularly phosphorus availability, significantly influenced cyanobacterial community structure in Erhai Lake.

Conclusions:

• Eutrophic lake cyanobacterial communities are primarily shaped by deterministic processes, with Microcystis as a common dominant.
• Opportunistic species pose a risk for future bloom formation, highlighting the need for targeted monitoring for drinking water safety.