Community and single cell analyses reveal complex predatory interactions between bacteria in high diversity systems

Area of Science:

• Community ecology
• Microbial ecology
• Predator-prey dynamics

Background:

• Investigating predator-prey interactions in complex environments is challenging.
• Microbial microcosms are useful but do not fully represent natural systems.

Purpose of the Study:

• To determine the role of Bdellovibrio and like organisms (BALOs) in regulating prey populations within wastewater treatment plants.
• To understand how these interactions influence food-web stability and species coexistence in complex microbial communities.

Main Methods:

• A 1-year survey of wastewater treatment plant microbial communities.
• Sequence-based analysis to identify predator and prey populations.
• Single-cell sorting combined with fluorescent hybridization and community sequencing for validation.

Main Results:

• BALOs were found to regulate prey populations, potentially in a density-dependent manner.
• Both abundant and rare prey populations were affected by predation.
• Predatory interactions created an oscillating landscape, maintaining overall population stability.
• Niche partitioning, driven by differential prey ranges, explained the coexistence of numerous predator species.

Conclusions:

• Predator-prey interactions, specifically by BALOs, are crucial for maintaining stability and promoting species coexistence in complex microbial ecosystems like wastewater treatment plants.
• The study validates sequence-based findings with experimental methods, offering a robust approach for future ecological studies.