Microeukaryote community coalescence strengthens community stability and elevates diversity

Area of Science:

• Microbiology
• Ecology
• Environmental Science

Background:

• Microbial community mixing is common but poorly understood.
• Estuarine environments involve interactions between freshwater and brackish water microbial communities.
• Microeukaryotes play crucial roles in aquatic ecosystems.

Purpose of the Study:

• To investigate the effects of mixing freshwater and brackish microbial communities on microeukaryotes.
• To assess the impact of environmental and community coalescence on microeukaryotic community structure and stability.
• To determine how mixing ratios and frequencies influence coalescence outcomes.

Main Methods:

• A microcosm experiment was conducted, mixing freshwater river and brackish sea microbial communities.
• Environmental conditions mimicking estuarine settings were established.
• Microeukaryotic community composition, diversity, and stability (community cohesion) were analyzed under varying mixing scenarios.

Main Results:

• Coalesced communities showed a shift towards the sea parent community composition, indicating asymmetrical outcomes.
• Community coalescence generally increased alpha diversity and stability, with increased negative cohesion.
• Diatoms were negatively affected, while fungi, ciliates, and cercozoans were promoted.
• Predictability of outcomes was higher when the sea community dominated and when mixing was repeated.

Conclusions:

• Community coalescence significantly alters microeukaryotic community structure and stability in estuarine environments.
• Mixing ratios and frequencies are critical factors influencing coalescence outcomes and predictability.
• Repeated mixing events enhance the predictability of community coalescence, with implications for understanding microbial community dynamics in changing environments.