Bacterial metacommunity organization in a highly connected aquatic system.

Area of Science:

• Microbiology
• Ecology
• Limnology

Background:

• Bacterial communities in aquatic systems are widely studied, but mechanisms within large, connected lakes remain less understood.
• Previous research often focused on isolated water bodies, limiting insights into complex lake ecosystems.

Purpose of the Study:

• To investigate bacterial biofilm assembly mechanisms in a large, connected lake system in Northern Finland.
• To determine the roles of stochasticity, species sorting, and dispersal limitation in structuring bacterial communities.
• To assess the influence of abiotic and biotic factors on taxonomic and phylogenetic diversity.

Main Methods:

• Utilized associative methods analyzing taxonomic and phylogenetic alpha- and beta-diversity.
• Incorporated a comprehensive set of abiotic and biotic variables.
• Employed null model approaches to quantify community assembly processes.

Main Results:

• Spatial variation in bacterial communities was structured by stochasticity, species sorting, and dispersal limitation.
• Species sorting driven by abiotic conditions was a stronger driver of taxonomic and phylogenetic turnover than biotic variables.
• Abiotic factors and dispersal effects significantly influenced alpha diversity (species richness and phylogenetic diversity).

Conclusions:

• Bacterial biofilm biodiversity within lake ecosystems is primarily driven by within-habitat gradients in abiotic conditions.
• Stochastic and deterministic dispersal processes play crucial roles in bacterial community assembly.
• Understanding these assembly mechanisms is key for managing and conserving freshwater bacterial ecosystems.