Synthetic Denitrifying Communities Reveal a Positive and Dynamic Biodiversity-Ecosystem Functioning Relationship...

Area of Science:

• Microbial ecology
• Evolutionary biology

Background:

• Biodiversity-ecosystem functioning (BEF) relationships are well-studied in macro-organisms but remain elusive in microbial systems.
• Microbial communities offer a tractable model to investigate BEF dynamics due to their rapid growth and metabolic versatility.
• Understanding how BEF relationships evolve is crucial for predicting ecosystem stability and function.

Purpose of the Study:

• To investigate the existence and evolution of biodiversity-ecosystem functioning (BEF) relationships in microbial systems.
• To determine how community richness influences productivity and denitrification rates over evolutionary time.
• To elucidate the mechanisms driving BEF relationships in evolving microbial communities.

Main Methods:

• Construction of synthetic denitrifying communities (SDCs) with varying species richness (1-12 species) from 12 *Shewanella* denitrifiers.
• Experimental evolution of SDCs for approximately 180 days with continuous monitoring of community functions.
• Analysis of productivity (biomass) and denitrification rates, and assessment of biodiversity effects (complementarity).

Main Results:

• Initially, higher community richness correlated positively with productivity and denitrification rates.
• This positive correlation was transient, significant only in the early stages (0-60 days) of evolution.
• Community functions generally increased over 180 days, with lower-richness communities showing greater functional increases than higher-richness ones.
• Positive BEF relationships were primarily driven by complementary effects, more pronounced in lower-richness communities.

Conclusions:

• The biodiversity-ecosystem functioning (BEF) relationship in microbial systems is dynamic and evolves over time.
• Complementary effects play a significant role in driving BEF relationships, particularly in less diverse communities.
• Experimental evolution can alter BEF relationships, with lower-richness communities exhibiting greater functional adaptation.