Microbial community dynamics and its relationship with biogeochemical processes under geochemical perturbations

Area of Science:

• Environmental Microbiology
• Biogeochemistry
• Ecosystem Science

Background:

• Environmental microbial communities are vital for ecosystem functions.
• Human-induced geochemical changes increasingly affect these communities.
• The link between microbial shifts and biogeochemical processes under stress is unclear.

Purpose of the Study:

• To investigate microbial taxonomic and functional dynamics under elevated nitrate conditions.
• To quantitatively connect microbial community structure to geochemical reaction kinetics using a novel model.
• To understand how geochemical perturbations influence microbial function and ecosystem processes.

Main Methods:

• Time-series sediment incubation experiments.
• 16S rRNA gene sequencing, quantitative PCR (qPCR), and metagenomics.
• Development of a gene-centric, process-based biogeochemical model.

Main Results:

• Functional metagenomics offered a broader view of microbial functional diversity than qPCR.
• A quantitative coupling between functional gene abundance and reaction rates was identified under geochemical perturbations.
• Abiotic processes and reaction nonlinearities can obscure the microbial-ecosystem linkage.

Conclusions:

• Gene-centric, process-based models are valuable for predicting ecosystem behavior under geochemical stress.
• This study improves understanding of the microbial function-biogeochemical process linkage.
• Standard statistical approaches may struggle to resolve complex interactions in perturbed ecosystems.