Inferring the Contribution of Microbial Taxa and Organic Matter Molecular Formulas to Ecological Assembly

Area of Science:

• Ecology
• Microbial Ecology
• Biogeochemistry

Background:

• Ecological community assembly is a fundamental ecological process.
• Understanding the drivers of community assembly, particularly the role of individual members, is crucial.
• Previous methods primarily focused on community-level assembly patterns, with less emphasis on individual feature contributions.

Purpose of the Study:

• To develop and validate a novel metric, feature-level βNTI (βNTI_feat), for assessing individual ecological feature impacts on community assembly.
• To investigate the contributions of specific microbial taxa and organic matter molecular formulas to ecological divergence and convergence.
• To explore potential coordination in assembly processes between microbial communities and organic matter pools.

Main Methods:

• Adaptation of the null model β-nearest taxon index (βNTI) to create feature-level βNTI (βNTI_feat).
• Application of βNTI_feat to microbial metacommunities and organic matter (OM) assemblages.
• Network analysis to relate βNTI_feat values between microbial and OM assemblages.

Main Results:

• Unclassified microbial lineages predominantly contributed to community divergence, while diverse groups like Crenarchaeota and Alphaproteobacteria drove convergence.
• In organic matter pools, CHO-containing formulas generally promoted convergence, whereas nitrogen- and phosphorus-containing formulas influenced both convergence and divergence.
• Network analysis indicated that N-containing formulas often coordinated with microbial assembly, and P-containing formulas acted more independently. Family Geobacteraceae showed coordinated assembly roles with N- and P-containing formulas.

Conclusions:

• Feature-level βNTI (βNTI_feat) is a powerful tool for dissecting the roles of individual components in ecological assembly.
• Specific microbial taxa and molecular formulas have distinct impacts on ecological divergence and convergence.
• Coordinated assembly processes exist between microbial communities and their abiotic environment, particularly concerning nutrient cycling.