Soil and Particle-Associated Microbial Communities

Soil organic matter, the largest terrestrial reservoir of organic carbon, plays a critical role in carbon cycling. Particulate organic matter provides a surface for microbial attachment and a resource for decomposition. Degradation of the two most abundant biopolymers in soil, cellulose and chitin requires an array of microbe-produced extracellular enzymes. Despite their importance for carbon cycling, the structure and temporal dynamics of particle-associated microbial communities remain poorly understood, particularly regarding how specific substrates influence community composition. This study aimed to determine whether microbial communities associated with particulate organic matter change in composition and richness over time and if chitin and cellulose select for distinct microbial taxa. Using custom mm-sized model particles designed to mimic particulate organic matter and containing chitin or cellulose, we incubated these particles in soil in the laboratory and in the field. Over seven weeks, we assessed bacterial, archaeal, and fungal communities at distinct time points, uncovering substrate-specific differences in community structure and temporal dynamics. Sequencing was performed at the Joint Microbiome Facility of the Medical University of Vienna and the University of Vienna under the project ID JMF-2106-12.