Microbial Communities Influence Soil Dissolved Organic Carbon Concentration by Altering Metabolite Composition

Abstract

Rapid microbial growth in the early phase of plant litter decomposition is viewed as an important component of soil organic matter (SOM) formation. However, the microbial taxa and chemical substrates that correlate with carbon storage are not well resolved. The complexity of microbial communities and diverse substrate chemistries that occur in natural soils make it difficult to identify links between community membership and decomposition processes in the soil environment. To identify potential relationships between microbes, soil organic matter, and their impact on carbon storage, we used sand microcosms to control for external environmental factors such as changes in temperature and moisture as well as the variability in available carbon that exist in soil cores. Using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) on microcosm samples from early phase litter decomposition, we found that protein- and tannin-like compounds exhibited the strongest correlation to dissolved organic carbon (DOC) concentration. Proteins correlated positively with DOC concentration, while tannins correlated negatively with DOC. Through random forest, neural network, and indicator species analyses, we identified 42 bacterial and 9 fungal taxa associated with DOC concentration. The majority of bacterial taxa (26 out of 42 taxa) belonged to the phylum Proteobacteria while all fungal taxa belonged to the phylum Ascomycota. Additionally, we identified significant connections between microorganisms and protein-like compounds and found that most taxa (12/14) correlated negatively with proteins indicating that microbial consumption of proteins is likely a significant driver of DOC concentration. This research links DOC concentration with microbial production and/or decomposition of specific metabolites to improve our understanding of microbial metabolism and carbon persistence.

Simulated nitrogen deposition and precipitation events alter microbial carbon cycling during early stages of litter decomposition

“…More recently microbial community composition was found to create signi cant variation in carbon ow measured as DOC and respiration (CO 2 ) across litter types of varying substrate quality during short-term litter decomposition (Kroeger et al 2021). These ndings add to a growing body of literature (Albright et al 2020b(Albright et al , a, 2022Campbell et al 2022) that highlight the important in uence of microbial community composition on carbon ow from litter decomposition. In these previous studies, large microbiome effects were quanti ed unambiguously by holding environmental conditions constant, isolating the litter microbiome as the single factor driving variation in carbon ow.…”

Nutrient fluxes via litterfall in silver birch (Betula pendula Roth) stands growing on post-arable soils

“…Susceptible components (i.e., proteins, amino acids, monosaccharides, etc.) are a labile, easily degradable fraction of the SOM, playing an important ecological role as a source of energy for the soil microbiota (Campbell et al 2022). Additionally, molecular characteristics strongly in uence the microbial biomass, its community structure, and functions (Wu et al 2018;Zhalnina et al 2018).…”

Nutrient fluxes via litterfall in silver birch (Betula pendula Roth) stands growing on post-arable soils

“…proteins, amino acids, monosaccharides, etc.) are a labile, easily degradable fraction of the SOM, playing an important ecological role as a source of energy for the soil microbiota (Campbell et al 2022). Additionally, molecular characteristics strongly influence the microbial biomass, its community structure, and functions (Wu et al 2018;Zhalnina et al 2018).…”

“…This widely distributed tree has adapted to function in a wide spectrum of climatic (Titmuss 1959; Communicated by Agustin Merino. Browicz 1979) and site (Bown 1995) conditions. Additionally, its rapid growth, early fertility, and seed dispersal by wind explain its high succession potential (Úradníček et al 2009;Špulák et al 2010;Oikonomakis and Ganatsas 2020).…”