| Autor: |
Davenport R; Soil and Crop Sciences, School of Integrative Plant Sciences, Cornell University, Ithaca, NY 14850., Bowen BP; Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720.; Metabolomics Technology Group Joint Genome Institute, Department of Energy, Walnut Creek, CA 94598., Lynch LM; Soil and Crop Sciences, School of Integrative Plant Sciences, Cornell University, Ithaca, NY 14850., Kosina SM; Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720., Shabtai I; Soil and Crop Sciences, School of Integrative Plant Sciences, Cornell University, Ithaca, NY 14850., Northen TR; Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720.; Metabolomics Technology Group Joint Genome Institute, Department of Energy, Walnut Creek, CA 94598., Lehmann J; Soil and Crop Sciences, School of Integrative Plant Sciences, Cornell University, Ithaca, NY 14850.; Department of Global Development, Cornell University, Ithaca, NY 14850.; Cornell Institute for Digital Agriculture, Cornell University, Ithaca, NY 14850.; Cornell Atkinson Center for Sustainability, Cornell University, Ithaca, NY 14850. |
| Abstrakt: |
Soil organic matter (SOM) is comprised of a diverse array of reactive carbon molecules, including hydrophilic and hydrophobic compounds, that impact rates of SOM formation and persistence. Despite clear importance to ecosystem science, little is known about broad-scale controls on SOM diversity and variability in soil. Here, we show that microbial decomposition drives significant variability in the molecular richness and diversity of SOM between soil horizons and across a continental-scale gradient in climate and ecosystem type (arid shrubs, coniferous, deciduous, and mixed forests, grasslands, and tundra sedges). The molecular dissimilarity of SOM was strongly influenced by ecosystem type (hydrophilic compounds: 17%, P < 0.001; hydrophobic compounds: 10% P < 0.001) and soil horizon (hydrophilic compounds: 17%, P < 0.001; hydrophobic compounds: 21%, P < 0.001), as assessed using metabolomic analysis of hydrophilic and hydrophobic metabolites. While the proportion of shared molecular features was significantly higher in the litter layer than subsoil C horizons across ecosystems (12 times and 4 times higher for hydrophilic and hydrophobic compounds, respectively), the proportion of site-specific molecular features nearly doubled from the litter layer to the subsoil horizon, suggesting greater differentiation of compounds after microbial decomposition within each ecosystem. Together, these results suggest that microbial decomposition of plant litter leads to a decrease in SOM α-molecular diversity, yet an increase in β-molecular diversity across ecosystems. The degree of microbial degradation, determined by the position in the soil profile, exerts a greater control on SOM molecular diversity than environmental factors, such as soil texture, moisture, and ecosystem type. |
