Abstract
Microbially-derived carbon inputs to soils play an important role in forming soil organic matter (SOM), but detailed knowledge of basic mechanisms of carbon (C) cycling, such as stabilization of organic C compounds originating from rhizodeposition, is scarce. This study aimed to investigate the stability of rhizosphere-produced carbon components in a model laboratory mesocosm of Pinus resinosa grown in a designed mineral soil mix with limited nutrients. We utilized a suite of advanced imaging and molecular techniques to obtain a molecular-level identification of newly-formed SOM compounds, and considered implications regarding their degree of long-term persistence. The microbes in this controlled, nutrient-limited system, without pre-existing organic matter, produced extracellular polymeric substances that formed associations with nutrient-bearing minerals and contributed to the microbial mineral weathering process. Electron microscopy revealed unique ultrastructural residual signatures of biogenic C compounds, and the increased presence of an amorphous organic phase associated with the mineral phase was evidenced by X-ray diffraction. These findings provide insight into the formation of SOM products in ecosystems, and show that the plant-and microbially-derived material associated with mineral matrices may be important components in current soil carbon models.
Original language | English (US) |
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Article number | 4 |
Journal | Soil Systems |
Volume | 1 |
Issue number | 1 |
DOIs | |
State | Published - Dec 2017 |
Externally published | Yes |
Keywords
- 16S sequencing
- Carbon cycle
- Electron microscopy
- Fourier-transform ion cyclotron resonance mass spectrometry
- Mineral weathering
- Mineral-organic associations
- Rhizosphere
- Soil microbiome
- Soil organic matter
ASJC Scopus subject areas
- Soil Science
- Earth-Surface Processes