Persistence of soil organic carbon caused by functional complexity

• Published in: Nature geoscience Vol. 13; no. 8; pp. 529 - 534
• Main Authors: Lehmann, Johannes, Hansel, Colleen M., Kaiser, Christina, Kleber, Markus, Maher, Kate, Manzoni, Stefano, Nunan, Naoise, Reichstein, Markus, Schimel, Joshua P., Torn, Margaret S., Wieder, William R., Kögel-Knabner, Ingrid
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.08.2020; Nature Publishing Group
• Subjects: 704/106; 704/106/47/4113; 704/47; 704/47/4113; biogeochemistry; Carbon; Carbon capture and storage; carbon cycle; Carbon dioxide; Carbon dioxide atmospheric concentrations; Carbon sequestration; Climate change; Climate change mitigation; climate sciences; Complexity; Control stability; Decomposers; Decomposition; Drawdown; Dynamic stability; Earth and Environmental Science; Earth Sciences; Earth System Sciences; ENVIRONMENTAL SCIENCES; Geochemistry; Geology; Geophysics/Geodesy; Global Changes; Management; Microorganisms; Mitigation; Organic carbon; Organic matter; Organic soils; Perspective; Soil; Soil chemistry; Soil dynamics; Soil management; Soil stability; Soils; Temporal variations
• ISSN: 1752-0894; 1752-0908; 1752-0908
• DOI: 10.1038/s41561-020-0612-3

Soil organic carbon management has the potential to aid climate change mitigation through drawdown of atmospheric carbon dioxide. To be effective, such management must account for processes influencing carbon storage and re-emission at different space and time scales. Achieving this requires a conceptual advance in our understanding to link carbon dynamics from the scales at which processes occur to the scales at which decisions are made. Here, we propose that soil carbon persistence can be understood through the lens of decomposers as a result of functional complexity derived from the interplay between spatial and temporal variation of molecular diversity and composition. For example, co-location alone can determine whether a molecule is decomposed, with rapid changes in moisture leading to transport of organic matter and constraining the fitness of the microbial community, while greater molecular diversity may increase the metabolic demand of, and thus potentially limit, decomposition. This conceptual shift accounts for emergent behaviour of the microbial community and would enable soil carbon changes to be predicted without invoking recalcitrant carbon forms that have not been observed experimentally. Functional complexity as a driver of soil carbon persistence suggests soil management should be based on constant care rather than one-time action to lock away carbon in soils. Dynamic interactions between chemical and biological controls govern the stability of soil organic carbon and drive complex, emergent patterns in soil carbon persistence.