Evidence for the existence and ecological relevance of fast-cycling mineral-associated organic matter
| Authors: | Andrea Jilling, A. Stuart Grandy, Amanda B. Daly, Rachel Hestrin, Angela Possinger, Rose Abramoff, Madison Annis, Anna M. Cates, Katherine Dynarski, Katerina Georgiou, Katherine A. A. Heckman, Marco Keiluweit, Ashley Lang, Richard P. Phillips, Katherine Rocci, Itamar A. Shabtai, Noah W. Sokol, Em D. Whalen |
| Year: | 2025 |
| Type: | Scientific Journal |
| Station: | Northern Research Station |
| DOI: | https://doi.org/10.1038/s43247-025-02681-8 |
| Source: | Communications Earth & Environment |
Abstract
Longstanding theories and models classify mineral-associated organic matter as the large ( ~ 60%) but slow-cycling and persistent portion of soil organic matter. Strong physico-chemical interactions and diffusion limitations restrict the turnover of mineral-associated organic matter, allowing carbon and nitrogen bound therein to persist in soil for as long as centuries to millennia. However, mineral associated organic matter is a chemically and functionally diverse pool with a substantial portion cycling at relatively fast (i.e., minutes to years) timescales. Despite a growing body of evidence for the heterogenous and multi-pool nature of mineral-associated organic matter, we lack consensus on how to conceptualize and directly quantify fast-cycling mineral-associated organic matter and its ecological significance. We demonstrate that the dynamic qualities of fast-cycling mineral-associated organic matter vary based on 1) the chemistry of the mineral particles and organic matter, 2) the complex set of interactions between organic matter and the mineral matrix, and 3) the presence and strength of destabilizing forces that lead to decomposition or loss of mineral-associated organic matter (i.e., plant-microbe interactions, agricultural intensification, and climate change). Finally, we discuss potential implications and research opportunities for how we measure, manage, and model the dynamic subfraction of this otherwise persistent pool of soil organic matter.