From carbon to phosphorus: Advancing compound-specific stable isotope analysis to decode soil organic matter dynamics across diverse environmental contexts

Soil organic matter (SOM) is a cornerstone of ecosystem stability, yet its response to anthropogenic pressure is governed by molecular-scale processes that bulk analyses often fail to capture. This award lecture will illustrate how the application of stable isotopes at the compound-specific level provides a high-resolution lens to elucidate SOM complexity and dynamics across diverse environmental frontiers. By transitioning from established carbon-cycle isotope research to the pioneering frontier of organic phosphorus (OP) research, this work explores the molecular "fingerprints" of SOM dynamics.

In this award lecture, I will summarize my research on the molecular mechanisms of SOM transformation and the development of isotopic tools to decipher the turnover and fate of organic pools under varying environmental factors. First, I will provide an overview of how compound-specific stable isotope analysis (CSIA) revelas molecular shifts that precede detectable losses in diverse soil organic carbon forms, providing a diagnostic for soil vulnerability under diverse land uses and climate factors. This will comprise both a conventional biomarker extraction approach and a novel direct pyrolysis analytic technique.

Next, I will demonstrate how these isotopic approaches can be applied to disturbance ecology, specifically focusing on the resilience and transformation of organic matter in fire-affected soils. Finally, I will review the transition to the OP cycle, presenting innovative methodologies implemented to advance our understanding of C and P biogeochemical cycles, and providing unprecedented insights into the biogeochemical persistence of this major OP pool.

I will conclude by discussing how these molecular insights are vital for developing site-specific management strategies and interdisciplinary models that account for the simultaneous impacts of global change on multiple soil functions.