Global assessment of CSSI land use fingerprints of long-chain fatty acids in soils

The 2025 "State of Food and Agriculture" (SOFA) report published by the Food and Agriculture Organization of the United Nations (FAO) reiterates the significant threat posed by soil erosion and land degradation to agricultural productivity, food security, and the resilience of ecosystems. The FAO estimates that around 1.7 billion individuals globally reside in regions facing yield gaps associated with human-induced land degradation (FAO, 2025).Numerous scientists across the globe, including our research team in Basel, have utilized and assessed d13C compound-specific stable isotopes (CSSI) derived from long-chain fatty acids across various land uses as tracers. This methodology has been employed to monitor and identify erosion stemming from different land uses to river or lake sediments (Alewell et al., 2016; Upadhayay et al., 2022), as well as to depositional sites (Mabit et al., 2018), and to investigate land use changes within soil chronosequences (Swales and Gibbs, 2020). This analytical tool can act as a significant asset for global decision-makers, aiding in the protection of soil and water resources both in a general context and in relation to specific United Nations Sustainable Development Goals (SDGs): 2 – Zero Hunger, 6 – Clean Water and Sanitation, 12 – Responsible Consumption and Production, 13 – Climate Action, 14 – Life Below Water, and 15 – Life On Land.We present data of isotopes collected over several years from different land use in various regions including Europe (Switzerland, France, England, Scotland), South Korea, and Brazil. The isotopic values transition from being more depleted in temperate Europe to more enriched in the semi-humid Brazilian savannah, with South Korea exhibiting intermediate values. Furthermore, additional data from over 40 internationally published studies have been compiled to enhance our findings.This is the first presentation of such a data collection, which can be continuously updated with the latest research findings, functioning as both an archive and a foundational data resource for sediment source attribution to ascertain the origins and potential causes of soil erosion. Additionally, a CSSI land use database encompassing numerous regions globally could significantly lessen the burden of costly and labor-intensive source soil sampling, particularly when time and resources are constrained. References:Alewell, C., Birkholz, A., Meusburger, K., Schindler Wildhaber, Y., and Mabit, L.: Quantitative sediment source attribution with compound-specific isotope analysis in a C3 plant-dominated catchment (central Switzerland), Biogeosciences, 13, 1587–1596, https://doi.org/10.5194/bg-13-1587-2016, 2016.FAO. 2025. The State of Food and Agriculture 2025 – Addressing land degradation across landholding scales. Rome.Mabit, L., Gibbs, M., Mbaye, M., Meusburger, K., Toloza, A., Resch, C., Klik, A., Swales, A., Alewell, C.,: Novel application of Compound Specific Stable Isotope (CSSI) techniques to investigate on-site sediment origins across arable fields, Geoderma, Volume 316, 2018.Swales, A. & Gibbs, M.: Transition in the isotopic signatures of fatty-acid soil biomarkers under changing land use: Insights from a multi-decadal chronosequence, Science of The Total Environment, Volume 722, 2020.Upadhayay, H.R., Granger, S.J. & Collins, A.L. Comparison of sediment biomarker signatures generated using time-integrated and discrete suspended sediment samples.Environ Sci Pollut Res 31, 22431–22440 (2024).