Accelerator Mass Spectrometry Applications in Environmental Carbon Cycling

Accelerator Mass Spectrometry (AMS) has emerged as a transformative tool for tracing rare isotopes in environmental samples, notably radiocarbon (14C). By counting individual 14C atoms with parts-per-quadrillion sensitivity, AMS enables reconstruction of carbon dynamics across atmospheres, oceans, soils and biota on timescales from annual cycles to millennia. This technique underpins quantification of natural and fossil-fuel CO2 fluxes, elucidating the partitioning of anthropogenic emissions between land and ocean reservoirs, the timing and magnitude of ecological respiration and photosynthesis, and the turnover of organic carbon in diverse climates. High-resolution AMS studies—ranging from tree-ring chronologies that resolve the mid-20th-century bomb peak to sediment cores that archive long-term sequestration—have refined our understanding of global carbon budgets, informed Earth system models, and provided robust benchmarks for defining the onset of the Anthropocene epoch. Practical applications now extend to validation of emission inventories, verification of carbon-offset schemes and assessment of carbon-climate feedbacks vital for policy and mitigation strategies.

Research from Nature Portfolio

Studies exploiting precise AMS 14C measurements in tree rings have identified a synchronous global marker for the Anthropocene. Analysis of Southern Hemisphere wood archives captures the thermonuclear bomb peak with seasonal resolution, demonstrating an October–December 1965 maximum. This unequivocal radiocarbon signal offers a potential ‘golden spike’ to formalise the start of the Anthropocene and sheds light on interhemispheric transport and atmospheric mixing processes during a period of rapid industrialisation. These findings not only anchor geological stratigraphy but also enhance constraints on global carbon exchange rates at a time of unprecedented human impact.

Accelerator Mass Spectrometry Applications in Environmental Carbon Cycling publication trend

The graph below shows the total number of articles in accelerator mass spectrometry applications in environmental carbon cycling across all publications each year (not limited to Nature Index journals).

Technical terms

Accelerator Mass Spectrometry (AMS): A technique that uses a particle accelerator to count individual rare isotopes at ultra-low abundances, greatly enhancing detection sensitivity. Radiocarbon (14C): A naturally occurring radioactive isotope of carbon formed in the upper atmosphere, widely used to trace carbon cycling and date organic materials. Bomb peak: The pronounced increase in atmospheric 14C from nuclear weapons testing in the 1950s–1960s, serving as a precise chronological marker in environmental archives. Δ14C: The per mil deviation of a sample’s radiocarbon content from a modern standard, indicating enrichment or depletion relative to atmospheric levels. Anthropogenic CO2: Carbon dioxide produced by human activities—chiefly fossil fuel combustion and land-use change—distinguished in isotopic records by its lack of 14C. Earth system model boundary conditions: Historical isotope datasets (e.g. Δ14C, δ13C) used to initialise and evaluate coupled atmosphere–ocean–biosphere simulations of the carbon cycle.

References

1. A novel post-1950 CE atmospheric 14C record for the tropics using absolutely dated tree rings in the equatorial Amazon. The Science of The Total Environment (2024).
2. Compiled records of carbon isotopes in atmospheric CO2 for historical simulations in CMIP6. Geoscientific Model Development (2017).
3. Observations and modelling of the global distribution and long‐term trend of atmospheric 14CO2. Tellus B (2010).
4. Accelerator mass spectrometry: state of the art and perspectives. Advances in Physics X (2016).
5. Global Peak in Atmospheric Radiocarbon Provides a Potential Definition for the Onset of the Anthropocene Epoch in 1965. Scientific Reports (2018).
6. Evolution of natural and anthropogenic fluxes of atmospheric CO2 from 1957 to 2003. Tellus B (2011).