Work

Stored carbohydrates buffer Bomb and Suess radiocarbon effects in maple leaves across a 65-year Ottawa region record

Year: 2026

Type: article

Abstract: As the Suess effect drives atmospheric radiocarbon (Δ 14 C) below zero, biological 14 C archives are increasingly biased by carbon-storage physiology. We show that sugar maple ( Acer saccharum ) leaves carry a systematic positive Δ 14 C offset relative to the ambient atmosphere because new foliage is built partly from stored non-structural carbohydrate (NSC) reserves that retain older, 14 C-enriched carbon. A 65-year record from Gatineau Park, Quebec, spanning the bomb-pulse peak (+ 842‰, 1964) to the Suess-effect zero-crossing, shows that the offset scaled with the rate of atmospheric decline, from + 34‰ during the rapid post-peak decline (1966–1998) to + 7‰ in 1999–2024. A two-endmember mixing model constrains the product of the stored fraction ( f ) and the mean age of stored carbon ( ${{\bar{\uptau }}}$ ) to ≈ 1.3–1.7 year, and for ${{\bar{\uptau }}} $ = 2–3 year, f = 0.5–0.7 (0.70 ± 0.27 for an exponential-age pool). The leaf Δ 14 C zero-crossing in 2024 lagged the atmospheric crossing by 2.2 ± 0.3 year, and the offset re-opened to + 11‰ in 2024 as the Suess-effect decline steepened. NSC storage must therefore be accounted for explicitly when interpreting leaf 14 C as an atmospheric proxy.

Source: Scientific Reports

DOI: 10.1038/s41598-026-76700-9

Authors: Leonard I. Wassenaar, Carley A. Crann, Sarah Murseli

Institution: University of Ottawa

Language: English

Topic: Archaeology and ancient environmental studies

Subfield: Archeology

Field: Social Sciences

Domain: Social Sciences

SDG: Climate action

Open Access status: gold

Estimated APC paid: $2,690