Carbon isotopes ( ¹⁴ C, ¹³ C) of Gatersleben plant tissues ( Triticum aestivum L., Glycine max (L.) Merr.) grown during the bomb spike

Here we present an updated version of radiocarbon concentrations measured in seeds from the Gatersleben Crop Plant Research institute. 14 C-isotope measurements for wheat from 1946 to 2020, which were presented previously, have been complemented with 14 C measurements made on soybean and continued until late summer 2025. Additionally, we measured δ 13 C in wheat samples. A comparison of different 14 C time series over the last 80 years from different regions such as the Colorado Plateau (herbaria archived annual plants; Carbone et al. 2023), England (Barley; Dunbar et al. 2024), and Germany (Gatersleben seed, this study) reveal 14 C discrepancies during peak bomb-period with reference atmospheric 14 C data, i.e., the Northern Hemisphere Zone 1 & 2, and may indicate a heterogenous atmospheric 14 C composition, i.e., admixture of different air masses with a slightly divergent 14 C composition.