Assessing the effect of ground saturation on strontium and sulfur biosphere values in plants from south Wales

This study evaluates the influence of contrasting hydrological conditions on strontium (Sr) and sulfur (S) isotope compositions in plants across south Wales. Samples collected during an exceptionally wet period in spring 2013 are compared with those collected during drought conditions in summer 2018. Despite the expectation that variable groundwater saturation would significantly alter biosphere isotope signatures, results indicate broadly consistent 87 Sr/ 86 Sr and δ 34 S values between the two sampling periods. Notable deviations are restricted to rush (Juncaceae) samples, which show sensitivity to water availability. The average site-level variability (1 SD) is ± 0.0007 for 87 Sr/ 86 Sr and ± 1.0 ‰ for δ 34 S (excluding rush samples). These findings suggest that short-term climatic variability exerts only a limited influence on biosphere isotope baselines relevant to archaeological and forensic applications.