European Palaeobotany and Palynology Conference 2026

Ultraviolet-B (UV-B) radiation and its variation on the ground acts as regulator and stressor for terrestrial ecosystems. This study investigates variability in past surface UV-B radiation in northwest England during the Common Era by analysing ultraviolet-absorbing compounds (UACs) in sub-fossil Sphagnum spores extracted from a Late Holocene peat bog. We present a bidecadally-resolved record of UACs for the last 2600 years, providing first insights into past surface UV-B radiation. We compare our record with a previous, highly-resolved record of Sphagnum leaf δ18O and bog surface wetness, and find a significant correlation where lower UAC signals are found during wetter bog conditions, indicating associations between radiative and drought forcing. We also find that some UAC minima correspond to recognised Grand Solar Minima in late Holocene, but this association is not consistent across the whole timescale investigated. Our findings suggest more complex mechanisms underlying the relationship between solar activity and Sphagnum UACs. The research contributes to understanding the complex interplay between solar forcing, climate dynamics, and surface UV-B radiation over peatlands.