Sprecher
Beschreibung
Solar ultraviolet-B (UV-B; 280–315 nm) radiation plays a fundamental role in terrestrial ecosystem processes, yet long-term terrestrial records of past UV-B variability remain limited, particularly in mid-latitude regions. This study develops and applies a chemo-palynological approach based on attenuated total reflection Fourier Transform Infrared (ATR micro-FTIR) microspectroscopy to reconstruct past UV-B flux using ultraviolet-absorbing compounds (UACs) preserved in Quercus pollen.
Methodological analyses demonstrate that ATR micro-FTIR applied to individual pollen grains or small grain clusters produces more reproducible spectra and minimizes distortion compared with conventional transmission FTIR techniques. In contrast to the widely used and highly dispersive Pinus pollen, Quercus pollen derives from more spatially constrained source areas and possesses chemically resistant sporopollenin, making it a robust and regionally representative archive of past UV-B exposure.
The method was applied to a mid–late Holocene sediment core from Crovani Pond (Corsica, France), generating the first continuous terrestrial UV-B reconstruction for the Mediterranean mid-latitudes. Variations in UAC indices closely correspond with established solar activity proxies, including cosmogenic isotopes, total solar irradiance, and sunspot numbers, as well as regional sea-surface temperature records. Major climatic intervals, such as the Medieval Climate Anomaly and the Spörer Minimum, are clearly expressed in the reconstruction.