Influence of common palynological extraction treatments on ultraviolet absorbing compounds (UACs) in sub-fossil pollen and spores observed in FTIR spectra

Introduction Biological life, atmospheric circulation and the Earth’s climate may be influenced by UV-B radiation. In plants, Ultraviolet Absorbing Compounds (UACs) are an indicator of exposure, abundance UACs in pollen spores embryophytes is measurable using Fourier Transform Infrared (FTIR) micro-Spectroscopy. However, understanding influence common chemical pre-treatments on sub-fossil with a view to reconstruction still requires investigation. Methods Here, peat samples collected from Late Holocene raised bog were treated different chemicals (HCl, KOH, acetolysis) for varying treatment times (up 210 min). Pollen or three taxa ( Alnus , Calluna Sphagnum ) isolated FTIR spectra obtained individual grains. The compared modern spore nearby. Results Spectra show several visible differences related lipid protoplast contents. results treatments reveal that HCl produced limited changes, while KOH acetolysis altered peaks, including UAC-related aromatic peak at 1516 cm −1 . We observe all modify some degree, weakest (HCl) strongest (acetolysis). With respect reduction UAC area time, we cases significant log-decay relationship, notably spores. Compared untreated control samples, reduced 68%, 69% 60% respectively, after only 3 min treatment. After 60 minutes peaks 77%, 84% 88%. Discussion Due potential taxon-specific effects reductions even within short times, our recommendation future applications palaeoecological studies palynomorph chemistry avoid digestions extraction process favour separation methods micro-sieving density separation.