Biomarkers as paleoclimate proxies in peatlands in coastal high plains in Asturias, N Spain

Biomarkers have revealed the widespread occurrence of nonadecan-2-one (K19), a characteristic of Cantabrian peatlands, different periods of dominance by higher plants and bacterial triterpenoids and an alternance of humid and dry periods as reflected in the n-alkane ratios. A change from a more arboreous vegetation before 4000 cal. yr BP in the relatively dry warm climate of the Middle Holocene to a Sphagnum-herbaceous dominant vegetation typical of cooler wetter conditions is observed. The wet episode between 2200 and 3000 cal. yr BP has a widespread occurrence in the studied profiles, whereas other dry-wet episodes are only recorded in some peat deposits and may be associated with local conditions.