Methoxy-serratenes in a soil under conifers and their potential use as biomarkers of Pinaceae

In the frame of a study aimed at defining new soil molecular biomarkers that could attest to former land use and that could also be screened in lake sediments for palaeoenvironmental reconstruction, we analysed the 2–4 cm depth layer of a soil developed under a conifer forest in the Lake Aydat catchment (French Massif Central). The lipid fraction of the sample contained 12 serratenoids bearing at least a methoxyl (OMe) group at C-3 or C-21 and various additional functional groups (alcohol, ketone or acetate). A survey of the literature provided indubitable evidence that these compounds are typical for Pinaceae species, in agreement with the surrounding vegetation at the sampling site. Due to the economic and ecological importance of the taxa, the presence of these highly specific compounds in soil, sediments or peat could therefore help in unravelling the timing of forestry activity.