Soil organic matter transport along an sub-Arctic river-sea transect

► BHPs and GDGTs in an (sub-) Arctic river transect were analysed. ► BHP and GDGT based proxies indicate decreasing trends in an off-river direction. ► A new BHP based proxy, Rsoil′, is proposed to track soil derived carbon. ► Microbial biomarkers can be used to track soil derived carbon in (sub-) Arctic waters.