Contrasting variations in the structure and stable carbon isotopic composition of botryococcenes through the last glacial-interglacial transition in Lake Masoko (southern Tanzania)

► The glacial/interglacial occurrence of botryococcenes shows sharp variation. ► Methylated and cyclic botryococcenes formed under contrasting climatic conditions. ► Structurally-related botryococcenes can have distinct 13C composition. ► Environmental controls on botryococcene biosynthesis are complex. ► Botryococcene composition may be strongly influenced by local environmental parameters.