Benthic ostracode δ13C as sensor for early Holocene establishment of modern circulation patterns in Central Europe

► Species-specific δ13C of benthic ostracode species reflects methanogenesis. ► δ13C of ostracodes is related to methanogenesis. ► Early Holocene shift in δ13C is related to establishment of NAO. ► δ13C as new proxy for climate change.