Subboreal aridity and scytonemin in the Holocene Black Sea

► Scytonemin is a diagnostic biomarker for cyanobacteria exposed to UV radiation. ► It is resistant to degradation and is preserved in deep sea sediments. ► C and N isotopes suggest scytonemin in the Black Sea was derived from desert soil. ► The Subboreal Phase in the Black Sea region was likely characterized by increased aridity.