234Th-derived surface export fluxes of POC from the Northern Barents Sea and the Eurasian sector of the Central Arctic Ocean

► Biogeochemically-consistent POC export fluxes in high Eurasian Arctic. ► Successful demonstration of at sea low volume direct beta counting for 234Th proxy. ► 3-5 times higher POC fluxes in marginal ice zone than in multi-year ice inner Arctic. ► No distinction in POC export efficiency (ThE ratio) between MIZ and MYI regimes.