Synchronous Marine and Terrestrial Carbon Cycle Perturbation in the High Arctic During the PETM

The Paleocene-Eocene Thermal Maximum (PETM; 56 Ma) is considered to be one of the best analogs for future climate change. carbon isotope composition (δ13C) n-alkanes derived from leaf waxes terrestrial plants and marine algae can provide important insights into cycle perturbation during PETM. Here, we present new organic geochemical data compound-specific δ13C sediments recovered an early Cenozoic basin-margin succession Spitsbergen. These samples represent most expanded PETM sites high Arctic response Our results reveal a synchronous ∼−6.5‰ excursion (CIE) in short-chain (nC19; algae/bacteria) with ∼−5‰ CIE long-chain (nC29 nC31; plant waxes) peak Although δ13Cn-alkanes values were potentially affected via modest thermal effect (1‰–2‰), relative changes remain robust. A simple modeling suggests emission rate could ∼3 times faster than previously suggested using δ13CTOC records. magnitude both n-C19 δ13Cn-C29 explained by elevated influence 13C-depleted respired CO2 water column increased availability on land, pCO2 atmosphere, vegetation type decline algae/bacteria argues against significant contribution sedimentary pool weathering delivery fossil region.