Terrestrial Biomolecular Burial Efficiencies on Continental Margins

This is the authors' abstract. We don't add key points for this paper.

The fate of terrestrial organic carbon (OCterr) exported from large rivers in marginal seas is an integral component of land‐ocean‐atmosphere carbon dynamics and influences on atmospheric CO2 concentrations on millennial and longer timescales. In this study, we employ a novel approach to constrain burial efficiencies for source‐specific terrestrial biomolecules (long‐chain n‐alkanes and n‐fatty acids) in two river‐marginal sea systems. We find for the Pearl River‐South China Sea system that 34 ± 19% and 11 ± 4% of n‐alkanes and n‐fatty acids, respectively, are preserved across the transport pathway from the river mouth to inner shelf. In contrast, terrestrial biomolecular burial efficiencies were markedly higher (64 ± 17% and 84 ± 30% of n‐alkanes and n‐fatty acids, respectively) in the Yellow River‐Bohai Sea/Yellow Sea system. These findings reveal markedly different fates of OCterr in these two fluvial‐marine systems, as well as sharp contrasts in OCterr reactivity within each system.