The fate of terrestrial organic carbon (OC_terr) 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 OC_terr in these two fluvial‐marine systems, as well as sharp contrasts in OC_terr reactivity within each system.

中文翻译：

---

大陆边缘的陆地生物分子掩埋效率

从边缘海中的大河流出口的陆地有机碳（OC _terr）的命运是陆地-海洋-大气碳动态的一个不可或缺的组成部分，并且对千禧年及更长时期的大气中CO ₂浓度产生影响。在这项研究中，我们采用了一种新颖的方法来限制两个河流边缘海系统中特定于源头的陆地生物分子（长链正构烷烃和正构脂肪酸）的埋葬效率。对于珠江南海系统，我们发现正构烷烃和正构烷烃中有34±19％和11±4％脂肪酸分别保留在从河口到内陆架的整个运输路径中。相反，在黄河-渤海/黄海系统中，陆地生物分子掩埋效率显着更高（分别为正烷烃和正脂肪酸的64±17％和84±30％）。这些发现揭示了这两个河流海洋系统中OC _terr的命运显着不同，以及每个系统中OC _terr反应性的强烈对比。