近日，香港科技大学何丁团队报道了陆地溶解有机碳向海洋的输入低于此前估计。这一研究成果发表在2025年11月3日出版的《美国科学院院刊》杂志上。
陆地溶解有机物（DOM）对海洋的贡献几十年来一直是个谜。由于陆地生物标志物的不稳定性、生物地球化学分选的碳同位素难以区分以及陆地和海洋DOM之间相似的化学成分等因素，跟踪海洋中的陆地DOM已被证明具有挑战性。
研究组发现，陆地对海洋有机碳库的贡献是先前假设的1.7至2.5倍，这突出了调整全球碳循环模型的必要性。研究组通过连接高效液相色谱法和超高分辨率质谱法来研究从河流输送到海洋的陆地分子的存在，并估计它们对海洋DOM的贡献，得出了这些估计。
研究组鉴定出269种可能从陆地输送到海洋的分子式。这些分子式在培养实验中表现出对生物和光化学降解的抗性，并广泛分布于全球河流、边缘海和开阔大洋中，表明它们在内陆与海洋水体中普遍存在且具有同源性。通过将陆源分子式的丰度与溶解有机碳浓度及放射性碳测量数据相关联，研究组估算得出河流可能贡献了海洋溶解有机质总量的16.7%至25.0%。
附：英文原文
Title: Underestimated input of terrestrial dissolved organic carbon to the ocean
Author: Yi, Yuanbi, Tanentzap, Andrew J., He, Chen, Merder, Julian, Osterholz, Helena, Bao, Hongyan, Hawkes, Jeffrey A., Cai, Ruanhong, Li, Si-Liang, Shi, Quan, Xu, Sheng, Zhang, Chuanlun, Liu, Cong-Qiang, Zhao, Meixun, He, Ding
Issue&Volume: 2025-11-3
Abstract: The contribution of terrestrial dissolved organic matter (DOM) to the ocean has been an enigma for decades. Tracking terrestrial DOM in the ocean has proven challenging due to factors such as the instability of terrestrial biomarkers, indistinguishable carbon isotopes from biogeochemical fractionation, and similar chemical composition between terrestrial and oceanic DOM. Here, we show that the terrestrial contribution to oceanic organic carbon pools is 1.7 to 2.5 times higher than previously assumed, highlighting the need to adjust global carbon cycle models. We derive these estimates by bridging high-performance liquid chromatography with ultra-high resolution mass spectrometry to investigate the presence of terrestrial molecules that are transported from rivers to the ocean and estimate their contribution to oceanic DOM. We identified 269 molecular formulae (MF) that are likely transported from land to the ocean. These formulae exhibited resistance to biological and photochemical degradation in incubation experiments, and were widely distributed in global rivers, marginal seas, and open oceans, suggesting that they are ubiquitous in inland and ocean waters and have a similar source. By relating the abundances of terrestrially derived MF to dissolved organic carbon concentrations, and radiocarbon measurements, we estimated that 16.7 to 25.0% of oceanic DOM is likely derived from rivers.
DOI: 10.1073/pnas.2505838122
Source: https://www.pnas.org/doi/abs/10.1073/pnas.2505838122