- 1Department of Ocean Science and Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Hong Kong, China (yuanbiyi@ust.hk; crh1987@163.com; dinghe@ust.hk)
- 2Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, 26129, Oldenburg, Germany (atanentzap@trentu.ca)
- 3Ecosystems and Global Change Group, School of the Environment, Trent University, Peterborough, ON K9L 0G2, Canada (atanentzap@trentu.ca)
- 4State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing, China (hechen@cup.edu.cn; sq@cup.edu.cn)
- 5Department of Global Ecology, Carnegie Institution for Science, Stanford, California, USA (jmerder@carnegiescience.edu)
- 6Marine Chemistry, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Rostock, Germany (helena.osterholz@io-warnemuende.de)
- 7State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China (baohy@xmu.edu.cn)
- 8Department of Chemistry, BMC, Uppsala University, Sweden (jeffrey.hawkes@kemi.uu.se)
- 9Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, China (siliang.li@tju.edu.cn; sheng.xu@tju.edu.cn)
- 10Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, China (zhangcl@sustech.edu.cn)
- 11Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China (zhangcl@sustech.edu.cn)
- 12Shanghai Sheshan National Geophysical Observatory, Shanghai, China (zhangcl@sustech.edu.cn)
- 13Frontiers Science Center for Deep Ocean Multispheres and Earth System of the Ministry of Education, Ocean University of China, Qingdao, 266100, China (maxzhao@ouc.edu.cn)
- 14Laoshan Laboratory, Qingdao, 266237, China (maxzhao@ouc.edu.cn)
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 2 to 3 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 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 molecular formulae to dissolved organic carbon concentrations, we estimated that a mean of 21.7 (16.7-25.0)% of oceanic DOM is likely derived from rivers.
How to cite: Yi, Y., Tanentzap, A., He, C., Merder, J., Osterholz, H., Bao, H., Hawkes, J., Cai, R., Li, S., Shi, Q., Xu, S., Zhang, C., Zhao, M., and He, D.: Underestimated input of terrestrial dissolved organic carbon to the ocean, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7651, https://doi.org/10.5194/egusphere-egu25-7651, 2025.
