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Tracing the source of dissolved organic carbon in rivers by carbon isotope (Δ14C-δ13C): A case study of Tianyu River in Qinling Mountains, China
Published online by Cambridge University Press: 21 August 2025
Abstract
The cycling of carbon in riverine systems is a critical component of global carbon cycle research. However, the sources and performances of riverine carbon in the Qinling Mountains, a pivotal hydrological nexus in China, remain poorly understood. This study investigates the seasonal variations of dissolved organic carbon (DOC) concentration in the Tianyu River within the Qinling Mountains. By utilizing a combination of carbon isotopic signatures (Δ14C-δ13C) and the stepped-combustion method, we examined the sources of DOC and the contribution ratio of each end-member. Our findings reveal that: (1) the concentrations and dual carbon isotope ratios of DOC in the Tianyu River are influenced by regional climatic factors, exhibiting distinct seasonal patterns; (2) the 14C age of DOC in the Tianyu River is comparatively older than the global average for rivers but younger than that of China’s three major rivers (the Yellow, Yangtze, and Pearl Rivers); and (3) the DOC mainly comes from exogenous sources, with a proportion of about 85.8%–88.4%. Vegetation and riverine sediments are identified as primary contributors. These findings suggest that exemplary ecological preservation exists within the Qinling region while operating within an efficient carbon cycling system. This investigation provides initial insights into how regional climatic conditions influence riverine carbon cycles and enhances our understanding of biogeochemical processes related to carbon.
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- © The Author(s), 2025. Published by Cambridge University Press on behalf of University of Arizona
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a
Both authors contribute equally to this work.
References
Amon, RMW, Rinehart, AJ, Duan, S, Louchouarn, P, Prokushkin, A, Guggenberger, G, Bauch, D, Stedmon, C, Raymond, PA, Holmes, RM et al (2012) Dissolved organic matter sources in large Arctic Rivers. Geochimica et Cosmochimica Acta 94, 217–237.CrossRefGoogle Scholar
Battin, TJ, Lauerwald, R, Bernhardt, ES, Bertuzzo, E, Gener, LG, Hall, RO, Hotchkiss, ER, Maavara, T, Pavelsky, TM, Ran, L et al (2023) River ecosystem metabolism and carbon biogeochemistry in a changing world. Nature 613(7944), 449–459.CrossRefGoogle Scholar
Borken, W, Ahrens, B, Schulz, C and Zimmermann, L (2011) Site-to-site variability and temporal trends of DOC concentrations and fluxes in temperate forest soils. Global Change Biology 17(7), 2428–2443.CrossRefGoogle Scholar
Chaplot, V and Mutema, M (2021) Sources and main controls of dissolved organic and inorganic carbon in river basins: A worldwide meta-analysis. Journal of Hydrology 603, 126941.CrossRefGoogle Scholar
Chen, S, Zhong, J, Li, C, Liu, J, Wang, W, Xu, S and Li, S-L (2021) Coupled effects of hydrology and temperature on temporal dynamics of dissolved carbon in the Min River, Tibetan Plateau. Journal of Hydrology 593, 125641.Google Scholar
Cheng, P, Burr, GS, Zhou, W, Chen, N, Hou, Y, Du, H, Fu, Y and Lu, X (2020) The deficiency of organic matter 14C dating in Chinese loess-paleosol sample. Quaternary Geochronology 56, 101051.CrossRefGoogle Scholar
Cheng, P, Dong, J, Zhou, W, Song, Y, Zhou, J, Fan, Y, Lan, J, Xian, F, Hou, Y, Chen, N et al (2022) Paleoclimatic implications of 14C age deviations in loess organic matter from Xinjiang, Northwest China. CATENA 212, 106096.CrossRefGoogle Scholar
Cheng, P and Fu, Y (2020) Stepped-combustion 14C dating in loess-paleosol sediment. Radiocarbon 62(5), 1209–1220.CrossRefGoogle Scholar
Cheng, P, Zhou, W, Wang, H, Lu, X and Du, H (2013)
14C dating of soil organic carbon (SOC) in loess-paleosol using sequential pyrolysis and accelerator mass spectrometry (AMS). Radiocarbon 55(2), 563–570.CrossRefGoogle Scholar
Couture, S, Houle, D and Gagnon, C (2012) Increases of dissolved organic carbon in temperate and boreal lakes in Quebec, Canada. Environmental Science and Pollution Research 19(2), 361–371.CrossRefGoogle ScholarPubMed
Cui, X, Mucci, A, Bianchi, TS, He, D, Vaughn, D, Williams, EK, Wang, C, Smeaton, C, Koziorowska-Makuch, K, Faust, JC et al (2022) Global fjords as transitory reservoirs of labile organic carbon modulated by organo-mineral interactions. Science Advances 8(46), eadd0610.Google ScholarPubMed
Dong, Y, Li, Y, Kong, F, Zhang, J and Xi, M (2020) Source, structural characteristics and ecological indication of dissolved organic matter extracted from sediments in the primary tributaries of the Dagu River. Ecological Indicators 109, 105776.CrossRefGoogle Scholar
Dosskey, MG and Bertsch, PM (1994) Forest sources and pathways of organic matter transport to a blackwater stream: A hydrologic approach. Biogeochemistry 24(1), 1–19.CrossRefGoogle Scholar
Fu, W, Xu, X, Druffel, EM, Wang, X, Sun, S, Luo, C, Zhang, H and Fan, D (2022) Carbon isotopic constraints on the degradation and sequestration of organic matter in river-influenced marginal sea sediments. Limnology and Oceanography 67(S2), S61–S75.CrossRefGoogle Scholar
Fu, Y, Tang, C, Li, J, Zhao, Y, Zhong, W and Zeng, X (2014) Sources and transport of organic carbon from the Dongjiang River to the Humen outlet of the Pearl River, Southern China. Journal of Geographical Sciences 24(1), 143–158.CrossRefGoogle Scholar
Gao, Q, Shen, C, Sun, Y and Yi, W (2001) A preliminary study on the organic carbon weathering fluxes in Beijiang River drainage. Environmental Science (2), 12–18.Google Scholar
Gao, Y, Jia, J, Lu, Y, Yang, T, Lyu, S, Shi, K, Zhou, F and Yu, G (2021) Determining dominating control mechanisms of inland water carbon cycling processes and associated gross primary productivity on regional and global scales. Earth-Science Reviews 213, 103497.CrossRefGoogle Scholar
Gu, Z, Liu, Q, Xu, B, Han, J, Yang, S, Ding, Z and Liu, T (2003) Climate as the dominant control on C3 and C4 plant abundance in the loess plateau: Organic carbon isotope evidence from the last glacial-interglacial loess-soil sequences. Chinese Science Bulletin 48(12), 1271–1276.Google Scholar
Guo, L, Santschi, PH, Cifuentes, LA, Trumbore, SE and Southon, J (1996) Cycling of high-molecular-weight dissolved organic matter in the Middle Atlantic Bight as revealed by carbon isotopic (13C and 14C) signatures. Limnology and Oceanography 41(6), 1242–1252.CrossRefGoogle Scholar
Hamilton, LS (1992) The protective role of mountain forests. GeoJournal 27(1), 13–22.CrossRefGoogle Scholar
Hanba, YT, Kobayashi, T and Enomoto, T (2010) Variations in the foliar δ13C and C3/C4 species richness in the Japanese flora of poaceae among climates and habitat types under human activity. Ecological Research 25(1), 213–224.CrossRefGoogle Scholar
He, B, Dai, M, Zhai, W, Wang, L, Wang, K, Chen, J, Lin, J, Han, A and Xu, Y (2010) Distribution, degradation and dynamics of dissolved organic carbon and its major compound classes in the Pearl River estuary, China. Marine Chemistry 119(1), 52–64.Google Scholar
Heaton, TJ, Bronk Ramsey, C, Butzin, M, Köhler, P, Muscheler, R, Reimer, PJ and Wacker, L (2021). Radiocarbon: A key tracer for studying Earth’s dynamo, climate system, carbon cycle, and sun. Science (New York, NY) 374(6568).Google ScholarPubMed
Hemingway, JD, Rothman, DH, Grant, KE, Rosengard, SZ, Eglinton, TI, Derry, LA and Galy, VV (2019) Mineral protection regulates long-term global preservation of natural organic carbon. Nature 570(7760), 228–231.CrossRefGoogle ScholarPubMed
Hemingway, JD, Rothman, DH, Rosengard, SZ and Galy, VV (2017) Technical note: An inverse method to relate organic carbon reactivity to isotope composition from serial oxidation. Biogeosciences 14(22).Google Scholar
Kang, S, Kim, J-H, Ryu, J-S and Shin, K-H (2020) Dual carbon isotope (δ13C and δ14C) characterization of particulate organic carbon in the Geum and Seomjin estuaries, South Korea. Marine Pollution Bulletin 150, 110719.CrossRefGoogle ScholarPubMed
Keaveney, EM, Reimer, PJ and Foy, RH (2015a) Young, old, and weathered carbon-part 1: Using radiocarbon and stable isotopes to identify carbon sources in an alkaline, humic lake. Radiocarbon 57(3), 407–423.CrossRefGoogle Scholar
Keaveney, EM, Reimer, PJ and Foy, RH (2015b) Young, old, and weathered carbon-part 2: Using radiocarbon and stable isotopes to identify terrestrial carbon support of the food web in an alkaline, humic lake. Radiocarbon 57(3), 425–438.Google Scholar
Lai, M, Zhong, J, Wang, W, Yi, Y, Chen, R and Xu, S (2021) Spatial distribution, sources and controlling factors of dissolved organic carbon of Bailong River. Earth and Environment 49(03), 227–237.Google Scholar
Lal, R (2013) Soil carbon management and climate change. Carbon Management 4(4), 439–462.CrossRefGoogle Scholar
Lan, X (2018) The Tianyu watershed vegetation spatial pattern optimization of Qinling national botanical garden based on the plant community evaluation. Master’s thesis, Xi’an University of Architecture and Technology.Google Scholar
Lee, L-C, Hsu, T-C, Lee, T-Y, Shih, Y-T, Lin, C-Y, Jien, S-H, Hein, T, Zehetner, F, Shiah, F-K and Huang, J-C (2019) Unusual roles of discharge, slope and SOC in DOC transport in small mountainous rivers, Taiwan. Scientific Reports 9(1), 1574.CrossRefGoogle ScholarPubMed
Li, F (2022) Dual carbon isotope tracing of dissolved organic carbon sources in natural reservoirs and artificial lakes in Guiyang. Master’s thesis, Guizhou University.Google Scholar
Li, S, Meng, L, Zhao, C, Gu, Y, Spencer, RGM, Álvarez-Salgado, XA, Kellerman, AM, McKenna, AM, Huang, T, Yang, H et al (2023) Spatiotemporal response of dissolved organic matter diversity to natural and anthropogenic forces along the whole mainstream of the Yangtze River. Water Research 234, 119812.CrossRefGoogle ScholarPubMed
Liu, F and Wang, D (2021) Dissolved organic carbon concentration and biodegradability across the global rivers: A meta-analysis. Science of The Total Environment 151828.Google Scholar
Liu, T, Zhou, W, Cheng, P and Burr, GS (2018) A survey of the 14C content of dissolved inorganic carbon in Chinese lakes. Radiocarbon 60(2), 705–716.Google Scholar
Liu, W and Xing, M (2012) Isotopic indicators of carbon and nitrogen cycles in river catchments during soil erosion in the arid loess plateau of China. Chemical Geology 296–297, 66–72.CrossRefGoogle Scholar
Liu, Z, Deng, Z, He, G, Wang, H, Zhang, X, Lin, J, Qi, Y and Liang, X (2022) Challenges and opportunities for carbon neutrality in China. Nature Reviews Earth & Environment 3(2), 141–155.Google Scholar
Long, X (2007) Research on tourism landscape ecological planning & design of Tianyu drainage area in Shaanxi province. Master’s thesis, Shaanxi Normal University.Google Scholar
Ma, Q, Jin, H, Wu, Q, Yang, Y, Wang, Q, Luo, D, Huang, Y, Li, Y, Li, X, Serban, RD et al (2022) Distributive features of dissolved organic carbon in aquatic systems in the source area of the yellow river on the Northeastern Qinghai–Tibet Plateau, China. Frontiers in Earth Science 10.CrossRefGoogle Scholar
Ma, Y and Li, S (2020) Spatial and temporal comparisons of dissolved organic matter in river systems of the three gorges reservoir region using fluorescence and UV–Visible spectroscopy. Environmental Research 189, 109925.CrossRefGoogle ScholarPubMed
Marwick, TR, Tamooh, F, Teodoru, CR, Borges, AV, Darchambeau, F and Bouillon, S (2015) The age of river-transported carbon: A global perspective. Global Biogeochem Cycles 29(2), 122–137.CrossRefGoogle Scholar
Mayorga, E, Aufdenkampe, AK, Masiello, CA, Krusche, AV, Hedges, JI, Quay, PD, Richey, JE and Brown, TA (2005) Young organic matter as a source of carbon dioxide outgassing from amazonian rivers. Nature 436(7050), 538–541.CrossRefGoogle ScholarPubMed
McCallister, SL, Bauer, JE, Cherrier, JE and Ducklow, HW (2004) Assessing sources and ages of organic matter supporting river and estuarine bacterial production: A multiple-isotope (δ14C, δ13C, and δ15N) approach. Limnology and Oceanography 49(5), 1687–1702.CrossRefGoogle Scholar
McCarthy, MD, Beaupré, SR, Walker, BD, Voparil, I, Guilderson, TP and Druffel, ERM (2011) Chemosynthetic origin of 14C-depleted dissolved organic matter in a ridge-flank hydrothermal system. Nature Geoscience 4(1), 32–36.CrossRefGoogle Scholar
McGeehin, J, Burr, GS, Hodgins, G, Bennett, SJ, Robbins, JA, Morehead, N and Markewich, H (2004) Stepped-combustion 14C dating of bomb carbon in lake sediment. Radiocarbon 46(2), 893–900.CrossRefGoogle Scholar
McGeehin, J, Burr, GS, Jull, AJT, Reines, D, Gosse, J, Davis, PT, Muhs, D and Southon, JR (2001) Stepped-combustion 14C dating of sediment: A comparison with established techniques. Radiocarbon 43(2A), 255–261.CrossRefGoogle Scholar
McNichol, AP and Aluwihare, LI (2007) The power of radiocarbon in biogeochemical studies of the marine carbon cycle: Insights from studies of dissolved and particulate organic carbon (DOC and POC). ChemInform 38(24).CrossRefGoogle Scholar
Moreira-Turcq, P, Bonnet, M-P, Amorim, M, Bernardes, M, Lagane, C, Maurice, L, Perez, M and Seyler, P (2013) Seasonal variability in concentration, composition, age, and fluxes of particulate organic carbon exchanged between the floodplain and amazon river. Global Biogeochem Cycles 27(1), 119–130.CrossRefGoogle Scholar
Ni, M and Li, S (2022) Dynamics and internal links of dissolved carbon in a karst river system: Implications for composition, origin and fate. Water Research 226, 119289.CrossRefGoogle Scholar
Phillips, D, Inger, R, Bearhop, S, Jackson, A, Moore, J, Parnell, A, Semmens, B and Ward, E (2014) Best practices for use of stable isotope mixing models in food-web studies. Canadian Journal of Zoology 92.CrossRefGoogle Scholar
Phillips, DL (2001) Mixing models in analyses of diet using multiple stable isotopes: A critique. Oecologia 127(2), 166–170.CrossRefGoogle Scholar
Raymond, PA and Bauer, JE (2001a) DOC cycling in a temperate estuary: A mass balance approach using natural 14C and 13C isotopes. Limnology and Oceanography 46(3), 655–667.CrossRefGoogle Scholar
Raymond, PA and Bauer, JE (2001b) Use of 14C and 13C natural abundances for evaluating riverine, estuarine, and coastal DOC and POC sources and cycling: A review and synthesis. Organic Geochemistry 32(4), 469–485.CrossRefGoogle Scholar
Repasch, M, Scheingross, JS, Hovius, N, Lupker, M, Wittmann, H, Haghipour, N, Gröcke, DR, Orfeo, O, Eglinton, TI and Sachse, D (2021) Fluvial organic carbon cycling regulated by sediment transit time and mineral protection. Nature Geoscience 14(11), 842–848.CrossRefGoogle Scholar
Rosenheim, BE, Day, MB, Domack, E, Schrum, H, Benthien, A and Hayes, JM (2008) Antarctic sediment chronology by programmed-temperature pyrolysis: Methodology and data treatment. Geochem Geophys Geosyst 9(4).CrossRefGoogle Scholar
Rosenheim, BE and Galy, V (2012) Direct measurement of riverine particulate organic carbon age structure. Geophys Res Lett 39(19).CrossRefGoogle Scholar
Schiff, SL, Aravena, R, Trumbore, SE, Hinton, MJ, Elgood, R and Dillon, PJ (1997) Export of DOC from forested catchments on the Precambrian Shield of Central Ontario: Clues from 14C and 13C. Biogeochemistry 36(1), 43–65.CrossRefGoogle Scholar
Shan, S, Qi, Y, Luo, C, Fu, W, Xue, Y and Wang, X (2020) Carbon isotopic constrains on the sources and controls of the terrestrial carbon transported in the four large rivers in China. Advances in Earth Science 35(9), 948–961.Google Scholar
Shen, M, Zhang, Y and Chen, Y (2001) Vegetation of the Tianyuhe River valley in Qinling Mountain. Acta Botanica Boreali-Occidentalia Sinica 3, 532–537.Google Scholar
Soria-Reinoso, I, Alcocer, J, Sánchez-Carrillo, S, García-Oliva, F, Cuevas-Lara, D, Cortés-Guzmán, D and Oseguera, LA (2022) The seasonal dynamics of organic and inorganic carbon along the tropical Usumacinta River basin (Mexico). Water 14(17). doi: 10.3390/w14172703.CrossRefGoogle Scholar
Srivastava, RK, Shetti, NP, Reddy, KR, Kwon, EE, Nadagouda, MN and Aminabhavi, TM (2021) Biomass utilization and production of biofuels from carbon neutral materials. Environmental Pollution 276, 116731.CrossRefGoogle ScholarPubMed
Striegl, RG, Dornblaser, MM, Aiken, GR, Wickland, KP and Raymond, PA (2007) Carbon export and cycling by the Yukon, Tanana, and Porcupine rivers, Alaska, 2001–2005. Water Resour Res 43(2).CrossRefGoogle Scholar
Stuiver, M and Polach, HA (1977) Discussion: Reporting of 14C data. Radiocarbon 19(3), 355–363.CrossRefGoogle Scholar
Takaki, Y, Hattori, K and Yamashita, Y (2022) Factors controlling the spatial distribution of dissolved organic matter with changes in the C/N ratio from the upper to lower reaches of the Ishikari River, Japan. Frontiers in Earth Science 10.CrossRefGoogle Scholar
Tranvik, L, Cole, JJ and Prairie, YT (2018) The study of carbon in inland waters-from isolated ecosystems to players in the global carbon cycle. Limnology and Oceanography Letters 3(3), 41–48.CrossRefGoogle Scholar
Wakeham, SG, McNichol, AP, Kostka, JE and Pease, TK (2006) Natural-abundance radiocarbon as a tracer of assimilation of petroleum carbon by bacteria in salt marsh sediments. Geochimica et Cosmochimica Acta 70(7), 1761–1771.CrossRefGoogle Scholar
Wang, H, Hackley, KC, Panno, SV, Coleman, DD, Liu, JCL and Brown, J (2003) Pyrolysis-combustion 14C dating of soil organic matter. Quaternary Research 60(3), 348–355.CrossRefGoogle Scholar
Wang, S-L, Burr, GS, Wang, P-L, Lin, L-H and Nguyen, V (2016) Tracing the sources of carbon in clay minerals: An example from western Taiwan. Quaternary Geochronology 34, 24–32.CrossRefGoogle Scholar
Wang, X, Ma, H, Li, R, Song, Z and Wu, J (2012) Seasonal fluxes and source variation of organic carbon transported by two major Chinese rivers: The Yellow River and Changjiang (Yangtze) River. Global Biogeochem Cycles 26(2).CrossRefGoogle Scholar
Wang, Y (2020) Study of Tracing the Sources of Dissolved Organic Carbon in Natural Reservoir and Artificial Lake by Carbon Isotopes. Institute of Earth Environment, Chinese Academy of Sciences.Google Scholar
Wei, X (2003) Study on Riverine Carbon Flux and Erosion of Zhujiang (Pearl) River Drainage Basin. Guangzhou Institute of Geochemistry, Chinese Academy of Sciences.Google Scholar
Wei, X, Li, N, Shen, C and Guo, Z (2011) Riverine organic carbon content and significance of carbon isotopic composition in the Xijiang River, China. Scientia Geographica Sinica 31(2), 166–171.Google Scholar
Wen, Y, Xiao, M, Chen, Z, Zhang, W and Yue, F (2023) Seasonal variations of dissolved organic matter in urban rivers of Northern China. Land 12(2). doi: 10.3390/land12020273.CrossRefGoogle Scholar
Wohlfart, C, Kuenzer, C, Chen, C and Liu, G (2016) Social-ecological challenges in the Yellow River basin (China): A review. Environmental Earth Sciences 75(13), 1066.CrossRefGoogle Scholar
Xue, Y, Zou, L, Ge, T and Wang, X (2017) Mobilization and export of millennial-aged organic carbon by the Yellow River. Limnology and Oceanography 62(S1), S95–S111.CrossRefGoogle Scholar
Yadav, A and Pandey, J (2017) Contribution of point sources and non-point sources to nutrient and carbon loads and their influence on the trophic status of the Ganga River at Varanasi, India. Environmental Monitoring and Assessment 189(9), 475.CrossRefGoogle ScholarPubMed
Yamori, W, Hikosaka, K and Way, DA (2014) Temperature response of photosynthesis in C3, C4, and CAM plants: Temperature acclimation and temperature adaptation. Photosynthesis Research 119(1), 101–117.CrossRefGoogle ScholarPubMed
Yang, X (2012) Hydrological calculation of flood control project in Zhongnan Town section of Tianyu River in Zhouzhi County. Shaanxi Water Resources (4), 155–156.Google Scholar
Yoro, SC, Panagiotopoulos, C and Sempéré, R (1999) Dissolved organic carbon contamination induced by filters and storage bottles. Water Research 33(8), 1956–1959.CrossRefGoogle Scholar
Zhang, Y (2008) The response of transport characteristics of riverine organic carbon to regional climate. Earth and Environment 36(4), 348–355.Google Scholar
Zhang, Y (2012) The review of the research of the riverine organic carbon cycle. Journal of Henan Polytechnic University (Natural Science) 31(3), 344–351.Google Scholar
Zhao, G, Pan, B, Li, Y, Zheng, X, Zhu, P, Zhang, L and He, H (2020) Phytoplankton in the heavy sediment-laden Weihe River and its tributaries from the northern foot of the Qinling Mountains: Community structure and environmental drivers. Environmental Science and Pollution Research 27(8), 8359–8370.CrossRefGoogle ScholarPubMed
Zhou, W and Chen, M (2009) Development of radiocarbon dating in China over the past 50 years. Radiocarbon 51(1), 91–107.CrossRefGoogle Scholar
Zhou, W, Lu, X, Wu, Z, Zhao, W, Huang, C, Li, L, Chen, P and Xin, Z (2007) New results on Xi’an-AMS and sample preparation systems at Xi’an-AMS center. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 262(1), 135–142.CrossRefGoogle Scholar
Zigah, PK, McNichol, AP, Xu, L, Johnson, C, Santinelli, C, Karl, DM and Repeta, DJ (2017) Allochthonous sources and dynamic cycling of ocean dissolved organic carbon revealed by carbon isotopes. Geophys Res Lett 44(5), 2407–2415.CrossRefGoogle Scholar
Zigah, PK, Minor, EC and Werne, JP (2012) Radiocarbon and stable-isotope geochemistry of organic and inorganic carbon in Lake Superior. Global Biogeochem Cycles 26(1).CrossRefGoogle Scholar
Zigah, PK, Minor, EC, Werne, JP and McCallister, SL (2011) Radiocarbon and stable carbon isotopic insights into provenance and cycling of carbon in Lake Superior. Limnology and Oceanography 56(3), 867–886.CrossRefGoogle Scholar
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