Cascading multiscale watershed effects on differential carbon isotopic characteristics and associated hydrological processes

JOURNAL OF HYDROLOGY

卷:588

Article

Gao, Yang^1,3  Jia, Junjie^1,3  Lu, Yao^1,3  Zhou, Feng⁴  Hao, Zhuo^1,3  Johnes, Penny J.⁵  Dungait, Jennifer A. J.⁶  Shi, Kun² 

[1] Chinese Acad Sci, Key Lab Ecosyst Network Observat & Modeling, Inst Geog Sci & Nat Resources Res, Beijing 100101, Peoples R China

[2] Chinese Acad Sci, State Key Lab Lake Sci & Environm, Nanjing Inst Geog & Limnol, Nanjing 210008, Peoples R China

[3] Univ Chinese Acad Sci, Beijing 100049, Peoples R China

[4] Peking Univ, Coll Urban & Environm Sci, Sinofrench Inst Earth Syst Sci, Beijing, Peoples R China

[5] Univ Bristol, Sch Geog Sci, Univ Rd, Bristol BS8 1SS, Avon, England

[6] Univ Exeter, Geog, CLES, Amory Bldg,Rennes Dr, Exeter EX4 4RJ, Devon, England

关键词: C transport;    C-13;    Watershed;    Scale effect;    Hydrological process;   

DOI  :  10.1016/j.jhydrol.2020.125139

来源: Elsevier

【 摘 要 】

Understanding land-use change accompanied by anthropogenic activities under alterations in watershed size regulations or differential carbon (C) isotope characteristics remain a challenge in C cycling research. In this study, we investigate changes in the export of C composition and its isotopic characteristics at multiple scales in a subtropical cascading watershed in China. Results show that C concentrations in rainfall and dissolved total carbon (DTC), dissolved organic carbon (DOC) and delta C-13 in runoff seasonally fluctuate at a temporal scale. On average, the delta C-13 from silicate rock weathering was 31-32%, contributing the largest amount of delta C-13 in the different watersheds. Moreover, the contribution of isotopic composition from atmospheric deposition to the delta C-13 fraction increased as watershed size increased, while the corresponding contribution from soil organic matter (SOM) decomposition decreased. On the other hand, anthropogenic activities play a dominant role in the isotopic composition of large watersheds. In addition, the correlation coefficient between C transport via runoff and the delta O-18 value in rainfall increased as watershed size increased. This indicated that as a source rainfall had an obvious influence on C transport in runoff according to proportional values measured in event and pre-event water.

【 授权许可】

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