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Fabre C, Wei X, Sauvage S, Le TPQ, Ouillon S, Orange D, Herrmann M, Sánchez-Pérez JM. Assessing fluvial organic carbon flux and its response to short climate variability and damming on a large-scale tropical Asian river basin. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 903:166589. [PMID: 37634727 DOI: 10.1016/j.scitotenv.2023.166589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 08/24/2023] [Accepted: 08/24/2023] [Indexed: 08/29/2023]
Abstract
Fluvial organic carbon (OC) transfer is an essential resource for downstream ecosystems. Multiple factors affect its transfer process, e.g., climate or anthropogenic activities. Quantifying OC fluxes with fine spatiotemporal resolution is challenging in anthropised catchments. This study aims to quantify daily OC dynamics and to assess the impacts of short climate variability and damming on OC spatiotemporal transfer processes in a large tropical Asian river basin (the Red River) for an extended period (2003-2013) by combining empirical equations with modelling outputs. Firstly, empirical equations for calculating dissolved (DOC) and particulate OC (POC) concentrations were calibrated based on in-situ sampling data. Then, simulated daily discharge (Q) and suspended sediment concentrations were used to quantify daily OC fluxes. Results show that the parameters of the DOC and POC equations well represent the subbasins characteristics, underlining the effects of soil OC content, mean annual Q and Chlorophyll a. DOC and POC exports reached 222 and 406 kt yr-1 at the basin outlet, accounting for 0.38 % of the total OC (TOC) exported by Asian rivers to the ocean. However, the specific yields of DOC (1.62 t km-2 yr-1) and POC (2.96 t km-2 yr-1) of the Red River basin were ~ 1.5 times those of other Asian basins. By comparing a reference scenario (without dams) to current conditions, we estimated 12 % and 88 % decreases in DOC and POC fluxes between 2008-2013 and 2003-2007, mainly due to damming. This study shows that climate variability may not impact OC dynamics in rivers as it explained <2 % of the variations. However, dam management, especially recent ones operating since 2008, deeply influences OC variations as the POC/TOC ratio decreased from 86 % to 47 %. Damming significantly decreased POC exports due to sediment retention, altering the equilibrium of OC cycling downstream, which may impact the food chain.
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Affiliation(s)
- Clément Fabre
- Laboratoire Ecologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, INPT, UPS, Avenue de l'Agrobiopole, 31326 Auzeville-Tolosane, France
| | - Xi Wei
- Laboratoire Ecologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, INPT, UPS, Avenue de l'Agrobiopole, 31326 Auzeville-Tolosane, France
| | - Sabine Sauvage
- Laboratoire Ecologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, INPT, UPS, Avenue de l'Agrobiopole, 31326 Auzeville-Tolosane, France.
| | - Thi Phuong Quynh Le
- Institute of Natural Product Chemistry (INPC), Vietnam Academy of Science and Technology (VAST), 100000 Hanoi, Viet Nam
| | - Sylvain Ouillon
- LEGOS, Université de Toulouse, IRD, CNES, CNRS, UPS, 31400 Toulouse, France; USTH, Vietnam Academy of Science and Technology (VAST), 100000 Hanoi, Viet Nam
| | - Didier Orange
- HydroSciences Montpellier, Université de Montpellier, CNRS, IMT, IRD, 34095 Montpellier, France
| | - Marine Herrmann
- LEGOS, Université de Toulouse, IRD, CNES, CNRS, UPS, 31400 Toulouse, France; USTH, Vietnam Academy of Science and Technology (VAST), 100000 Hanoi, Viet Nam
| | - José-Miguel Sánchez-Pérez
- Laboratoire Ecologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, INPT, UPS, Avenue de l'Agrobiopole, 31326 Auzeville-Tolosane, France
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Dissolved Organic Carbon Flux Is Driven by Plant Traits More Than Climate across Global Forest Types. FORESTS 2022. [DOI: 10.3390/f13071119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Dissolved organic carbon (DOC) is one of the most important components in the global carbon cycle, which is largely influenced by climate and plant traits. Although previous studies have examined the impacts of climatic factors (e.g., mean annual temperature (MAT) and precipitation (MAP)) or plant traits (e.g., leaf area index, leaf nitrogen) on DOC, the relative importance of climate and plant traits on DOC flux remains unclear on a global scale. In this study, we compiled 153 pairs of DOC observational data from 84 forest sites to explore the relative importance of climate and plant traits on DOC flux with a linear mixed model, variance partitioning, and random forest approaches. Our results showed that DOC fluxes from throughfall and the litter layer were higher in broadleaved forests than those in coniferous forests. Throughfall-DOC flux increased significantly with MAT and MAP in coniferous forests, but that from the litter layer showed no significant correlations with climate factors. In broadleaved forests, throughfall-DOC flux increased with potential evapotranspiration (PET), while that from the litter layer was positively correlated with MAT. Meanwhile, throughfall-DOC flux had negative relationships with specific leaf area (SLA), leaf nitrogen content (LN), and leaf phosphorus content (LP) in broadleaved forests, but it showed a positive correlation with SLA in coniferous forests. Litter-layer-DOC flux increased with LN in broadleaved forests, but this correlation was the opposite in coniferous forests. Using the variance partitioning approach, plant traits contributed to 29.0% and 76.4% of the variation of DOC from throughfall and litter layer, respectively, whereas climate only explained 19.1% and 8.3%, respectively. These results indicate that there is a more important contribution by plant traits than by climate in driving the spatial variability of global forest DOC flux, which may help enhance forest management as a terrestrial carbon sink in the future. Our findings suggest the necessity of incorporating plant traits into land surface models for improving predictions regarding the forest carbon cycle.
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Wang S, Li H, Wei X, Zhu N, Sun P, Xia L, Tang C, Han Q, Zhang G, Liu C, Wang X, Dolfing J, Wu Y, Peñuelas J, Zhu YG. Dam Construction as an Important Anthropogenic Activity Disturbing Soil Organic Carbon in Affected Watersheds. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:7932-7941. [PMID: 32501717 DOI: 10.1021/acs.est.9b06304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
To explore whether and how anthropogenic activities related to surface water regulation (i.e., dam construction) disturb soil ecosystems in the surrounding uplands, a long-term monitoring program was conducted from 1998 to 2017 in the Three Gorges Reservoir Region, China. The Three Gorges Dam (TGD) is the largest hydraulic engineering project in the world. We present a direct, ecosystem-scale demonstration of changes in the soil organic carbon (SOC) content in the TGD watershed before and after the surface water was reshaped. The average SOC content decreased from 12.9 to 9.5 g/kg between 2004 and 2012 and then recovered to 13.8 g/kg in 2017. Dynamics of SOC were partly attributed to shifts in the composition of soil microbial communities responsible for carbon biogeochemistry. The shifts in microbial taxa were associated with the changed microclimate affected by the TGD as well as global and regional climate variability. The microclimate, soil microorganisms, and plant organic carbon input explained 40.2% of the variation in the SOC content. This study revealed that dam construction was an important and indirect driver for the SOC turnover, and the subsequent effects on the upland soil ecosystem must be considered when large-scale disturbance activities (such as dam construction) are conducted in the future.
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Affiliation(s)
- Sichu Wang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008, China
- Zigui Three Gorges Reservoir Ecosystem, Observation and Research Station of Ministry of Water Resources of the People's Republic of China, Shuitianba Zigui, Yichang 443605, China
- College of Advanced Agricultural Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hongying Li
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008, China
- Zigui Three Gorges Reservoir Ecosystem, Observation and Research Station of Ministry of Water Resources of the People's Republic of China, Shuitianba Zigui, Yichang 443605, China
- College of Resource and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaorong Wei
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Ningyuan Zhu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008, China
- Zigui Three Gorges Reservoir Ecosystem, Observation and Research Station of Ministry of Water Resources of the People's Republic of China, Shuitianba Zigui, Yichang 443605, China
| | - Pengfei Sun
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008, China
- Zigui Three Gorges Reservoir Ecosystem, Observation and Research Station of Ministry of Water Resources of the People's Republic of China, Shuitianba Zigui, Yichang 443605, China
| | - Lizhong Xia
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008, China
- Zigui Three Gorges Reservoir Ecosystem, Observation and Research Station of Ministry of Water Resources of the People's Republic of China, Shuitianba Zigui, Yichang 443605, China
| | - Cilai Tang
- College of Hydraulic & Environmental Engineering, China Three Gorges University, Yichang 443002, Hubei, China
| | - Qingzhong Han
- Zigui Center of Agricultural Technology Extension, Danyang Road, Zigui, Yichang 443600, Hubei, China
| | - Guangguo Zhang
- Zigui Center of Agricultural Technology Extension, Danyang Road, Zigui, Yichang 443600, Hubei, China
| | - Chiju Liu
- Zigui Meteorological Bureau, 1, Tianwen Road, Zigui, Yichang 443600, Hubei, China
| | - Xuefeng Wang
- Zigui Meteorological Bureau, 1, Tianwen Road, Zigui, Yichang 443600, Hubei, China
| | - Jan Dolfing
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - Yonghong Wu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008, China
- Zigui Three Gorges Reservoir Ecosystem, Observation and Research Station of Ministry of Water Resources of the People's Republic of China, Shuitianba Zigui, Yichang 443605, China
- College of Hydraulic & Environmental Engineering, China Three Gorges University, Yichang 443002, Hubei, China
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - Josep Peñuelas
- Consejo Superior de Investigaciones Cientı́ficas (CSIC), Global Ecology Unit, Centre for Ecological Research and Forestry Applications (CREAF)-CSIC, Universitat Autonoma de Barcelona (UAB), Bellaterra, Barcelona 08193, Catalonia, Spain
| | - Yong-Guan Zhu
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
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