| 三峡水库支流甲烷排放研究进展 |
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| 引用本文： | 毛羽丰,何蕊序,李宏,杨胜发,余薇薇,叶开来,林彤,白小霞,何强.三峡水库支流甲烷排放研究进展[J].湖泊科学,2024,36(1):17-33. |
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| 作者姓名： | 毛羽丰 何蕊序 李宏 杨胜发 余薇薇 叶开来 林彤 白小霞 何强 |
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| 作者单位： | 重庆交通大学, 国家内河航道整治工程技术研究中心, 重庆 400074;重庆交通大学, 水利水运工程教育部重点实验室, 重庆 400074;重庆大学, 三峡库区生态环境教育部重点实验室, 重庆 400045 |
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| 基金项目： | 国家自然科学基金项目(52270196,U20A20326,52000018)、重庆市自然科学基金项目(cstc2020jcyj-msxmX0176)、重庆市教育委员会科学技术项目(KJQN202000745)、中国科协青年人才托举工程项目(2022QNRC001)和水利水运工程教育部重点实验室开放基金项目(SLK2021B06)联合资助。 |
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| 摘 要： | 甲烷(CH4)对全球温室效应有着较大的贡献。三峡水库自2003年蓄水以来,其CH4排放问题已受到广泛关注。但三峡水库反季节的运行方式,使支流库湾CH4的产生和传输过程受到多方面的影响,进而导致其CH4排放效应尚不十分明确。本文综述了三峡水库支流CH4排放的研究进展,典型支流的CH4排放通量普遍高于干流,位于三峡水库库尾的部分支流CH4排放通量高于三峡水库库首及库中支流。大多数典型支流的CH4通量在夏季均达到全年峰值,而在冬季高水位运行期均处于相对较低的水平。同时本文主要从水环境条件、水动力条件、人类活动及气象条件4个方面阐述了三峡水库支流CH4排放的影响因素。1)水环境条件:支流水华后藻类衰亡分解过程会驱动CH4释放,且藻类的演替过程会加剧CH4的产生;温度可以直接影响CH4的生成速率和消耗速率,也能通过促进藻的生长间接影响CH4排放;支流相对较低的甲烷氧化菌丰度是其CH4通量较高的原因之一。2)水动力条件:蓄水期CH4主要以扩散的方式进行释放,支流较低的流速促进了悬浮物的沉积,上游沉积物中的CH4含量高于下游;泄水期CH4主要以冒泡的方式进行释放,下游沉积物中TOC急剧增加,但干流的入侵会削弱支流的温度分层,破坏藻类生长环境,间接影响CH4通量。3)人类活动:农业耕作使支流水体中的营养物浓度增加,甲烷氧化菌的丰富度降低,细菌群落的营养相关代谢增强;建设用地扩大、支流筑坝增加抑制了有机物的传输,增加了水体中的产CH4底物,促进了CH4的产生。4)气象条件:降雨会携带更多营养物质进入支流,同时会增加水体浊度、破坏水体的温度分层,从而对CH4的产生和传输过程造成影响。最后对未来的研究热点进行了展望,以期为三峡水库CH4排放的控制和管理提供参考。
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| 关 键 词： | 三峡水库 支流 甲烷排放 水环境条件 水动力条件 人类活动 气象条件 |
| 收稿时间： | 2023/4/5 0:00:00 |
| 修稿时间： | 2023/7/4 0:00:00 |
Research progress on methane emissions from tributaries of the Three Gorges Reservoir |
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| Mao Yufeng,He Ruixu,Li Hong,Yang Shengf,Yu Weiwei,Ye Kailai,Lin Tong,Bai Xiaoxi,He Qiang.Research progress on methane emissions from tributaries of the Three Gorges Reservoir[J].Journal of Lake Science,2024,36(1):17-33. |
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| Authors: | Mao Yufeng He Ruixu Li Hong Yang Shengf Yu Weiwei Ye Kailai Lin Tong Bai Xiaoxi He Qiang |
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| Institution: | National Engineering Research Center for Inland Waterway Regulation, Chongqing Jiaotong University, Chongqing 400074, P.R. China;Key Laboratory of Hydraulic and Waterway Engineering of the Ministry of Education, Chongqing Jiaotong University, Chongqing 400074, P.R. China;Key Laboratory of the Three Gorges Reservoir Region''s Eco-Environment, State Ministry of Education, Chongqing University, Chongqing 400045, P.R. China |
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| Abstract: | Methane (CH4) has a large contribution to the global greenhouse effect. The CH4 emission from the Three Gorges Reservoir has attracted considerable attention since its impoundment in 2003. However, the unique operation mode of the Three Gorges Reservoir affected the CH4 emission and transport in its tributaries. However, the underlying mechanism of CH4 emissions remains unclear. This study reviewed the research progress of CH4 emission from the tributaries of the Three Gorges Reservoir. The CH4 fluxes of typical tributaries were generally higher than those of the main streams. The CH4 emission flux of some tail tributaries of the Three Gorges Reservoir was higher than that of the head and tributaries. The CH4 fluxes in most typical tributaries have peak values in summer, and relatively low values during high water operation in winter. The factors influencing CH4 emission from these tributaries mainly included algae, climatic factors, hydrodynamic conditions and human activities. The future research hotspots were summarized. 1) Algae: The impoundment of the Three Gorges Reservoir has led to intensified algal blooms in some of its tributaries. The dominant species of phytoplankton gradually changed from river-type algae to lake-type algae in the early stage of water storage. This succession of phytoplankton would increase CH4 production. In addition, the algal bloom in tributaries of the Three Gorges Reservoir, would undergo seasonal succession. Phytoplankton dominated by green algae and cyanobacteria has high contribution to CH4 emission. 2) Climatic factors: The generation and consumption rate of tributary CH4 were positively correlated with temperature. In general, higher temperature promote the growth of algae. However, the out-of-season scheduling mode of the Three Gorges Reservoir also enhances phytoplankton production in winter. The tributary temperature stratification would further aggravate algal bloom, providing substrate for CH4 production. Rainfall affected CH4 discharge of these tributaries by increasing the content of organic matter, the abundance of methanogenic bacteria, and disturbing the surface water. The degree of impact was related to the magnitude of rainfall runoff. 3) Hydraulic conditions: During the low water level period of the Three Gorges Reservoir, CH4 consumption in the water body was lower enhancing CH4 transmission. Moreover, the water level change caused by the operation of the reservoir also affects environmental factors such as temperature stratification, algae growth and organic matter distribution, which has an indirect impact on the CH4 flux of tributaries. 4) Human activities: Land use changes caused by human activities would increase nutrient concentrations in tributary water bodies and enhance nutrient-related metabolism of bacterial communities, resulting in an increase of CH4 emission. The damming and reservoir operation in the tributary area changed the hydrodynamic conditions of the tributary, blocked the transport of organic matter, and thus increased the total organic carbon content in the sediment, providing more substrate for CH4 production. Finally, the future research hotspots were summarized to provide scientific basic for the management of CH4 emissions in the Three Gorges Reservoir. |
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| Keywords: | Three Gorges Reservoir tributaries methane emission water environmental conditions hydrodynamic conditions human activities meteorological conditions |
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