the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Methane emissions from a sediment-deposited island in a Lancang-Mekong reservoir
Abstract. In dammed rivers, sediment accumulation creates potential methane emission hotspots, which have been extensively studied in forebays. However, methane emissions from sidebays remain poorly understood. We investigated methane emissions from a sediment-deposited island situated in the sidebay of the Manwan Reservoir, Lancang-Mekong River. High methane emissions (maximum 10.4 mg h−1 m−2) were observed at the island center, while a ring-like zone of low-to-negative methane emission was discovered around the island edge, whose flux varied between −0.2–1.6 mg h−1 m−2. The ring-like zone accounted for 89.1 % of the island area, of which 9.1 % was a methane sink zone. Microbial processes in the hyporheic zone, regulated by hydrological variations, were responsible for the low methane flux in this area. Under reservoir operation, frequent water level fluctuations enhanced hyporheic exchange and created redox gradients along the hyporheic flow path. Dissolved oxygen in hyporheic water decreased from 4.80 mg L−1 at the island bank edge to 0.43 mg L−1 at the center, which in turn decreased methanogen abundance for methane production and increased methanotroph abundance for methane oxidation at the ring-like zone. This study adds to our understanding of methane emissions from dammed rivers and helps to screen efficient strategies for future mitigation of the global warming effects of hydropower systems.
This preprint has been withdrawn.
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This preprint has been withdrawn.
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Preprint
(1051 KB)
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Supplement
(454 KB)
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This preprint has been withdrawn.
- Preprint
(1051 KB) - Metadata XML
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Supplement
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Interactive discussion
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RC1: 'reviewer comment', Anonymous Referee #1, 31 Oct 2018
- AC1: 'Author's Response to Comments from Referee #1', Qiuwen Chen, 20 Nov 2018
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RC2: 'Comments to the Authors', Anonymous Referee #2, 01 Nov 2018
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AC2: 'Author's Response to Comments from Referee #2', Qiuwen Chen, 20 Nov 2018
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EC1: 'Technical correction required prior to the editor decision', Ji-Hyung Park, 23 Nov 2018
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AC3: 'Author's Response to Comments from Editor', Qiuwen Chen, 24 Nov 2018
- AC4: 'Author's Response to Comments from Editor', Qiuwen Chen, 17 Dec 2018
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AC3: 'Author's Response to Comments from Editor', Qiuwen Chen, 24 Nov 2018
-
EC1: 'Technical correction required prior to the editor decision', Ji-Hyung Park, 23 Nov 2018
-
AC2: 'Author's Response to Comments from Referee #2', Qiuwen Chen, 20 Nov 2018
Interactive discussion
-
RC1: 'reviewer comment', Anonymous Referee #1, 31 Oct 2018
- AC1: 'Author's Response to Comments from Referee #1', Qiuwen Chen, 20 Nov 2018
-
RC2: 'Comments to the Authors', Anonymous Referee #2, 01 Nov 2018
-
AC2: 'Author's Response to Comments from Referee #2', Qiuwen Chen, 20 Nov 2018
-
EC1: 'Technical correction required prior to the editor decision', Ji-Hyung Park, 23 Nov 2018
-
AC3: 'Author's Response to Comments from Editor', Qiuwen Chen, 24 Nov 2018
- AC4: 'Author's Response to Comments from Editor', Qiuwen Chen, 17 Dec 2018
-
AC3: 'Author's Response to Comments from Editor', Qiuwen Chen, 24 Nov 2018
-
EC1: 'Technical correction required prior to the editor decision', Ji-Hyung Park, 23 Nov 2018
-
AC2: 'Author's Response to Comments from Referee #2', Qiuwen Chen, 20 Nov 2018
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Wenqing Shi
Qiuwen Chen
Jianyun Zhang
Cheng Chen
Yuchen Chen
Yuyu Ji
Juhua Yu
Bryce R. Van Dam
This preprint has been withdrawn.
- Preprint
(1051 KB) - Metadata XML
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Supplement
(454 KB) - BibTeX
- EndNote