Contrasting methane emissions from upstream and downstream rivers and their associated subtropical reservoir in eastern China

• Published in: Scientific reports Vol. 9; no. 1; p. 8072
• Main Author: Yang, Le
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 30-05-2019; Nature Publishing Group; Nature Portfolio
• Subjects: 692/499; 704/106; 704/106/47; Downstream; Emissions; Greenhouse gases; Humanities and Social Sciences; Methane; multidisciplinary; Reservoirs; Rivers; Science; Science (multidisciplinary); Seasonal variations; Stream discharge; Stream flow; Upstream; Water inflow; China
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-019-44470-2

Subtropical reservoirs are an important source of atmospheric methane (CH
4
). This study investigated the spatiotemporal variability of bubble and diffusive CH
4
emissions from a subtropical reservoir, including its upstream and downstream rivers, in eastern China. There was no obvious seasonal variation in CH
4
emissions from the main reservoir, which increased slightly from the first half year to the next half year. In the upstream river, CH
4
emissions were low from February to June and fluctuated widely from July to January due to bubble activity. In the downstream river, CH
4
emissions were lowest in February, which was possibly influenced by the low streamflow rate from the reservoir (275 m
3
s
−1
) and a short period of mixing. There was spatial variability in CH
4
emissions, where fluxes were highest from the upstream river (3.65 ± 3.24 mg CH
4
m
−2
h
−1
) and lowest from the main reservoir (0.082 ± 0.061 mg CH
4
m
−2
h
−1
), and emissions from the downstream river were 0.49 ± 0.20 mg CH
4
m
−2
h
−1
. Inflow rivers are hot spots in bubble CH
4
emissions that should be examined using field-sampling strategies. This study will improve the accuracy of current and future estimations of CH
4
emissions from hydroelectric systems and will help guide mitigation strategies for greenhouse gas emissions.