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Methane Dynamics of Aquaculture Shrimp Ponds in Two Subtropical Estuaries, Southeast China: Dissolved Concentration, Net Sediment Release, and Water Oxidation
Author(s) -
Yang Ping,
Lai Derrick Y. F.,
Yang Hong,
Tong Chuan,
Lebel Louis,
Huang Jiafang,
Xu Jin
Publication year - 2019
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1029/2018jg004794
Subject(s) - estuary , environmental science , biogeochemical cycle , aquaculture , sediment , shrimp , salinity , hydrology (agriculture) , fishery , environmental chemistry , ecology , chemistry , biology , fish <actinopterygii> , geology , paleontology , geotechnical engineering
Aquaculture ponds are potentially large sources of atmospheric methane (CH 4 ) that can exacerbate climate change. A thorough understanding of various CH 4 biogeochemical processes occurring in the ponds is essential for the prediction and management of CH 4 emissions arising from aquaculture. However, the variations in pond CH 4 biogeochemical processes among estuaries and aquaculture stages remain poorly understood. In this study, we assessed the net sediment release, oxidation, and dissolved concentrations of CH 4 in aquaculture ponds in two subtropical estuaries among three shrimp growth stages in Southeast China. Overall, porewater CH 4 concentrations and sediment CH 4 release rates varied greatly among different stages in the order: middle stage > final stage > initial stage. Water column CH 4 concentrations and overlying water CH 4 oxidation rates showed an increasing trend over the study period. Sediment CH 4 release rates and dissolved CH 4 concentrations also varied considerably between the two estuaries. In the more saline Jiulong River Estuary, sediment CH 4 release rate was lower while the shrimp survival rate and yield were higher as compared to the Min River Estuary with a lower water salinity. Our results suggest that both high water salinity and feed utilization efficiency can effectively mitigate CH 4 emissions from the coastal shrimp ponds. Overall, the large magnitude of net CH 4 emissions observed in our shrimp ponds highlights the urgency of formulating appropriate policies and building sustainable institutions that can strike a balance between land‐based aquaculture development and greenhouse gas mitigation in the subtropical coastal regions.