Key Laboratory of Humid Subtropical Eco-geographical Process of Ministry of Education, Fujian Normal University, Fuzhou, 350007, PR China; School of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, PR China; Research Centre of Wetlands in Subtropical Region, Fujian Normal University, Fuzhou, 350007, PR China.
Department of Geography and Resource Management, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
J Environ Manage. 2019 Apr 15;236:224-235. doi: 10.1016/j.jenvman.2019.01.088. Epub 2019 Feb 5.
Aquaculture ponds can emit a large amount carbon dioxide (CO), with the consequence of exacerbating global climate change. Many studies about CO dynamics across the water-air interface, but CO in sediment and overlying water received relative less attention. In this study, CO concentration in sediment porewater, the diffusive CO fluxes across the sediment-water interface (SWI), and the CO production rates in the overlying water (CO) were determined in the shrimp ponds in the Min River Estuary (MRE) and Jiulong River Estuary (JRE), southeast China, to analyze the dynamics of CO among different growth stages of shrimps. Our results showed large variations in porewater CO concentrations, CO diffusive fluxes and CO rates among different growth stages, with markedly larger values in the middle stage of shrimp growth. The temporal variation of CO in both estuarine ponds followed closely the seasonal change of temperature. The internal CO production (CO) in these ponds was dominated by sediments. A significantly larger mean porewater CO concentrations, diffusive fluxes and production rate were observed in the MRE ponds than those in the JRE ponds, which could be attributed to the lower water salinity and a larger source of carbon substrates in the former estuary. Considering a total surface area of 6.63 × 10 km across the mariculture ponds in subtropical estuaries, it is estimated conservatively that approximately 100 Gigagram (Gg) of dissolved organic carbon and 190 Gg of dissolved inorganic carbon were transported annually from the mariculture ponds into China's coastal areas. Because of the substantial supply of dissolved carbon, the adjacent coastal waters receiving effluent discharge from the mariculture ponds could become "hotspots" of CO emissions. Our results highlight the role of aquaculture pond as a major CO source in China's coastal areas, and effective actions are needed to alleviate the greenhouse gas (GHG) emissions from these ponds.
水产养殖池塘会排放大量二氧化碳（CO），从而加剧全球气候变化。许多研究都涉及水体-空气界面的 CO 动态，但对沉积物和上覆水中的 CO 关注相对较少。本研究测定了中国东南闽江河口和九龙江河口虾塘沉积物孔隙水中的 CO 浓度、通过沉积物-水界面（SWI）的 CO 扩散通量以及上覆水中的 CO 生成速率，以分析虾不同生长阶段 CO 在不同相之间的动态变化。结果表明，不同生长阶段的孔隙水 CO 浓度、CO 扩散通量和 CO 生成速率差异较大，虾生长中期的数值明显较大。两个河口池塘中 CO 的时间变化与温度的季节性变化密切相关。这些池塘的内部 CO 生成（CO）主要来自沉积物。与九龙江河口池塘相比，闽江河口池塘的孔隙水 CO 浓度、扩散通量和生成速率的平均值均较大，这可能归因于前者的低盐度和更大的碳底物来源。考虑到亚热带河口养殖池塘的总面积为 6.63×104km2，保守估计每年有大约 100 吉克（Gg）溶解有机碳和 190 Gg 溶解无机碳从养殖池塘输送到中国沿海地区。由于溶解碳的大量供应，从养殖池塘排放污水的邻近沿海水域可能成为 CO 排放的“热点”。本研究结果强调了水产养殖池塘作为中国沿海地区主要 CO 源的作用，需要采取有效措施缓解这些池塘的温室气体（GHG）排放。
