亚热带河口陆基养殖塘底泥甲烷产生动力学研究

河口区陆基围垦养殖塘是重要的温室气体排放源，但其底泥甲烷产生动力学特征目前尚未厘清.本研究对我国东南沿海亚热带闽江河口、木兰溪河口和九龙江河口的6个南美白对虾（Penaeus vannamei）养殖塘底泥进行了为期60 d的室内厌氧培养，并对甲烷累积产量曲线利用一阶动力学模型及改进的岡珀茨模型进行拟合和分析.结果表明，所有河口陆基养殖塘底泥产甲烷过程是一个动态变化过程，可分为延滞、产生和稳定3个阶段.延滞期发生在培养初期1~4 d，产生期主要集中在4~25 d，在培养25 d后，所有养殖塘底泥的甲烷累积产量曲线趋于平衡.盐度和孔隙水DOC浓度均能够影响养殖塘底泥甲烷产生动力学拟合参数.随着养殖塘底泥盐度的增加，甲烷最大产生潜力由5961 ng·g^-1减少至559 ng·g^-1，甲烷最大产生速率由674 ng·g^-1·d^-1减少至84 ng·g^-1·d^-1.研究表明，一阶动力学模型更适合低盐养殖塘底泥甲烷产生动力学过程的拟合，而改进的岡珀茨模型更适合高盐养殖塘底泥甲烷产生动力学过程的拟合.选择近海养殖塘进行南美白对虾养殖及在甲烷产生期来临之前清除底泥可极大程度地减少养殖塘底泥温室气体CH₄的产生潜力.

Kinetics of methane production from the sludge of wetland-based reclaimed shrimp pools in the subtropical estuaries

Wetland-based reclaimed aquaculture pools play an important role in offsetting carbonaceous greenhouse gas emissions in coastal areas. However, the kinetic characteristics of the potential methane production of these aquaculture pools have not been clarified yet. Herein, we investigated six shrimp (Penaeus vannamei) pools in subtropical estuaries (Min river, Mulan river and Jiulong river) in southeast China. By applying the first-order kinetic model and the modified Gompertz model, the potential methane production of the sludge of these pools was anaerobically incubated for 60 days. All the processes of potential methane production can be divided into three stages:lag phase, production phase and stability phase. The lag phase occurred in the first 1~4 days, and the production period was mainly concentrated in 4~25 days. After 25 days, the methane accumulation curves in the shrimp pools'' sludge tended to be stable. Salinity and DOC, both can affect the kinetic fitting parameters of methane production. With an increase in salinity, the potential methane production decreased from 5961 ng·g^-1 to 559 ng·g^-1, and the maximum methane production rates decreased from 674 ng·g^-1·d^-1 to 84 ng·g^-1·d^-1. Our results suggested that the first-order kinetic model and the modified Gompertz model are best fitted to the methane production process in low- and high-salt shrimp pools, respectively. Offshore shrimp aquaculture and the disposal of pool bottom sludge may greatly reduce greenhouse gas emissions.