基于TBL模型的闽江口围垦养虾塘水-大气界面CO_2扩散通量估算

Diffusive CO_2 Flux Across the Water-air Interface of Reclaimed Shrimp Ponds in the Minjiang River Estuary Based on the TBL Model

扩散模型是估算水生生态系统水-大气界面二氧化碳(CO_2)交换通量的重要手段.选取多种参数化方法对闽江口围垦养虾塘水-大气界面CO_2气体交换速率(k_x)及CO_2扩散通量进行估算,探讨闽江口围垦养虾塘k_x及CO_2扩散通量的变化特征及影响因素.结果表明:①养殖期水-大气界面CO_2气体交换速率及其扩散通量均呈现显著的时间变化特征,分别表现为10月> 9月> 11月> 7月> 8月和11月> 7月> 8月> 9月> 10月的变化趋势;②风速、pH、水体CO_2、DOC和叶绿素a(Chl-a)浓度是影响CO_2扩散通量时间变化特征的重要因素;③不同参数化方法计算得出的闽江口养虾塘水-大气界面CO_2扩散通量存在显著差异(P <0. 01),表明模型方法估算养殖塘CO_2扩散通量具有一定不确定性,综合分析认为模型RC01和CW03是估算闽江口围垦养虾塘水-大气界面CO_2扩散通量较为合适的方法.

Freshwater aquatic ecosystems are important sources of greenhouse gases,such as CO2.However,few studies have presented data on the greenhouse gas flux from coastal aquaculture ponds.Diffusion models are important tools for estimating the CO2 exchange flux across the water-air interface of aquatic ecosystems.Several different parameterized means were selected to estimate the CO2 gas exchange rate(kx)and CO2 diffusive flux across the water-air interface of shrimp ponds in the Minjiang River Estuary.The results indicated that:①the CO2 gas exchange rate and diffusive flux over the culture period all presented significant temporal variation.This variation showed a dynamic trend:October>September>November>July>August and November>July>August>September>October.②Wind speed,kx,CO2 concentration,pH,DOC concentration,and Chl-a concentration were important factors affecting the temporal variation of CO2 diffusive flux.③There were differences in the estimated value of CO2 diffusive flux across the water-air interface of the culture ponds in the Minjiang River Estuary among different parameterized approaches(P<0.01).This indicates that the model method has some uncertainties in estimating the CO2 diffusive flux in culture ponds.Our results suggest that the models RC01 and CW03 are more suitable methods for estimating the CO2 diffusive flux at the water-air interface of estuarine reclaimed aquaculture ponds in the Minjiang River Estuary,after comprehensive analysis of the water environment and the different estimation results.