天气状况对富营养化池塘水-气界面冬季二氧化碳通量的影响

Influence of Weather Condition on CO_2 Flux in Eutrophic Pond Water-Air Interface in Winter

为揭示富营养化浅水池塘冬季不同天气状况的昼夜性温室气体通量特征,利用静态浮箱法连续7d监测了宜昌市富营养化池塘冬季水-气界面昼夜性CO_2通量,7d内的天气状况各异,包括晴天、阴天和雨天,能较好的代表冬季池塘通量特征.观测点在7d内的平均CO_2通量为7.09mg·m^(-2)·h^(-1);单日CO_2通量最大为11.26mg·m^(-2)·h^(-1),最小为-3.20mg·m^(-2)·h^(-1).阴雨天CO_2的排放通量为9.76mg·m^(-2)·h^(-1),约是晴天的两倍,且全天CO_2均呈向大气排放状态.晴天时CO_2通量在冬季表现为极弱的排放,3d平均通量约为3.76mg·m^(-2)·h^(-1),白天水体表现为CO_2的汇.在观测期间内CO_2扩散通量昼夜性变化明显,晴天时扩散通量与水温、叶绿素、溶解氧、pH呈显著负相关,与气压呈正相关,水体中的藻类等浮游植物在晴天的光合作用强度大于呼吸作用,导致在白天(10:00~18:00)池塘表现为吸收大气中的CO_2.阴雨天气通量与气温、水温呈负相关,与溶解氧、叶绿素、风速、气压呈显著正相关.不同的天气状况下环境因子昼夜性变化,导致了气体通量的昼夜性变化特征.

Carbon dioxide（CO2）emission pathways in winter have been quantified during a 7 days online survey of a eutrophic shallow pond in Yichang,China.The weather conditions are different in 7 days,including sunny,cloudy and raainy days,which can better represent the characteristics of the winter pond flux.The total average emission flux of CO2 was 7.09 mg·m^-2·h^-1;the maximum CO2 flux was 11.26 mg·m^-2·h^-1;and the maximum CO2 flux was -3.20 mg·m^-2·h^-1 in monitoring period.The emission flux of CO2 in the cloudy day was 9.76 mg·m^-2·h^-1,is about two times of the sunny day;and water was a strong source of atmospheric carbon dioxide.The total emission fluxes of CO2 remains at a very low level and the average value were 3.76 mg·m^-2·h^-1.The diffusion flux was negatively correlated with water temperature,chlorophyll,dissolved oxygen（DO）and pH in clear day,and was positively correlated with air pressure.In the cloudy and rainy weather,the flux is negatively correlated with the temperature and water temperature,and has a significant positive correlation with the DO,chlorophyll,wind speed and air pressure.The day and night-changes of environmental factors caused by different weathers and times resulted in the day and night variation of gas flux.