典型湿地环境条件下Shewanella介导N2O产生机制及意义

Mechanism and Significance of Shewanella Mediated N2O Emission under Simulated Typical Wetland Conditions

利用湿地中高丰度的代表性反硝化菌Shewanella denitrificans,文章通过批式实验,探究典型湿地环境条件下pH和C/N对微生物反硝化排放N2O的影响和机制。结果表明,在典型湿地环境条件下,S.denitrificans介导的反硝化均能排放N2O温室气体。其中,当C/N为7.5或75时N2O排放速率最快,比最低排放速率高出约54%。当pH为5.5时,N2O排放速率较pH为6.5时增加约67%。不同pH和C/N条件下N2O的排放差异可能主要由p H差异导致,或p H和C/N差异共同所致。双因素方差分析结果表明,pH和C/N不仅分别显著影响N2O排放,并且两者对N2O排放具有显著的交互影响。这些发现为湿地生态系统N2O排放的模型构建和评估预测提供了科学依据。

Shewanella denitrificans,a highly abundant representative denitrifier in wetland,was used to investigate the impact and mechanism of pH and C/N on denitrification-derived N2O emission via batch experiments under simulated typical wetland conditions.The experimental results showed that S.denitrificans-mediated denitrification can release N2O under all the simulated wetland conditions.The highest N2O emission rate was observed under conditions with C/N 7.5 or 75,which was 54%higher than the lowest emission rate.When the pH decreased from 6.5 to 5.5,not only the amount of N2O emission increased,but also the N2O emission rate accelerated,and the emission rate can increase by 67%.The difference in N2O emissions under simulated typical p H and C/N conditions could be mainly controlled by the pH difference,or jointly controlled by pH and C/N differences.Two-way analysis of variance showed that both pH and C/N significantly affected the N2O emission rate,and they also had a significant interaction effect on N2O emission.These findings provided a scientific basis for modelling and prediction of N2O emission from wetland ecosystems.