生物炭添加对人工湿地氨气排放的影响研究——基于微生物群落组装机制分析

Study on the effect of biochar addition on ammonia emission from constructed wetlands--Based on the analysis of microbial community assembly mechanism

基于中宇宙模拟实验,探究了不同生物炭添加比例对表流人工湿地脱氮性能及氨气减排效果的影响及作用机理,并通过机器学习和基于系统发育分箱的零模型(iCAMP)进一步探讨了其中的微生物学机制.结果表明,与未添加生物炭的对照组相比,添加50%的生物炭显著促进了人工湿地中氨氧化菌(如Chloroflexi、Rhodocyclaceae)的生长,增强了系统内氨氮的转化,减少了32%的氨气排放量.随机森林模型筛选得到的敏感微生物物种(如Planctomycetes、Parcubacteria)可作为指示氨挥发排放通量的初步指标.人工湿地基质中生物炭的比例与群落结构的变化存在密切联系.生物炭添加比例的升高导致物种系统发育结构聚集并促进了与碳、氮循环相关的特定功能细菌群落(如Gammaproteobacteria、Deltaproteobacteria)的生长和建立.本研究为揭示控制人工湿地微生物群落的驱动因素提供了新的视角,对生物炭在人工湿地中的实际应用具有指导意义.

This study investigated the impact and mechanisms of different biochar ratios on the denitrification performance and ammonia emission reduction in surface flow constructed wetlands based on mesocosm simulations.Employing machine learning and“infer Community Assembly Mechanisms by Phylogenetic bin-based null model”(iCAMP),we further explored the microbiological mechanisms involved.The results indicated that,compared to the control group without biochar,a 50%biochar addition significantly promoted the growth of ammonia-oxidizing bacteria(e.g.,Chloroflexi,Rhodocyclaceae),enhanced NH4+-N transformation in the system,and effectively reduced ammonia emissions by 32%.Sensitive microbial species identified by the random forest model,such as Planctomycetes and Parcubacteria,could serve as preliminary indicators for ammonia volatilization flux.The proportion of biochar in constructed wetlands was closely linked to changes in community structure.An increase in biochar ratio led to a clustering of phylogenetic structures and promoted the growth and establishment of specific bacterial communities(e.g.,Gammaproteobacteria,Deltaproteobacteria)related to carbon and nitrogen cycling.This study offers a new perspective on understanding the factors driving microbial communities in constructed wetlands and provides guidance for the practical application of biochar in these ecosystems.