氮负荷增强对闽江河口短叶茳芏湿地近地气层CH4浓度变化的影响  

Effects of enhanced nitrogen load on variations of methane(CH4)concentration in ambient atmosphere above Cyperus malaccensis marsh in the Minjiang estuary

作　　者：方冠荣 孙志高[1,2,3] 胡星云 李亚瑾[1,2] 宋振阳 贺攀霏 夏星辰 武慧慧 姚钦予 FANG Guanrong;SUN Zhigao;HU Xingyun;LI Yajin;SONG Zhenyang;HE Panfei;XIA Xingchen;WU Huihui;YAO Qinyu(Fujian Provincial Key Laboratory for Subtropical Resources and Environment,Fujian Normal University,Fuzhou 350007;Key Laboratory of Humid Subtropical Eco˗geographical Process(Fujian Normal University),Ministry of Education,Fuzhou 350007;Wetland Ecosystem Research Station of Minjiang Estuary,National Forestry and Grassland Administration,Fuzhou 350215)

机构地区：[1]福建师范大学福建省亚热带资源与环境重点实验室,福州350007 [2]福建师范大学湿润亚热带生态地理过程教育部重点实验室,福州350007 [3]福建闽江河口湿地生态系统国家定位观测研究站(国家林业和草原局),福州350215

出　　处：《环境科学学报》2024年第1期503-515,共13页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金面上项目(No.42371105,41971128);福建省自然科学基金重点项目(No.2023J02012);福建省“闽江学者奖励计划”项目。

摘　　要：2021年3月—2022年2月,选择闽江河口鳝鱼滩的短叶茳芏湿地为研究对象,基于野外原位氮负荷增强模拟试验,探讨了不同氮负荷水平(N0,无氮负荷处理,0g·m^(-2)·a^(-1);NL,低氮负荷处理,12.5 g·m^(-2)·a^(-1);NM,中氮负荷处理,25.0g·m^(-2)·a^(-1);NH,高氮负荷处理,75.0 g·m^(-2)·a^(-1))对湿地近地气层甲烷(CH_(4))浓度时空变化的影响.结果表明,不同氮负荷增强条件下湿地近地气层的CH_(4)浓度呈现出不同的月动态变化特征;不同处理下的CH_(4)浓度均在氮负荷持续5个月后最低,在持续9个月后最高.随着氮负荷时间的延长,近地气层的CH_(4)浓度整体以NH处理最高((2.032±0.554)mL·L^(-1)),NL((1.937±0.618)mL·L^(-1))和NM((1.889±0.589)mL·L^(-1))处理次之,而N0处理最低((1.830±0.647)mL·L^(-1)).不同氮负荷处理下湿地近地气层的CH_(4)浓度在每次氮负荷后的1 h和3h整体低于氮负荷前,原因可能与每次氮负荷时的铵态氮(NH_(4)^(+)-N)与硝态氮(NO_(3)^(-)-N)输入比例以及输入时间有关.不同氮负荷水平下湿地近地气层的CH_(4)浓度整体均随高度增加而降低;除NL处理的CH_(4)平均浓度在0.3 m取得最高值外,其他处理的CH_(4)浓度均在0m最高.研究发现,氮负荷增强条件下湿地近地气层CH_(4)浓度的时间变化主要与土壤氮养分状况改变以及温度、Eh等主要因子的变化有关,而其垂直变化可能主要受风速和植物生态特征(株高、密度)的显著影响.From March 2021 to February 2022,the typical Cyperus malaccensis marsh in Shanyutan of the Minjiang estuary was selected as study object and the effects of enhanced nitrogen(N)load on spatiotemporal variations of methane(CH_(4))concentration in ambient atmosphere were investigated by field N load experiment which included four N load levels(N0,no N load treatment,0 g·m^(-2)·a^(-1);NL,low N load treatment,12.5 g·m^(-2)·a^(-1);NM,medium N load treatment,25 g·m^(-2)·a^(-1);and NH,high N load treatment,75 g·m^(-2)·a^(-1)).Results showed that,as affected by different N load levels,the concentrations of CH_(4)in ambient atmosphere above marsh showed distinct monthly variations.The lowest CH_(4)concentrations in different N load treatments were observed after the N load lasted for five months,while the highest values occurred after the N load lasted for nine months.With the extension of N load duration,the concentrations of CH_(4)in ambient atmosphere above marsh generally followed the order of NH((2.032±0.554)mL·L^(-1))>NL((1.937±0.618)mL·L^(-1))>NM((1.889±0.589)mL·L^(-1))>N0((1.830±0.647)mL·L^(-1)).At each N load period,the concentrations of CH_(4)in ambient atmosphere after 1 h and 3 h were much lower than those before N load,which might be related to the import ratio of ammonium nitrogen(NH_(4)^(+)-N)and nitrate nitrogen(NO_(3)^(-)-N)and the duration of each N import.Under different N load levels,the concentrations of CH_(4)in ambient atmosphere above marsh generally decreased with increasing heights.The mean concentration of CH_(4)in the NL treatment reached the maximum at 0.3 m,while the values in the other treatments achieved the maximus at 0 m.This study found that the temporal variations of CH_(4)concentration in ambient atmosphere above marsh primarily rested with the alterations of soil N nutrient and the changes of temperature and Eh,whereas the vertical variations of CH_(4)concentration were significantly influenced by wind speed and plant ecological traits(e.g.,height and density).

关 键 词：CH4 氮负荷 垂直变化 短叶茳芏湿地 闽江河口 

分 类 号：X17[环境科学与工程—环境科学]