不同氮负荷水平下闽江河口芦苇残体分解及硫养分释放特征  

Decomposition and sulfur release from Phragmites australis under different nitrogen load in the Minjiang River estuary

作　　者：贺攀霏 孙志高[1,2,3] 宋振阳 陈冰冰 夏星辰[1,2] 武慧慧 方冠荣 姚钦予 HE Panfei;SUN Zhigao;SONG Zhenyang;CHEN Bingbing;XIA Xingchen;WU Huihui;FANG Guanrong;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;College of Tourism,Resources and Environment,Zaozhuang University,Zaozhuang 277000)

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 [4]枣庄学院旅游与资源环境学院,枣庄277000

出　　处：《环境科学学报》2024年第3期387-398,共12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：河口湿地是响应全球气候变化和人类活动最为敏感的生态系统之一,是外源氮的一个重要“汇”,其对于残体分解及生源元素释放过程可产生深刻影响.作为湿地重要的生源元素之一,硫在植物生长发育以及维持湿地稳定性方面扮演着重要角色.在当前闽江河口氮负荷增强背景下,探讨残体分解及硫养分释放特征对氮负荷增强的响应具有重要意义.为此,2021年3月—2022年12月,选择闽江河口芦苇(Phragmites australis)湿地为研究对象,基于野外氮负荷增强模拟试验,探讨了不同氮负荷水平下(NL0,对照处理,0 g·m^(-2)·a^(-1);NL1,低氮处理,12.5 g·m^(-2)·a^(-1);NL2,中氮处理,25.0 g·m^(-2)·a^(-1);NL3,高氮处理,75.0 g N·m^(-2)·a^(-1))芦苇残体分解及硫养分释放特征.结果表明,不同氮负荷处理下残体的分解速率在分解期间(0~630 d)整体表现为NL3(0.00255 d^(-1))>NL2(0.00252 d^(-1))>NL1(0.00219 d^(-1))>NL0(0.00194 d^(-1));相较于NL0处理,NL1、NL2和NL3处理下的分解速率分别增加了12.89%、29.90%和31.44%.尽管NL1和NL3处理对0~270 d的残体分解可产生一定的抑制作用,而该抑制作用在270~630 d又转变为促进作用.不同氮负荷处理下残体中的TS含量在分解期间均呈波动增加趋势,其中NL1处理下残体的TS含量整体高于NL0处理,但NL2和NL3处理下的TS含量整体低于NL0处理.随着氮负荷水平的升高,影响残体TS含量变化的关键因子由NL0处理下的N/S(R^(2)=0.869,p<0.01)转变为NL1处理下的残留率(R^(2)=0.883,p<0.01),而在NL2处理下又转变为C/S(R^(2)=0.769,p<0.01);但在NL3处理下,其TS含量变化主要受残留率、C/N和pH的共同影响(R2=0.958,p<0.05).不同氮负荷处理下残体中的硫养分在0~180d均表现为不同程度的净释放;但在180~630 d,NL0和NL1处理表现为不同程度的净累积,而NL2和NL3处理表现为不同程度的净释放.研究发现,中、高氮负荷条件下芦苇残体的分解速率较高,且随着分解时�Estuarine marsh is one of the most sensitive ecosystems that respond to global change and human activities.The estuarine marsh generally acts as a sink of exogenous nitrogen(N),which might produce significantly influences on the processes of litter decomposition and biogenic element release.As one of the most important biogenic elements in estuarine marsh,sulfur(S)plays important roles in plant growth and development and in maintaining marsh stability.In the background of enhanced exogenous N import in the Minjiang estuary,it is significance to explore the responses of litter decomposition and S release to the enhanced N load.this study,spanning March 2021 to December 2022,investigated the effects of enhanced N loads on decomposition and S release of Phragmites australis litters in the Minjiang estuary.A field N load experiment encompassing four N load levels(NL0,0 g·m^(-2)·a^(-1);NL1,12.5 g·m^(-2)·a^(-1);NL2,25.0 g·m^(-2)·a^(-1);and NL3,75.0 g N·m^(-2)·a^(-1))was conducted.Results showed that the decomposition rates of P.australis litters generally followed the order:NL3(0.00255 d-1)>NL2(0.00252 d-1)>NL1(0.00219 d-1)>NL0(0.00194 d-1)during 0~630 days.Compared to NL0 treatment,the decomposition rates in the NL1,NL2 and NL3 treatments increased by 12.89%,29.90%,and 31.44%,respectively.Although NL1 and NL3 treatments inhibited the decomposition of detritus during 0~270 days,they shifted to promoting decomposition(270~630 days).total sulfur(TS)content in decomposing litters generally increased during decomposition.NL1 displayed higher TS than NL0,while NL2 and NL3 exhibited lower TS.With increasing N load levels,the key variables influencing the variation of TS contents in detritus changed from N/S in the NL0 treatment(R2=0.869,p<0.01)to mass remaining in the NL1 treatment(R2=0.883,p<0.01)or C/S in the NL2 treatment(R2=0.769,p<0.01).By comparison,the variation of TS contents in the NL3 treatment was mainly controlled by mass remaining,C/N and pH(R2=0.958,p<0.05).sulfur Stocks in decomposing litters in differ

关 键 词：残体分解 氮负荷 硫 芦苇 闽江河口 

分 类 号：X17[环境科学与工程—环境科学]