摘要
有色可溶性有机物(CDOM)作为溶解性有机物的重要光学组分,会影响内陆水体污染物质的迁移和湿地碳循环过程.目前有关长江中下游湖泊CDOM的研究主要集中于湖泊水体CDOM的组成特征分析,针对湖泊湿地不同植被枯落物在降雨淋溶过程中的CDOM输出及其影响机制尚缺乏深入研究.因此,本文选取鄱阳湖湿地3种优势植被(苔草、南荻和芦苇)为研究对象,采用室内模拟降雨淋溶的方法,模拟洲滩植被和土壤在降雨-径流条件下淋溶CDOM的产生迁移过程.同时,利用紫外-可见吸收光谱和三维荧光光谱-平行因子分析法(EEMs-PARAFAC)分析鄱阳湖湿地3种优势植被枯落物淋溶CDOM的光谱特征.结果表明:①模拟降雨条件下淋溶CDOM和DOC浓度因不同的土地覆被具有明显差异,淋溶CODM和DOC的浓度表现为苔草>芦苇>南荻.②运用EEMs-PARAFAC方法解析出3种类腐殖质荧光组分和1种类色氨酸荧光组分,并且类腐殖质荧光组分(C1+C2+C3)和类色氨酸荧光组分C4对总荧光强度的贡献率分别为75.44%和24.56%.③芳香性指数(SUVA_(254))、荧光指数(FI)、生物源指数(BIX)和腐殖化指数(HIX)表明,鄱阳湖优势植被枯落物淋溶CDOM腐殖化程度较低,新近自生源特征明显且与微生物作用联系紧密.研究结果可为鄱阳湖湿地CDOM的生物地球化学过程提供基础数据和科学参考.
Chromophoric dissolved organic matter(CDOM)is an important component of dissolved organic matter that affects the migration of pollutants and the carbon cycle,especially in wetlands.Analyses of CDOM in lakes of the middle and lower reaches of the Yangtze River has previously been confined to consideration of CDOM composition characteristics.However,a better understanding of the process and mechanism which influence CDOM leaching in wetlands is required.Here,we consider three dominant plant species of the Poyang Lake wetlands(Carex cinerascens:C.cinerascens,Triarrhena lutarioriparia:T.lutarioriparia,Phragmites australis:P.australis)to simulated the output and migration process of CDOM leaching from plant and surface soil under rainfall-runoff conditions in a laboratory.The spectral characteristics of the leaching CDOM from these species were analyzed by UV-visible absorption spectrum and fluorescence spectrum-parallel factor analysis(EEMs-PARAFAC).Results showed that:①Concentrations of CDOM and DOC under simulated rainfall varied significantly with different land cover types.C.cinerascens experienced the most significant leaching of CDOM and DOC,followed by T.lutarioriparia and P.australis.②Three humic and one tryptophan fluorescence components were identified by the EEMs-PARAFAC method.The contribution of the humic fluorescence component and the tryptophan fluorescence component to total fluorescence intensity were 75.44%and 24.56%,respectively.③The spectral characteristic parameters of the aromaticity index(SUVA_(254)),fluorescence index(FI),biological index(BIX)and humification index(HIX)showed that CDOM leaching from the dominant plant litter in Poyang Lake had a low degree of humification,and its recent autogeny is likely related to microbial action.Our results can provide guidance for future studies of the biogeochemical processes of CDOM in the Poyang Lake wetlands.
作者
刘甲庆
王伟
徐健
简正军
胡启武
LIU Jiaqing;WANG Wei;XU Jian;JIAN Zhengjun;HU Qiwu(Key Laboratory of Poyang Lake Wetland and Watershed Research Ministry of Education,School of Geography and Environment,Jiangxi Normal University,Nanchang 330022;Geographic Information Engineering Brigade,Jiangxi Provincial Bureau of Geology,Nanchang 330001)
出处
《环境科学学报》
CAS
CSCD
北大核心
2023年第11期338-349,共12页
Acta Scientiae Circumstantiae
基金
国家自然科学基金(No.32060275)
江西省教育厅科学技术研究项目(No.GJJ2200326)
江西鄱阳湖湿地生态系统监测预警平台建设项目(No.2202-360000-04-01-502976)
江西省研究生创新基金(No.YC2022-S248)。
