摘要
有色可溶性有机物(CDOM)在水生态系统的生物地球化学循环中起着重要的作用.近年来,在全球气候变暖和人类活动的双重影响下,全球大部分湖泊出现了水文隔离现象.然而,水文隔离如何影响大型湖泊CDOM组成变化仍然知之甚少.本研究于2021年在鄱阳湖碟形湖和通江水域采集水样,运用紫外-可见吸收光谱与三维荧光光谱,结合平行因子分析法(PARAFAC)研究CDOM光学特性,揭示鄱阳湖碟形湖和通江水域CDOM组成和来源的差异.结果表明:①碟形湖溶解性有机碳(DOC)浓度以及CDOM在355 nm处的吸收系数〔a(355)〕的平均值均显著高于通江水域(p<0.001),表明受水文隔离影响的碟形湖水体中存在更丰富的有机物.②基于PARAFAC分析得出的类腐殖质荧光组分(C1、C2)和蛋白质荧光组分(C3)最大荧光强度值(Fmax)的平均值均表现为碟形湖高于通江水域;碟形湖和通江水域的类腐殖质组分(C1+C2)占总荧光强度的比例分别为71.96%和59.93%,且通江水域CDOM中蛋白质荧光组分C3的贡献率高于碟形湖.③通过碟形湖和通江水域CDOM特征参数的对比分析,得出碟形湖CDOM相对分子量和腐殖化程度均高于通江水域.研究显示,水文隔离对鄱阳湖CDOM空间分布及组成变化有显著的影响.
Chromophoric dissolved organic matter(CDOM)plays an important role in the biogeochemical cycles of aquatic ecosystems.In recent years,under the dual influence of global warming and human activities,hydrological isolation has occurred in most lakes over the world.However,how hydrological isolation affects variations of CDOM chemistry in large lake systems is still poorly understood.In 2021,water samples were collected from the sub-lakes and main lake of Poyang Lake.The optical characteristics of CDOM were analyzed by UV-Vis absorption spectroscopy and 3D fluorescence spectroscopy combined with parallel factor analysis(PARAFAC)to reveal the differences in the composition and source of CDOM between the sub-lakes and main lake of Poyang Lake.The results showed that:(1)The mean values of dissolved organic carbon(DOC)and absorption coefficients of CDOM at 355 nm in sub-lakes was significantly higher than that in main lake(p<0.001).The results revealed more abundance of organic matter in sub-lakes than that in the main lake.(2)Three fluorescence components were identified by PARAFAC,including two humic-like components(C1,C2)and one protein-like component(C3).The average maximum fluorescence intensity(Fmax)of CDOM fluorescence components C1-C3 in Poyang Lake showed that its concentration in the sub-lakes was higher than that in the main lake.The proportion of humic-like components(C1+C2)to the total fluorescence intensity in sub-lakes and main lake were 71.96%and 59.93%,respectively.The proportion of protein fluorescence component C3 in CDOM in main lake was higher than that in sub-lakes.(3)The analysis of the characteristic parameters of CDOM in the sub-lakes and the main lake showed that the relative molecular weight and humic degrees of CDOM in the sub-lakes were higher than those in the main lake.This study demonstrated that hydrologic isolation had significant impact on the spatial distribution and composition variations of CDOM in Poyang Lake.
作者
简正军
徐健
刘甲庆
胡启武
JIAN Zhengjun;XU Jian;LIU Jiaqing;HU Qiwu(Ministry of Education′s Key Laboratory of Poyang Lake Wetland and Watershed Research,School of Geography and Environment,Jiangxi Normal University,Nanchang 330022,China)
出处
《环境科学研究》
CAS
CSCD
北大核心
2024年第4期741-751,共11页
Research of Environmental Sciences
基金
国家自然科学基金项目(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)。
关键词
鄱阳湖
水文隔离
有色可溶性有机物(CDOM)
荧光组成差异
来源解析
Poyang Lake
hydrological isolation
chromophoric dissolved organic matter(CDOM)
differences in fluorescence composition
source analysis
