三峡库区消落带水体DOM不同分子量组分三维荧光特征  

Three-dimensional Fluorescence Spectral Characteristics of Different Molecular Weight Fractionations of Dissolved Organic Matter in the Water-level Fluctuation Zones of Three Gorges Reservoir Areas

作　　者：陈雪霜[1] 江韬[1,2] 卢松[1] 魏世强[1] 王定勇[1] 闫金龙[1] 

机构地区：[1]西南大学资源环境学院,三峡库区生态环境教育部重点实验室,重庆市农业资源与环境研究重点实验室,重庆400716 [2]Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Sweden Umea SE-90183

出　　处：《环境科学》2016年第3期884-892,共9页Environmental Science

基　　金：国家自然科学基金项目(41403079);重庆市科委基础与前沿研究计划项目(cstc2015jcyjA20021);国家级大学生创新创业训练计划项目(201310635054);重庆市博士后科研项目(Xm2014023);中央高校基本业务费专项(XDJK2015B035);中国博士后科学基金项目(2013M542238)

摘　　要：本研究利用超滤技术和三维荧光光谱,以三峡库区典型消落带水体溶解性有机质（DOM）不同分子量组分为对象,分析和讨论了不同分子量级分的组成差异和输入来源.结果表明,该区域DOM分子量分布情况较为分散,但胶体（M_r1×10~3~0.22μm）和真溶态组分（M_r〈1×10~3）均对DOC总质量贡献相当.不同分子量级分中均存在A、C、B、T峰,其相对含量分配均呈现出一致趋势,即真溶态（M_r〈1×10~3）〉低分子量组分（M_r1×10~3~10×10~3）〉中分子量组分（M_r10×10~3~30×10~3）〉高分子量组分（M_r30×10~3~0.22μm）.另外,DOM随超滤分子量等级降低,FI和BIX值增加,＂内源＂输入特征增强;腐殖化程度降低（HIX值下降）.陆源输入主要影响高、中分子组分,而内源输入主要影响低分子及真溶态部分.同时,沿岸不同土地利用类型对水体DOM性质和组成影响明显.土地利用类型多样性、生态景观结构复杂程度越高,水体DOM不同分子量等级中各荧光组分也越复杂.The study of the molecular weight（ MW） fractions of dissolved organic matter（ DOM） in aquatic environment is of interests because the size plays an important role in deciding the biogeochemical characteristics of DOM. Thus,using ultrafiltration（ UF）technique combined with three-dimensional fluorescence spectroscopy,DOM samples from four sampling sites in typical water-level fluctuation zones of Three Gorge Reservoir areas were selected to investigate the differences of properties and sources of different DOM MW fractions. The results showed that in these areas,the distribution of MW fractions was highly dispersive,but the approximately equal contributions from colloidal（ M_r1 × 10~3-0. 22 μm） and true dissolved fraction（ M_r 1 × 10~3） to the total DOC concentration were found. Four fluorescence signals（ humic-like A and C; protein-like B and T） were observed in all MW fractions including bulk DOM,which showed the same distribution trend： true dissolved low MW（ M_r1 × 10~3-10 × 10~3） medium MW（ M_r10 × 10~3-30 ×10~3） high MW（ M_r30 × 10~3-0. 22 μm）. Additionally,with decreasing MW fraction,fluorescence index（ FI） and freshness index（ BIX） increased suggesting enhanced signals of autochthonous inputs,whereas humification index（ HIX） decreased indicating lower humification degree. It strongly suggested that terrestrial input mainly affected the composition and property of higher MW fractions of DOM,as compared to lower MW and true dissolved fractions that were controlled by autochthonous sources such as microbial and alga activities,instead of allochthonous sources. Meanwhile, the riparian different land-use types also affected obviously on the characteristics of DOM. Therefore,higher diversity of land-use types,and also higher complexity of ecosystem and landscapes,induced higher heterogeneity of fluorescence components in different MW fraction of DOM.

关 键 词：溶解性有机质 超滤 三维荧光光谱 三峡库区 消落带 水体有机胶体 

分 类 号：X131.2[环境科学与工程—环境科学] X52