淹水条件下三峡库区典型消落带土壤释放DOM的光谱特征：紫外-可见吸收光谱  

Spectral Characteristics of Dissolved Organic Matter( DOM ) Releases from Soils of Typical Water-Level Fluctuation Zones of Three Gorges Reservoir Areas: UV-Vis Spectrum

作　　者：梁俭[1] 江韬[1,2] 卢松[1] 魏世强[1] 王定勇[1] 陈雪霜[1] 王齐磊[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, Umea SE-90183, Sweden

出　　处：《环境科学》2016年第7期2496-2505,共10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(cstc2015jcyj A20021);重庆市博士后科研项目(Xm2014023);中国博士后科学基金项目(2013M542238);中央高校基本科研业务费专项基金重点项目(XDJK2015B035)

摘　　要：消落带土壤在淹水发生时释放溶解性有机质(DOM),是上覆水体DOM的重要来源.但同时对淹水释放DOM进行定量定性分析的报道并不多见.本文以三峡库区典型消落带为研究对象,通过模拟实验,利用紫外-可见吸收光谱,研究了厌氧淹水和正常淹水条件下,淹水土壤释放DOM的光谱特征.结果表明,消落带4个区域土壤淹水均呈'快速释放-下降-动态平衡'释放规律;释放速率和通量计算表明,DOM释放呈现出'源-汇动态交换'特征.对比两种淹水处理,尽管溶解性有机碳(DOC)和有色溶解性有机质(CDOM)无显著差异,但厌氧淹水DOM芳香性(SUVA280)高于正常淹水,而光谱斜率比值(SR)对不同淹水条件不敏感.同时,厌氧淹水时,DOC和CDOM的相关性也明显高于正常淹水.另外,各区域土壤淹水释放DOM存在差异,以忠县石宝寨土壤释放强度最高,尽管土壤有机质含量是影响各区域土壤淹水释放DOM差异的重要原因之一,但其他地化因素仍需考虑.因此,仅仅关注DOC浓度变化并不足以完全描述DOM的释放特征.Water-level fluctuation zone is an important area in Three Gorges Reservoir areas,because dissolved organic matter（ DOM）releases from submerged soils is a crucial source of DOM in overlying waters when flooding occurs. But there was little qualitative and quantitative analysis for DOM. In this study,soils of four typical water-level fluctuation zones were selected to conduct simulated flooding experiment. Also,UV-Vis spectroscopy was utilized to investigate the DOM spectral characteristics in two individual flooding sets including ambient（ open air） and anoxic conditions. The results showed,for all soils,the DOM release patterns all showed a＂rapid release,then decrease,and final dynamic equilibrium＂trend. Also,through calculations of DOM releasing rates and fluxes,DOM releases clearly showed a feature of ＂source-sink dynamic exchange＂. By comparison between two flooding treatments,although DOC and CDOM didn＇t show any significant differences,but higher aromaticity（ SUVA280） was observed in anoxic experiment. In contrast,spectra slope ratio（ SR） was insensitive to redox conditions of different flooding. Meanwhile,correlation between DOC and CDOM in anoxic was also higher than that in ambient flooding. Additionally,obvious differences among soils from different sampling sites were observed,Shibao Zhai（ SB） of which showed the greatest releasing potential. Considering the various soil properties,soil organic matter amounts in soils is one of the key factors to explain the differences among sampling sites,but other geochemical factors should also be considered in the processes of DOM releases. Summarily,only focusing on the changes of DOC concentrations in submerging process is not enough to comprehensively describe the DOM release characteristics.

关 键 词：溶解性有机质 三峡库区 消落带 淹水 溶解性有机碳 紫外-可见吸收光谱 土壤 

分 类 号：X144[环境科学与工程—环境科学]