• 关键词：溶解性有机物  融雪  土壤  荧光光谱  化学离子

• 基金项目：国家自然科学基金（No.21107039）；辽宁省教育厅科学技术研究项目（No.L2011002）；辽宁省科学技术计划项目（No.2011230009）

• 王茜
• 辽宁大学, 环境学院, 沈阳 110036

• 薛爽
• 辽宁大学, 环境学院, 沈阳 110036

• 刘影
• 辽宁大学, 环境学院, 沈阳 110036

• 洪悦
• 辽宁大学, 环境学院, 沈阳 110036

• 刘红
• 辽宁大学, 环境学院, 沈阳 110036

• 摘要：利用土壤浸提实验和土柱淋洗实验，考察了化学离子的种类与浓度对进入融雪径流的土壤溶解性有机物（DOM）的含量和光谱学特性的影响，以及不同化学特征的积雪融化过程中土壤DOM的释放规律.土壤浸提实验结果表明，随着Na⁺、Mg²⁺和Ca²⁺浓度的升高，土壤浸提液中的溶解性有机碳（DOC）浓度显著降低；随着Cl^-、SO₄^2-、Mg²⁺和Ca²⁺浓度的升高，土壤浸提液中波长254 nm处的紫外吸光度（UV-254）逐渐降低；随着Na⁺和Mg²⁺浓度的升高，土壤浸提液中单位浓度DOC的紫外吸收值（SUVA）值逐渐升高.NO^-₃、SO₄^2-和Na⁺的浓度过高或过低时，土壤浸提液中DOM的类腐殖酸和类富里酸荧光峰强度较低；随着Cl^-、Mg²⁺和Ca²⁺浓度的升高，土壤浸提液中DOM的类腐殖酸荧光峰强度逐渐降低.土柱淋溶实验结果表明，类腐殖酸和类富里酸荧光物质是土壤淋滤液中的主要荧光物质.与纯水相比，融雪水作为淋洗液导致土壤淋滤液中DOC浓度的降低，以及类微生物代谢产物荧光峰强度的增高.冻融交替抑制DOM自土壤解吸进入淋滤液，并且导致土壤淋滤液中芳香族化合物相对含量的降低.

• Abstract：The effect of types and concentrations of chemical ions on the contents and spectroscopy characteristics of dissolved organic matter (DOM) in soil which enters snowmelt runoff, as well as the release of DOM from soil during the melting of snow with different chemical characteristics, was investigated by means of soil leaching experiments and soil column leaching experiments. The soil leaching experiment results showed that the dissolved organic carbon (DOC) concentrations in soil extracts significantly decreased with the increase of Na⁺, Mg²⁺ and Ca²⁺ concentrations. The absorbance of ultraviolet light at 254 nm (UV-254) in soil extracts gradually decreased with the increase of Cl^-, SO₄^2-, Mg²⁺ and Ca²⁺ concentrations. The specific ultraviolet light absorbance (SUVA) in soil extracts gradually increased with the increase of Na⁺ and Mg²⁺ concentrations. When NO^-₃, SO₄^2- and Na⁺concentrations were too high or too low, the intensity of humic acid-and fulvic acid-like fluorescence peaks of DOM in soil extracts was relatively low. The intensity of humic acid-like fluorescence peak of DOM in soil extracts gradually increased with the increase of Cl^-、Mg²⁺ and Ca²⁺ concentrations. The soil column leaching experiment results showed that the humic acid-and fulvic acid-like fluorophores were the main fluorescent materials in soil leachate. The snowmelt water which acted as leaching solution, compared with pure water, led to the decrease in DOC concentrations as well as the increase in intensity of soluble microbial byproduct-like fluorescence peak in soil leachates. The freezing-thawing of soil inhibited DOM from desorption from soil and entering leachates. In additon, the freezing-thawing of soil also resulted in the decrease in the relative content of aromatic compounds in soil leachates.

• Key words：dissolved organic matter  snowmelt  soil  fluorescence spectroscopy  chemical ions

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