| 基于EEM-PARAFAC分析冻融作用对高寒泥炭湿地土壤溶解性有机质的影响 |
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| 引用本文： | 王鹏,商帅帅,郭璠,邱景琮,王鑫晴,王诗淇,王春梅.基于EEM-PARAFAC分析冻融作用对高寒泥炭湿地土壤溶解性有机质的影响[J].北京林业大学学报,2021,43(11):99-108. |
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| 作者姓名： | 王鹏 商帅帅 郭璠 邱景琮 王鑫晴 王诗淇 王春梅 |
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| 作者单位： | 北京林业大学环境科学与工程学院，北京 100083 |
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| 基金项目： | 国家自然科学基金项目（41971024、41373069），北京林业大学大学生创新创业训练项目（S202010022338） |
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| 摘 要： | 目的 全球气候变暖加速了土壤冻融格局的改变，而冻融作用又对土壤溶解性有机质（DOM）产生深刻的影响。 方法 以高寒泥炭湿地土壤为研究对象，采用室内模拟冻融的方式开展了两种冻融条件下（日冻融:?3 ℃/5 ℃，12 h/12 h，30次；深度冻融:?24 ℃/5 ℃，20 d/10 d，1次）的试验研究，基于紫外?可见吸收光谱（UV-vis）和三维荧光光谱结合平行因子（EEM-PARAFAC）分析探究土壤DOM数量和质量的变化。 结果 （1）经过30 d培养后，两种冻融处理均显著提高了高寒泥炭湿地土壤溶解性有机碳（DOC）的含量，日冻融和深度冻融条件下土壤样品的DOC含量分别为183.26和187.06 mg/kg，相比于对照组分别增加了18.80%和21.26%（P < 0.05）。（2）不同冻融条件下的土壤DOM的紫外?可见吸收曲线线型差异较小，无明显特征吸收峰，且显示出吸光度随波长呈指数衰减的趋势，但经冻融处理的样品出现了明显的红移现象。（3）两种冻融处理均使得土壤DOM的腐殖化指数（HIX）值（从4.42增加至11.73和17.10）、254 nm处的单位比色皿光程下的紫外吸收值（SUVA254）（从1.35 mg/（L·cm）增加至1.37和1.40 mg/（L·cm））以及A253/A203值（0.38增加至0.40和0.43）增大，波长275 ~ 295 nm处光谱斜率系数减小（从13.34 μm?1减小至13.23和12.91 μm?1）。（4）EEM-PARAFAC鉴别出的荧光组分有类富里酸物质、类腐殖酸物质、溶解性微生物代谢产物和类蛋白物质，冻融改变了土壤DOM的组成以及各组分的贡献率。对照组土壤DOM组分C1、C2和C3的贡献率分别为37%、32%和31%；日冻融条件下，组分C1、C2和C3的贡献率分别为41%、34%和 25%；深度冻融条件下，组分C1、C2和C3的贡献率分别为44%、35%和 21%。 结论 冻融改变了土壤DOM的数量和质量，表现为DOC含量的增加和腐殖化程度的提高。
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| 关 键 词： | 冻融 湿地土壤 溶解性有机质 紫外?可见吸收光谱 三维荧光光谱?平行因子分析 |
| 收稿时间： | 2021-03-15 |
Analyzing the effects of freeze-thaw on dissolved organic matter in alpine peat wetland soil based on EEM-PARAFAC |
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| Wang Peng,Shang Shuaishuai,Guo Fan,Qiu Jingcong,Wang Xinqing,Wang Shiqi,Wang Chunmei.Analyzing the effects of freeze-thaw on dissolved organic matter in alpine peat wetland soil based on EEM-PARAFAC[J].Journal of Beijing Forestry University,2021,43(11):99-108. |
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| Authors: | Wang Peng Shang Shuaishuai Guo Fan Qiu Jingcong Wang Xinqing Wang Shiqi Wang Chunmei |
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| Institution: | School of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China |
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| Abstract: | Objective Global warming has accelerated changes in soil freeze-thaw patterns, and it is important to clarify the effects of freeze-thaw on dissolved organic matter (DOM) in soils. Method Experimental studies were conducted in alpine peat wetland soils under two freeze-thaw conditions (daily freeze-thaw: ?3 ℃/5 ℃, 12 h/12 h, 30 times; deep freeze-thaw: ?24 ℃/5 ℃, 20 d/10 d, 1 time) using simulated freeze-thaw methods. The changes in soil DOM quantity and quality were investigated based on ultraviolet-visible absorption spectroscopy (UV-vis) and three-dimensional fluorescence spectroscopy combined with parallel factor (EEM-PARAFAC) analysis. Result (1) After 30 d of incubation, the soil dissolved organic carbon (DOC) content was significantly increased. The DOC content of soil samples under day freeze-thaw and deep freeze-thaw conditions was 183.26 and 187.06 mg/kg, respectively, which increased by 18.80% and 21.26% compared with control group (P < 0.05). (2) The UV-vis absorption curves of soil DOM under different freeze-thaw conditions showed little difference, with no obvious characteristic absorption peak, and the absorbance decreased exponentially with the wavelength, but the freeze-thaw samples showed obvious red shift phenomenon. (3) Both freeze-thaw treatments resulted in increased HIX (from 4.42 to 11.73 and 17.10), SUVA254 (from 1.35 mg/(L·cm) to 1.37 and 1.40 mg/(L·cm)) and A253/A203 values (from 0.38 to 0.40 and 0.43) and decreased spectral slope coefficient at wavelength of 275?295 (from 13.34 μm?1 to 13.23 and 12.91 μm?1) of soil DOM. (4) The fluorescent components identified by EEM-PARAFAC included fulvic acid-like substances, humic acid-like substances, soluble microbial metabolites and protein-like substances. Freeze-thaw changed the composition of soil DOM and the percentage of PARAFAC-derived components. The proportions of the three PARAFAC-derived components in the control group were 37%, 32% and 31%, in the daily freeze-thaw group were 41%, 34% and 25% and in the deep freeze-thaw group were 44%, 35% and 21%, respectively. Conclusion Freeze-thaw changes the quantity and quality of DOM in soils, which is manifested in the increase of DOC content and the enhancement of humification degree. |
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