| 三峡库区典型消落带土壤及沉积物中溶解性有机质(DOM)的紫外-可见光谱特征 |
| 摘要点击 5275 全文点击 2285 投稿时间：2013-07-05 修订日期：2013-10-22 |
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| 中文关键词 溶解性有机质 紫外-可见光谱 吸收光谱模型 三峡库区 消落带 光漂白 生物降解 |
| 英文关键词 dissolved organic matter (DOM) UV-Vis spectra absorption spectra model Three Gorges Reservoir areas water-level fluctuation zones photobleach biodegradation |
| 作者 | 单位 | E-mail | | 李璐璐 | 西南大学资源环境学院, 重庆 400716 | lululee407@gmail.com | | 江韬 | 西南大学资源环境学院, 重庆 400716
重庆市农业资源与环境研究重点实验室, 重庆 400716 | Jiangtower666@163.com | | 闫金龙 | 西南大学资源环境学院, 重庆 400716 | | | 郭念 | 西南大学资源环境学院, 重庆 400716 | | | 魏世强 | 西南大学资源环境学院, 重庆 400716
重庆市农业资源与环境研究重点实验室, 重庆 400716 | | | 王定勇 | 西南大学资源环境学院, 重庆 400716
重庆市农业资源与环境研究重点实验室, 重庆 400716 | | | 高洁 | 西南大学资源环境学院, 重庆 400716 | | | 赵铮 | 西南大学资源环境学院, 重庆 400716 | |
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| 中文摘要 |
| 溶解性有机质（DOM）是陆地生态系统的重要组成部分，在环境地球化学中扮演着重要角色. 在测定三峡库区典型消落带土壤及沉积物DOM的紫外-可见光谱基础上，通过特征参数及光谱模型来获取DOM的地化特征和信息. 紫外-可见光谱特征参数表明土壤DOM的芳香性、疏水组分及腐殖化程度都明显低于上层沉积物，与高程和土地利用类型无关；而所选择的4种吸收光谱模型中以模型2为最优. 同时，不同模型和不同拟合波段均对DOM光谱曲线斜率（S）有影响：S值随波长增加而减小；而不同波段S值相关性存在差异，表明各波段S值仅反映DOM部分信息，而非全部. 此外，特征斜率之比（SR）反映出表层沉积物所受降解程度（光漂白或生物降解）小于土壤和往年沉积物，其芳香性更高，分子量更大，参与降解的反应活性也更大；这表明DOM越新鲜，其受到的光照和生物作用相对较小，降解潜力越大. |
| 英文摘要 |
| Dissolved organic matter (DOM) is a very important component in terrestrial ecosystem, which also plays a key role in geo-environmental chemistry. A number of DOM samples were extracted from soils and sediments samples obtained from typical water-level fluctuation zones of Three Gorges reservoir areas. Ultraviolet-visible (UV-Vis) absorption spectra were recorded for unveiling the geochemical characteristics of DOM based on specific absorption parameters and fitting models. Through the results of specific absorption parameters, it was suggested that the aromaticity, hydrophobicity and humification degree were lower in soils than in the surface sediments, which were also independent of the sampling location height and land-use types. Among the four absorption models selected, model 2 was the optimal. Meanwhile, different models and fitting wavelengths also significantly affected the absorption spectral slope (S value): S increased with the decreasing wavelength. Additionally, the correlation among different S values obtained from different fitting wavelength ranges was significantly different suggesting that the S values in various wavelength ranges only indicated the tip of the iceberg of DOM characteristics instead of the entirety. Furthermore, the ratio of specific spectral slope (SR) indicated lower degradation (photo-bleaching or microbial degradation) degree in the surface sediments as compared to those in soils and older sediments. The surface sediments had higher aromaticity, hydrophobicity, molecular weight and photochemical/biodegradation activity potentials, suggesting fresher DOM, lower effect of photobleaching and microbial degradation activities. |
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