| 黄土高原高浑浊水体CDOM光学特性及影响因素 |
| 摘要点击 1855 全文点击 699 投稿时间：2019-08-30 修订日期：2019-10-31 |
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| 中文关键词 黄土高原 有色溶解有机物(CDOM) 光学特性 水质参数 冗余分析(RDA) |
| 英文关键词 Loess Plateau chromophoric dissolved organic matter (CDOM) optical properties water quality parameters redundancy analysis (RDA) |
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| 中文摘要 |
| 为确定黄土高原地区高浑浊水体有色溶解有机物（CDOM）组成来源及研究环境因素对其的影响，本文基于2018年5月陕蒙黄土高原地区河流与湖泊（咸水湖和淡水湖）的实测数据对CDOM光学吸收特性，各组分对水体吸收的贡献，光谱斜率S275~295及水质参数与CDOM光学特征参数的相关性进行分析.结果表明，陕蒙黄土高原区河湖CDOM吸收光学特性差异显著（P<0.01），湖泊CDOM吸收系数aCDOM（440）（8.45 m-1）高于河流（2.70 m-1），咸水湖CDOM浓度（13.52 m-1）高于淡水湖（3.38 m-1），淡水湖对光的有效利用率高于咸水湖和浑浊河流.河流与湖泊、咸淡水湖之间酸碱度（pH）和溶解有机碳（DOC）差异均呈显著水平（P<0.01）；河湖水体电导率（EC）、浊度（Tur）和总悬浮物浓度（TSM）差异显著；排除极大值点，咸水湖与淡水湖叶绿素a（Chla）相接近.基于S275~295分析发现，湖泊CDOM分子量小于河流，咸水湖分子量小于淡水湖；由SUVA254得出，河流陆源腐殖质输入比湖泊多，淡水湖陆源腐殖质输入较咸水湖多.通过冗余分析（RDA）发现，河流与湖泊水质参数累积方差解释率分别为35.2%和61.4%，咸淡水湖均达到100%；溶解氧（DO）、水温和EC对河流CDOM光学特性影响较大（P<0.01），而DOC、TSM和Tur对湖泊CDOM光学特性影响较大（P<0.01）；咸水湖水体中DOC以及淡水湖水体的pH与CDOM吸收系数相关性较强（P<0.05）. |
| 英文摘要 |
| Chromophoric dissolved organic matter (CDOM) optical absorption characteristics, CDOM spectral slopes (S275-295), contribution of each component to water absorption, and the effects of environmental factors on them were analyzed to determine the sources and composition of CDOM in high-turbidity waters on the Loess Plateau. Samples in rivers and lakes (saline and freshwater) in the Loess Plateau area of Shaanxi and Inner Mongolia were collected in May 2018. The results demonstrated significant differences in CDOM absorption optical characteristics between rivers and lakes. The average aCDOM(440) (CDOM concentration, 8.45 m-1) in lakes was higher than that of rivers (2.70 m-1), and the saline lakes showed a higher CDOM concentration (13.52 m-1) than the freshwater lakes (3.38 m-1). Moreover, the light utilization efficiency of freshwater lakes is higher than that of saline lakes and turbid rivers. Great differences in pH and dissolved organic carbon (DOC) were observed between different types of water (P<0.01). The differences in electrical conductivity (EC), turbidity (Tur), and total suspended matter concentration (TSM) were significant with no statistical significances (P>0.1). The chlorophyll a concentration (Chla) in saline lakes was close to the Chla concentration in freshwater lakes if extreme values were excluded. In addition, the CDOM molecular weights of lake water were lower than those in the rivers, while CDOM molecular weights in saline lakes were lower than those in freshwater lakes based on the S275-295. Analyses of specific ultraviolet absorbance (SUVA254) were also conducted to determine the sources of CDOM in different water types, and the results showed that the more terrigenous humus were brought into the rivers and saline lakes compared with the freshwater lakes. Redundancy analysis (RDA) indicated that river and lake water quality parameters of the cumulative variance explained rates were 35.2% for river samples and 61.4% for lake samples, and 100% for samples in the saline and freshwater lakes individually. The results of RDA showed that dissolved oxygen (DO), water temperature, and EC exerted significant effects on CDOM optical properties of the river (P<0.01), while DOC, TSM, and Tur had a great influence on the CDOM optical properties of lakes (P<0.01). There was a strong correlation between pH and CDOM in the saline lakes, while DOC was significantly correlated with CDOM in the freshwater lakes (P<0.05). |
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