| 不同淹水环境下湖泊沉积物DOM的特征与来源 |
| 摘要点击 1857 全文点击 525 投稿时间：2021-12-08 修订日期：2022-01-18 |
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| 中文关键词 溶解性有机质(DOM) 常年淹水区 季节淹水区 来源 沉积物 人类活动 |
| 英文关键词 dissolved organic matter (DOM) perennial inundation zone seasonal inundation zone source sediment human activities |
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| 中文摘要 |
| 为揭示水位的空间差异对于湖泊沉积物溶解性有机质（DOM）特性的影响与作用途径，采用紫外可见光谱（UV-Vis）和三维荧光光谱结合平行因子分析（EEM-PARAFAC），探究东洞庭湖不同淹水环境对沉积物DOM的组成与来源的影响.结果表明，DOM中类蛋白组分［类色氨酸C2与类酪氨酸C3，（72.95±8.94）%］高于类腐殖酸组分［C1，（27.05±8.94）%］.季节淹水下DOM具有更高的类蛋白组分和更低的类腐殖酸组分，而常年淹水下的DOM芳香性（SUVA254）与疏水组分（SUVA260）更高，在空间上表现为：湖中段>入湖段>出湖段，更有利于污染物迁移.通过对荧光参数FI （1.93）、BIX （0.91）和HIX （1.57）的计算发现，沉积物DOM具有内源为主和陆源较弱的混合特征.这可能受到人为输入与沉积物特性影响，季节淹水区沉积物裸露增强污水排放的直接作用，且黏粒和总氮（TN）含量与FI呈显著正相关，说明沉积物高营养成分和黏粒含量影响DOM的内源成分（FI>1.9）；而常年淹水区具有外来径流输入，pH和C/N与HIX和C1呈显著正相关，说明沉积物DOM由于常年淹水的碱性环境（pH>7.5）和径流输入比季节淹水区具有更高的陆源成分（HIX=1.38±0.57）.上述结果有助于揭示湖泊水文与人类活动过程中沉积物DOM对水质与污染响应的相关理论，为沉积物污染防治提供科学依据. |
| 英文摘要 |
| The characteristics and sources of DOM in sediments are significantly affected by fluctuations in lake water levels. However, the impact of spatial differences on water levels remain unclear. Here, 36 sediment samples were collected from the flood passage and coastal beach of East Dongting Lake. The differences in the composition and source of DOM in sediments under perennial inundation and seasonal inundation were studied using UV-visible absorbance (UV-Vis) and fluorescent excitation-emission matrix (EEM)-parallel factor analysis (PARAFAC). Three fluorescent components of DOM in the sediment were identified. The relative abundance of protein-like components was as high as (72.95±8.94)%, including tryptophan (C2) and tyrosine (C3). However, the humic-like component (C1) abundance was (27.05±8.94)%. Compared with that in perennial inundation, DOM in seasonal inundation had a higher and lower relative abundance of protein-like components and humic-like components, respectively. Further, the aromatic and hydrophobic components were higher in perennial inundation, showing a spatial pattern of the middle>entrance>outlet of the lake, which was more conducive to the migration of pollutants. The high FI (1.93) and BIX (0.91) and low HIX (1.57) indicated that the DOM in sediments had the mixed characteristics of being mainly endogenic and relatively weakly terrigenous. This was mainly influenced by human input and sediment characteristics. The direct effect of sewage discharge was intensified by sediment exposure in the seasonal inundation zone. Additionally, the contents of clay and total nitrogen (TN) were significantly positively correlated with FI, indicating that high nutrients and clay in sediments enhanced the endogenous input of DOM (FI>1.9). The perennial inundation zone was influenced by external runoff input. At the same time, the pH and C/N were significantly positively correlated with HIX and C1, indicating that DOM in the sediments had higher terrigenic characteristics (HIX=1.38±0.57) than those in the seasonal inundation zone owing to the alkaline environment (pH>7.5) and runoff input. The results above revealed the relevant theories of the response of DOM in sediment to water quality and pollution in the process of hydrology and human activities and provide a scientific basis for the prevention and control of sediment pollution in lakes. |
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