两个水库型湖泊中溶解性有机质三维荧光特征差异

应用三维荧光光谱技术(3D-EEM),研究了两个典型水库型湖泊(长寿湖和大洪海)水体中溶解性有机质(DOM)的荧光光谱特征,结合沿岸生态系统差异,讨论其对两个湖泊中DOM性质及来源的影响.结果表明,沿岸生态系统的差异性(尤其是人为干扰)是导致两个水体DOM地球化学特征存在明显差异的重要原因.两湖水体中DOM均存在4个荧光峰,且长寿湖样本中类蛋白物质含量更高;而大洪海水体中腐殖化程度较高的组分(C峰)含量较高.相关性分析表明,两湖DOM样本中类蛋白和类腐殖组分来源不同,而A、C峰代表的类腐殖组分存在共源性.通过荧光参数分析显示,沿岸以森林系统为主的大洪海水体DOM陆源性更强,腐殖化程度高;而长寿湖受两岸农田、果园的输入以及人为排放影响,其水体DOM具有明显的自生源特征,新生DOM含量较高,其荧光特征也反映了该区域水体受人为干扰较大.与其他不同湖泊对比,进一步表明沿岸生态系统类型及人为土地利用是决定水体DOM来源和特性的关键因素.

Three-dimensional fluorescence characteristic differences of dissolved organic matter (DOM) from two typical reservoirs

Three-dimensional (3D) excitation emission matrix (EEM) fluorescence spectroscopy was used to investigate the characteristics of dissolved organic matter (DOM) in two typical reservoirs, Changshou Lake and Dahonghai Lake. Characteristics of DOM were analyzed in view of the riparian ecosystems, which was the predominant cause of variance and the source of DOM in the reservoirs. The difference between two riparian ecosystems was significant due to anthropogenic impacts. Four fluorescent peaks were seen in DOM from both lakes. More protein-like components were observed in Changshou Lake, while more of the high-humic component (peak C) was seen in Dahonghai Lake. Additionally, correlation analysis suggested different sources for the protein-like and humic-like components. However, the two humic-like components (peak A and peak C) were from similar sources. Furthermore, specific fluorescence parameters indicated a higher degree of humification and allochthonous (terrigenous) DOM in Dahonghai, where riparian ecosystem was dominated by forest environment. DOM in Changshou Lake was significantly autochthonous (authigenic) and fresh because of human impacts in the riparian ecosystem such as agricultural runoff from farms and orchards. Comparison of the fluorescence characteristics with historical references confirmed that riparian ecosystems, and especially land uses related to human activities were important factors in the DOM characteristics of adjacent aquatic environments.