白洋淀沉积物间隙水中的自然有机质结构特征

Characteristic of Structure of Natural Organic Matter in Pore Water of Sediment in Baiyangdian Lake

利用紫外-可见吸收光谱（UV-Vis）研究白洋淀沉积物间隙水中的自然有机质（NOM）的结构和来源，通过提取自然有机质的Uv-vis图谱特征参数（HIX）发现，与入河口区和水产养殖区的采样点相比，淀区出水口区域采样点的沉积物间隙水中的自然有机质腐殖化程度较高，这表明淀区出水口区域沉积物间隙水中的自然有机质具有较高的芳香碳的结构。白洋淀沉积物间隙水中的自然有机质分层分析结果显示，表层沉积物（0～3cm深）间隙水中的自然有机质腐殖化程度较低。特征参数E2/E3（UV-Vis在波长250nm和365nm处吸收率的比值）显示，白洋淀自然保护区采样点沉积物间隙水中的自然有机质主要来自胡敏酸源，河口区和养殖区采样点沉积物间隙水中的自然有机质主要来自生物源，其他采样点沉积物间隙水中的自然有机质则同时受到陆源和生物源的影响。

The origin and characteristics of natural organic matter（NOM） in the lake were studied using UV-vis- ible（UV-vis）. The Humification index（HIX）, deduced from the UV-vis of natural organic matter, showed that the humification degree of natural organic matter was higher in the lake outlet area than they were at the river estuary and aquaculture areas, indicating that the proportion of aromatic carbon structures might be greater in the former than in the later. The variation of HIX implied that the upper sediment pore water had a lower hu- mification degree, as well as less aromatic carbon atoms and unsaturated carbon structures than the substrate sediment pore water it was compared with. E2,/E3 demonstrated the aquatic reserve was the origin of humic ac- id in natural organic matter, and the river estuary and aquaculture areas were affected by autochthonous sourc- es, whereas the other areas were mainly affected by both autochthonous sources and allocthonous sources. This study provided scientific basis for monitoring aqueous natural organic matter in a macrophyte-dominated shallow lake that interfered strongly with human beings.