溶解性有机质(DOM)在元素的生物地球化学循环和森林生态系统功能的调节中起着举足轻重的作用。然而,关于寒温带山地森林DOM的区域和季节特征的研究仍不全面。在这项研究中,水样,土壤,收集了森林流域不同地点的沉积物,它们的DOM具有激发-发射矩阵和平行因子分析(EEM-PARAFAC)的特征。结果表明,陆源腐殖质是所研究水库和流入河流中的主要DOM。DOM的质量和数量在地形和季风降水的影响下表现出时空变化。雨季溶解有机碳(DOC)平均浓度为11.62mg/L,高于旱季(8.18mg/L)。在雨季和上游水中观察到的腐殖质指数(HIX)值高于旱季和水库水。傅里叶变换离子回旋共振质谱(FTICR-MS)用于进一步发展对DOM原位降解过程的分子水平理解。结果表明,在自然条件下,光降解而不是生物降解可能在陆源腐殖质样物质的原位降解中起主导作用。原位降解后DOM的生物降解性增强。此外,原位降解后,观察到DOM中消毒剂副产物前体的显着减少。据我们所知,这是对来源的第一次研究,特点,以及寒温带森林水库中DOM的原位降解。这些发现有助于更好地了解质量,数量,研究水库中DOM的生物地球化学过程,可能有助于选择供水饮用水处理技术。
Dissolved organic matter (DOM) plays a pivotal role in the biogeochemical cycles of elements and the regulation of forest ecosystem functions. However, studies on the regional and seasonal characteristics of DOM in cold-temperate montane forests are still not comprehensive. In this
study, samples of water, soil, and sediment from different sites in the forest drainage basin were collected, and their DOM was characterized by an excitation-emission matrix and parallel factor analysis (EEM-PARAFAC). The results showed that terrestrial-sourced humic-like substances were the dominant DOM in the studied reservoir and inflowing rivers. The quality and quantity of DOM exhibited spatiotemporal variations with the influence of terrain and monsoonal precipitation. The average concentration of dissolved organic carbon (DOC) in the wet season was 11.62 mg/L, which was higher than that in the dry season (8.18 mg/L). Higher humification index (HIX) values were observed in the wet season and upstream water than in the dry season and reservoir water. Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) was used to further develop a molecular-level understanding of the in situ degradation process of DOM. The results indicated that
photodegradation rather than biodegradation may play a dominant role in the in situ degradation of terrestrial-sourced humic-like substances under natural conditions. The biodegradability of DOM was enhanced after the in situ degradation process. Additionally, a significant decrease in the precursors of disinfectant byproducts in DOM was observed after in situ degradation. To our knowledge, this is the first
study of the sources, characteristics, and in situ degradation of DOM in a reservoir in a cold-temperate forest. These findings help better understand the quality, quantity, and biogeochemical process of DOM in the studied reservoir and may contribute to the selection of drinking water treatment technologies for water supply.