Compositional changes of dissolved organic carbon during its dynamic desorption from hyporheic zone sediments
Compositional changes of dissolved organic carbon during its dynamic desorption from hyporheic zone sediments
复制标题
潜流带沉积物动态解吸过程中溶解有机碳的组成变化
DOI：
10.1016/j.scitotenv.2018.12.189
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发表时间：
2019
影响因子：
9.8
通讯作者：
Tfaily Malak M
中科院分区：
文献类型：
--
作者：
Zhou Chenxin;Liu Yunde;Liu Chongxuan;Liu Yuanyuan;Tfaily Malak M
溶解有机物(DOM)是生物地球化学反应的重要驱动力，影响微生物群落功能，调节环境中孔隙水化学成分和氧化还原性质的变化。利用傅里叶变换离子回旋共振质谱仪(FTICR-MS)研究了DOM分子组成在有机质(OM)从HZ沉积物剥离过程中的变化。扩散传质和微生物降解是控制底泥中有机物释放速率和分子组成变化的两个主要过程。扩散传质过程限制了有机物从沉积物中的释放速率，但对释放的有机物的分子特征影响不大。另一方面，微生物降解优先消耗DOM的蛋白质和类脂部分，其特征是较低的碳标称氧化态(NOSC)、较低的分子量和较高的化学键饱和度。研究结果对河流水系中重要的临界区--潜流带的有机碳动态及相关微生物活动和污染物转化具有重要意义。
Dissolved organic matter (DOM) is an important driver for biogeochemical reactions that affect microbial community function, and regulate changes in porewater chemical composition and redox properties in the environment. This study investigated the variation in DOM molecular composition during the detachment of organic matter (OM) from hyporheic zone (HZ) sediments using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS). Diffusive mass transfer and microbial degradation were the two primary processes controlling the rate of OM release and molecular composition changes during the detachment from sediments. The diffusive mass transfer process limited the rate of OM release from the sediments, but had negligible effect on the molecular signature of the released OM. Microbial degradation on the other hand preferentially consumed the protein- and lipid-like fractions of the DOM, characterized by lower nominal oxidation states of carbon (NOSC), lower molecular weight, and a higher saturation of chemical bonds. The results have strong implication to the organic carbon dynamics and related microbial activities and contaminant transformation in hyporheic zones, an important critical area in river systems.