Marine Environmental Laboratory, Shenzhen Research Institute, The Hong Kong University of Science and Technology, Shenzhen, 518000, China; Department of Ocean Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China.
Environ Pollut. 2018 Dec;243(Pt B):1528-1538. doi: 10.1016/j.envpol.2018.09.119. Epub 2018 Sep 29.
In the present study, we characterized the sources of dissolved organic matter (DOM) and the processes controlling the evolution of DOM in a large anthropogenically perturbed estuary in Southern China. Three-dimensional excitation emission matrices (3D EEMs) revealed that DOM in the estuary was primarily from autochthonous origin although terrestrial sources also contributed to the DOM production. Parallel factor analysis (PARAFAC) of the EEMs dataset indicated that DOM in the estuary was a legacy from the upstream wastewater discharging activities, and estuarine mixing was the primary mechanism responsible for the decreasing concentrations of DOM components. However, non-conservative behavior of DOM components was also observed along the center transect as a result of additional removal process and spatial heterogeneity in the distribution of DOM. Seasonal influence on the concentrations and compositions of colloidal DOM in the estuary was also found. Asymmetric flow field-flow fractionation (AF4) analysis showed distinct distribution patterns of the colloidal DOM during the dry and wet seasons. Behavior of colloidal DOM was size-independent and the distribution of colloidal DOM was controlled by multiple depletion and replenishment cycles in the dry season, in contrast to those observed in the wet season. By combining both EEMs-PARAFAC modeling and AF4 technique, this study provided important information on the sources and fate of bulk and colloidal DOM in a large estuary with intensive anthropogenic influences.
在本研究中，我们描述了溶解有机物（DOM）的来源和控制 DOM 演化的过程，该研究地点为中国南方一个受到强烈人为干扰的大型河口。三维激发发射矩阵（3D EEMs）表明，尽管陆源物质也有助于 DOM 的产生，但河口的 DOM 主要来自于自生来源。EEMs 数据集的平行因子分析（PARAFAC）表明，河口的 DOM 是上游污水排放活动的遗留物，而河口混合是导致 DOM 成分浓度降低的主要机制。然而，由于 DOM 分布的空间异质性和额外的去除过程，在中心断面也观察到了 DOM 成分的非保守行为。河口胶体 DOM 浓度和组成的季节性影响也被发现。不对称流场流分离（AF4）分析显示，在干湿两季胶体 DOM 存在明显的分布模式。胶体 DOM 的行为与粒径无关，在旱季，胶体 DOM 的分布受多个消耗和补充循环的控制，而在雨季则没有观察到这种情况。本研究结合 EEMs-PARAFAC 模型和 AF4 技术，提供了关于一个受到强烈人为影响的大型河口的大量和胶体 DOM 的来源和归宿的重要信息。
