淡水生态系统溶解态和颗粒态有机质互转机制及其影响因素

The transformation between dissolved organic matter (DOM) and particulate organic matter (POM) plays a crucial role in the organic matter cycling, interactions with aquatic organisms, bioavailability of pollutants in freshwater ecosystems. The typical river (Huanghe River), Deep Lake (Guanting Reservoir), shallow lake (Chaohu Lake) and wetland (Baiyangdian Lake) are selected as the research objects. The multiple advanced technologies, including three-dimensional fluorescence, NMR, high-resolution mass spectrometry (e.g. FT-ICR-MS and TOF-MS), and isotope mass spectrometry, are employed. The characterization of the field samples and environmental factors analysis are conducted to explore constitution of mechanisms and potential influencing factors in different aquatic ecosystems. The conversion efficiency of various transformation mechanisms, including aggregation/dissolution, adsorption/desorption, light-induced transformation, and organisms’ involved transformation, are evaluated on the basis of laboratory experiments. And the key factors are also screened. Based on the thermodynamic theory a conceptual DOM-POM mutual transformation model will be developed to explain the effects of natural or man-made factor on the transformation, the DOM/POM status, and the potential contribution of organic matter to other media in various aquatic ecosystems. The research achievement can help to understand behavior and environmental effects of organic matter and its response to global climate changes in the aquatic ecosystems.

溶解态有机质（DOM）和颗粒态有机质（POM）的相互转化对淡水生态系统中有机质的循环、其与生物的相互作用及其对污染物的生物有效性具有重要的影响。本研究拟选择河流（黄河）、深水湖（官厅水库）、浅水湖（巢湖）和湿地（白洋淀）等淡水生态系统为对象，利用三维荧光、核磁共振、高分辨率质谱、同位素质谱等技术手段，通过野外样品表征和环境因子分析探究典型淡水生系统中DOM-POM转化过程的机制构成和潜在影响因子；以室内实验比较有机质参与聚集/溶解、吸附/解析、光诱导转化和生物参与转化等机制的转化效率，并筛选出关键影响因子，构建基于热力学理论的水生系统DOM-POM互相转化的概念模型，解释自然或人为因素对各转化机制的影响、不同相态有机质的组成差异性和对其他介质的潜在贡献等。其成果将丰富对水生系统中有机质的表生行为和环境效应及对全球气候变化响应的理论认知。

溶解态有机质（DOM）和颗粒态有机质（POM）的相互转化对淡水生态系统中有机质的循环、其与生物的相互作用及其对污染物的生物有效性具有重要的影响。本研究针对DOM-POM转化机制及其环境效应开展了如下工作：.（1）利用多种检测技术测定了巢湖水体中天然有机质的特征并解析它们潜在的来源，尝试揭示DOM与POM的相互转化过程。.（2）开发了第一代DOM-POM相互转化过程的多通量稳定光源、精确控温的模拟实验装置。.（3）估算了DOM与疏水性有机污染物（HOC）的结合常数，从官能团变化、微观折展和分子间结合能变化等角度分析了潜在的结合机制，以及判定了DOM-POM转化过程对DOM-HOC结合作用的影响。.（4）查明了DOM-POM受到光诱导激发产生活性氧物质，从而影响有机磷阻燃剂的降解过程。.（5）从宏观生态系统层面到微观分子机制层面揭示了DOM-POM相互转化机制， 并给出了基于exergy的DOM-POM相互转化的概念模型以及一般性数学模型。.上述工作将丰富对水生系统中天然有机质的表生行为和环境效应的理论认知。