水生植物凋落物来源溶解有机质的光降解和生物降解的组成差异：活性氧对难降解组分的作用。
The composition difference of macrophyte litter-derived dissolved organic matter by photodegradation and biodegradation: Role of reactive oxygen species on refractory component.
机构信息
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China.
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China.
出版信息
Chemosphere. 2020 Mar;242:125155. doi: 10.1016/j.chemosphere.2019.125155. Epub 2019 Oct 21.
The overgrowth of macrophytes has become serious due to increasing eutrophication in shallow lakes. The primary degradation processes of macrophytes litter, including photodegradation and biodegradation, induce considerable patchiness in the concentration and bioavailability of dissolved organic matter (DOM). In this study we investigated the composition evolution of DOM derived from emergent aquatic plant litter, Phragmites australis, in microbial degradation, photodegradation, and the combination of bio- and photo-degradation. Results revealed that the effects of photo- and biodegradation on the composition difference of macrophyte litter-derived DOM during short- and long-term degradation phase were different. Although large changes in DOM were observed after five days of incubation, the abundance and chemical composition were similar in the three treatments. However, more concentration of DOM was produced by combined photo- and biodegradation at the long-term degradation phase, and the composition of DOM showed less lignin-like formulae, as well as less condensed aromatic and aromatic compounds when compared to sole treatments. More reactive oxygen species (ROS) were found under the combined treatments, thus the contents of refractory components (condensed aromatic- and aromatic compound groups) were reduced. This study provide deeper insight into the fate of DOM and relevant biogeochemical processes in eutrophic lakes.
由于浅水湖中富营养化的加剧，大型水生植物的过度生长变得严重。大型水生植物凋落物的主要降解过程，包括光降解和生物降解，会导致溶解有机物质（DOM）的浓度和生物可利用性出现相当大的不均匀性。在这项研究中，我们调查了来自挺水植物凋落物，芦苇（Phragmites australis）的 DOM 在微生物降解、光降解以及生物和光降解组合中的组成演变。结果表明，在短期和长期降解阶段，光降解和生物降解对大型水生植物凋落物源 DOM 的组成差异的影响是不同的。尽管在孵育五天后观察到 DOM 发生了很大变化，但在三种处理方式下，DOM 的丰度和化学组成相似。然而，在长期降解阶段，联合光生物降解会产生更多的 DOM，与单一处理相比，DOM 的组成显示出较少的木质素类似结构，以及较少的浓缩芳香族和芳香族化合物。在联合处理下发现了更多的活性氧（ROS），因此，难降解成分（浓缩芳香族和芳香族化合物组）的含量减少。本研究深入了解了富营养化湖泊中 DOM 的命运和相关生物地球化学过程。
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