Biological and photochemical transformations of amino acids and lignin phenols in riverine dissolved organic matter
Biological and photochemical transformations of amino acids and lignin phenols in riverine dissolved organic matter
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DOI：
10.1007/s10533-010-9435-4
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发表时间：
2011-01-01
期刊：
影响因子：
4
通讯作者：
Kaiser, Karl
中科院分区：
文献类型：
--
作者：
Benner, Ronald;Kaiser, Karl
光和生物降解的溶解有机物（DOM）在水中从布罗德河进行了研究，在实验室实验中使用太阳模拟器来控制强度和暴露的样品照射。水样中含有大量的微生物，每天对样品的照射量各不相同，以区分光化学降解和生物降解的相对贡献。通过对水体中溶解有机碳（DOC）浓度和DOM中的有色DOM（CDOM）、木质素酚类和氨基酸等特定组分的监测，研究了这些DOM组分的降解反应性和主要途径。生物降解是主要负责的DOC和损失的氨基酸组分的DOM的整体的反硝化，而光降解是主要负责的DOM的发色团和木质素酚组分的损失。木质素酚类化合物的光降解速率受芳环上甲氧基的影响很大。丁香基（S）酚具有两个甲氧基取代，香草基（V）酚具有一个甲氧基取代，并且对羟基（P）酚未被甲氧基取代。光化学衰减常数以S酚最高，P酚最低，并遵循一致的模式（S > V > P）。氨基酸和木质素酚的碳归一化产率被认为是有用的分子指标的高活性（即不稳定）的可生物降解和光降解DOM的组件，分别。
The photo- and bio-degradation of dissolved organic matter (DOM) in water from the Broad River were investigated in laboratory experiments using a solar simulator to control the intensity and exposure of samples to irradiation. The water samples included a natural assemblage of microorganisms, and the daily exposure of samples to irradiation was varied to distinguish the relative contributions of photochemical and biological degradation. Concentrations of dissolved organic carbon (DOC) and specific components of DOM, including chromophoric DOM (CDOM), lignin phenols and amino acids, were monitored to investigate the reactivity and predominant pathway of degradation of these DOM components. Biodegradation was primarily responsible for the overall remineralization of DOC and losses of the amino acid component of DOM, whereas photodegradation was primarily responsible for losses of the chromophoric and lignin phenol components of DOM. The rates of photodegradation of lignin phenols were strongly influenced by the presence of methoxy groups on the aryl ring. Syringyl (S) phenols have two methoxy substitutions, vanillyl (V) phenols have one methoxy substitution, and p-hydroxy (P) phenols are not substituted with methoxy groups. Photochemical decay constants were highest for S phenols, lowest for P phenols and followed a consistent pattern (S > V > P) in the experiments. The carbon-normalized yields of amino acids and lignin phenols were found to be useful molecular indicators of the highly reactive (i.e. labile) components of biodegradable and photodegradable DOM, respectively.