Photochemical transformation of dissolved organic matter in lakes
Photochemical transformation of dissolved organic matter in lakes
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DOI：
10.4319/lo.2000.45.4.0753
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发表时间：
2000-06-01
影响因子：
4.5
通讯作者：
Tranvik, LJ
中科院分区：
文献类型：
--
作者：
Bertilsson, S;Tranvik, LJ
在湖水中溶解的有机物（DOM）的光化学转化的调查，我们发现溶解的无机碳（DIC）和低分子量的羧酸（草酸，丙二酸，甲酸，乙酸）的光化学生产，模拟太阳紫外线（UV）辐射暴露的过滤器消毒的地表水从38个调查湖泊。鉴于水化学的研究系统的大的变化，我们认为，这些光产品普遍产生在阳光照射的湖水。测得的羧酸碳的产生相当于所产生DIC的34.4%（中值）。DIC和羧酸的生产过程中，8小时的温和的紫外线照射对应的总溶解的有机碳池的平均4.7%（SD 2.9）。因此，光化学降解可能是湖泊表层DOM的主要汇。所有的光反应速率都与在紫外线照射过程中吸收的总辐射量密切相关（r（2）> 0.8），这主要取决于水中有色DOM的量。吸收辐射能量标准化后DIC产生的变化可能部分归因于一般水化学参数（例如，pH、铁浓度、电导率）。
In a survey of photochemical transformation of dissolved organic matter (DOM) in lake water, we found photochemical production of dissolved inorganic carbon (DIC) and low molecular weight carboxylic acids (oxalic, malonic, formic, and acetic acid), upon simulated solar ultraviolet (UV) radiation exposure of filter-sterilized surface water from 38 investigated lakes. Given the large variability in water chemistry of the studied systems, we suggest that these photoproducts are universally produced in sunlight exposed lake water. The measured production of carboxylic acid carbon corresponded to 34.4% (median) of the produced DIC. The production of DIC and carboxylic acids during 8 h of mild UV irradiation corresponded to an average of 4.7% (SD 2.9) of the total dissolved organic carbon pool. Hence, photochemical degradation could be a major sink for DOM in the surface layer of lakes. All photoreaction rates were strongly correlated to the total radiation absorbed during UV exposure (r(2) > 0.8), which depends mainly on amount of colored DOM in the water. The variability in DIC production after normalizing for absorbed radiation energy could partly be attributed to general water chemistry parameters (e.g., pH, iron concentration, conductivity).