Effect of humic substance photodegradation on bacterial growth and respiration in lake water
Effect of humic substance photodegradation on bacterial growth and respiration in lake water
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DOI：
10.1128/aem.71.10.6267-6275.2005
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发表时间：
2005-10-01
影响因子：
4.4
通讯作者：
Mopper, K
中科院分区：
文献类型：
--
作者：
Anesio, AM;Granéli, W;Mopper, K
这项研究探讨了腐殖质 (HS) 的化学成分和光反应性如何影响湖水中的细菌生长、呼吸和生长效率 (BGE)。将来自不同水生环境的代表不同溶解有机物来源（本地和外来）的 HS 水溶液暴露于人工太阳紫外线辐射下。将这些溶液添加到通过 0.7 微米孔径过滤器（含有无食草湖细菌）的湖水中，然后黑暗孵育 5、43 和 65 小时。对于 5 小时的孵育，几种受辐射的 HS 抑制细菌碳生成 (BCP)，并且这种抑制与 H2O2 光生成高度相关。 H2O2 在黑暗中衰减，43 小时后，几乎所有受辐射的 HS 都增强了 BCP（相对于未受辐射的对照，平均增加 39%，标准误差 = 7.5%，n = 16）。 HS 的紫外线暴露也会增加细菌呼吸（增加约 18%，标准误差 = 5%，n = 4），但小于 BCP，导致 BGE 平均增加 32%（标准误差 = 10%，n = 4）。 BCP 的光增强与 HS 的本体特性（即元素和化学成分）无关。然而，当 BCP 的光增强标准化为吸光度时，出现了 HS 来源和提取方法的几种趋势。吸光度归一化的亲水酸和腐殖酸样品比疏水酸和黄腐酸样品显示出更大的 BCP 增强作用。此外，吸光度归一化的本地样品显示 BCP 增强程度比异源样品高 10 倍，表明前者是生物底物更有效的光生产者。
This study addresses how humic substance (HS) chemical composition and photoreactivity affect bacterial growth, respiration, and growth efficiency (BGE) in lake water. Aqueous solutions of HSs from diverse aquatic environments representing different dissolved organic matter sources (autochthonous and allochthonous) were exposed to artificial solar UV radiation. These solutions were added to lake water passed through a 0.7-mu m-pore-size filter (containing grazer-free lake bacteria) followed by dark incubation for 5, 43, and 65 h. For the 5-h incubation, several irradiated HSs inhibited bacterial carbon production (BCP) and this inhibition was highly correlated with H2O2 photoproduction. The H2O2 decayed in the dark, and after 43 h, nearly all irradiated HSs enhanced BCP (average 39% increase relative to nonirradiated controls, standard error = 7.5%, n = 16). UV exposure of HSs also increased bacterial respiration (by similar to 18%, standard error = 5%, n = 4), but less than BCP, resulting in an average increase in BGE of 32% (standard error = 10%, n = 4). Photoenhancement of BCP did not correlate to HS bulk properties (i.e., elemental and chemical composition). However, when the photoenhancement of BCP was normalized to absorbance, several trends with HS origin and extraction method emerged. Absorbance-normalized hydrophilic acid and humic acid samples showed greater enhancement of BCP than hydrophobic acid and fulvic acid samples. Furthermore, absorbance-normalized autochthonous samples showed similar to 10-fold greater enhancement of BCP than allochthonous-dominated samples, indicating that the former are more efficient photoproducers of biological substrates.