Aerobic anoxygenic phototrophic (AAP) bacteria are a common component of freshwater microbial communities. They harvest light energy using bacteriochlorophyll a-containing reaction centers to supplement their predominantly heterotrophic metabolism. We used epifluorescence microscopy, HPLC, and infrared fluorometry to examine the dynamics of AAP bacteria in the mesotrophic lake Vlkov during the seasonal cycle. The mortality of AAP bacteria was estimated from diel changes of bacteriochlorophyll a fluorescence. The AAP abundance correlated with water temperature and DOC concentration. Its maximum was registered during late summer, when AAP bacteria made up 20% of total bacteria. The novel element of this study is the seasonal measurements of AAP mortality rates. The rates ranged between 1.15 and 4.56 per day with the maxima registered in early summer coinciding with the peak of primary production, which documents that AAP bacteria are a highly active component of freshwater microbial loop.

中文翻译：

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淡水湖Vlkov有氧产氧养分的季节动态。

好氧产氧营养型（AAP）细菌是淡水微生物群落的常见组成部分。他们使用含有细菌叶绿素a的反应中心收集光能，以补充其主要的异养代谢。我们使用了落射荧光显微镜，HPLC和红外荧光法来检查中营养湖Vlkov在季节性周期中AAP细菌的动态。根据细菌叶绿素a荧光的狄尔变化来估计AAP细菌的死亡率。AAP丰度与水温和DOC浓度相关。最高的记录是在夏末，当时AAP细菌占细菌总数的20％。这项研究的新颖之处在于AAP死亡率的季节性测量。比率介于1.15和4。