As the submerged shoot parts of common reed (Phragmites australis) can provide large surfaces for biofilm‐forming bacteria, extensive reed stands can effectively contribute to the self‐purification in the littoral zones of freshwaters. However, bacterial biofilm developed on reed surfaces have been studied only in still waters. In the present study, comparative examinations were performed on the planktonic and reed biofilm bacterial communities from two different riverine water bodies. Water and reed biofilm samples were taken at the beginning and end of the vegetation period from (a) a regulated side arm and (b) a separated oxbow of River Danube. Besides measuring physical and chemical environmental variables, planktonic bacterial cell numbers were detected by 4′,6‐diamidino‐2‐phenylindole staining method, and the bacterial communities were compared by denaturing gradient gel electrophoresis. Our results demonstrated that the structure and composition of bacterial communities correlated with different environmental variables and were different regarding both the habitats (planktonic vs. reed biofilm) and the types of riverine water bodies. The seasonal differences in the bacterial community structures were smaller in the river side arm than in the separated oxbow. In the water column, representatives of widespread and typical freshwater planktonic bacteria (“Candidatus Planktophila,” Limnohabitans, and Polynucleobacter), whereas, in the reed biofilm samples, phototrophic and plant associated bacteria were identified.

中文翻译：

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多瑙河不同河水体中浮游生物和芦苇生物被膜细菌的比较

作为普通芦苇（芦苇）的浸没部分可以为形成生物膜的细菌提供较大的表面，广泛的芦苇林可以有效地促进淡水沿岸区域的自净。但是，仅在静水中才研究了芦苇表面上形成的细菌生物膜。在本研究中，对来自两个不同河流水体的浮游生物和芦苇生物膜细菌群落进行了比较检查。在植被期的开始和结束时，从（a）受调节的侧臂和（b）多瑙河的分开的牛弓采集水和芦苇生物膜样品。除了测量物理和化学环境变量外，还通过4'，6-二mid基-2-苯基吲哚染色法检测浮游细菌的细胞数，并通过变性梯度凝胶电泳比较细菌群落。我们的结果表明，细菌群落的结构和组成与不同的环境变量相关，并且在生境（浮游生物与芦苇生物膜）和河流水体类型方面都不同。河边的细菌群落结构的季节性差异小于分离的牛弓。在水栏中，代表着广泛而典型的淡水浮游细菌（“Candidatus Planktophila，Limnohabitans和Polynucleobacter），而在芦苇生物膜样品中，鉴定出光养细菌和植物相关细菌。