Abstract.A short overview of currently available studies on the ecology of viruses in running waters is provided. Additionally, a survey was conducted on the dynamics of both viruses and bacteria in an isolated floodplain segment of the Danube River and in the main channel near Vienna (Austria) during the hydrologically most dynamic phase (spring – summer). The study evaluates the differences between the main channel and the floodplain segment for suspended particle abundance and quality in relation to bacterial and viral parameters; both free-living forms and those attached to particles are examined. The hydrological disconnection of these two contrasting sampling sites influenced particle abundance and quality as well as the distribution of free-living vs. attached bacteria and viruses. The per-cell activity of bacteria attached to particles was significantly higher than that of the free-living fraction, particularly in the isolated water body. The abundance of bacteria and viruses on particles depended on particle quality (size). In the main channel, bacteria were significantly more abundant on surfaces (per mm2) of suspended matter > 5 μm (aggregates with organic constituents) compared to particles < 5 μm (mostly mineral grains). In the isolated water body, both bacteria and viruses were more abundant on the larger particles/aggregates. Data from both locations revealed a positive correlation between abundance of particles > 5μm and attached viruses; free-living viruses were less abundant at high > 5μm particle loads. Only in the isolated floodplain section was viral abundance positively influenced by elevated per-cell productivity of potential host bacteria. The results demonstrate that system variability on a relatively small topographical scale (within a river-floodplain system) has consequences for microbial life, including viruses.

中文翻译：

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多瑙河（奥地利）回水和主河道地点的病毒、细菌和悬浮颗粒

摘要：简要概述了目前关于流水中病毒生态学的研究。此外，在水文最活跃的阶段（春夏），对多瑙河一个孤立的洪泛区段和维也纳​​（奥地利）附近的主要航道中的病毒和细菌的动态进行了调查。该研究评估了与细菌和病毒参数相关的悬浮颗粒丰度和质量的主河道和洪泛区段之间的差异；对自由生活形式和附着在粒子上的形式都进行了检查。这两个对比采样点的水文断开影响了粒子的丰度和质量，以及自由生活与附着的细菌和病毒的分布。附着在颗粒上的细菌的每细胞活性明显高于自由生活部分，特别是在孤立的水体中。颗粒上细菌和病毒的丰度取决于颗粒质量（大小）。在主通道中，与小于 5 μm 的颗粒（主要是矿物颗粒）相比，在大于 5 μm 的悬浮物质（与有机成分的聚集体）的表面（每平方毫米）上的细菌数量明显更多。在孤立的水体中，细菌和病毒在较大的颗粒/聚集体上更为丰富。来自这两个位置的数据显示，大于 5μm 的颗粒丰度与附着的病毒呈正相关；在大于 5μm 的颗粒负载下，自由生活的病毒数量较少。只有在孤立的洪泛区部分，病毒丰度才受到潜在宿主细菌单细胞生产力提高的积极影响。结果表明，相对较小的地形尺度（河流-泛滥平原系统内）的系统变异性会对包括病毒在内的微生物生命产生影响。