Ciliated protozoans are important constituents of periphytic communities in aquatic habitats, including river-floodplain ecosystems. As the knowledge about the diversity and ecological importance of periphytic ciliates in floodplain habitats is still limited, the main objectives of this study were to analyse the temporal variations in the community structure and functional role and reveal the main environmental factors controlling community dynamics. The study was conducted in one of the Danube's largest conserved floodplains – Kopački Rit in Croatia. In situ research included two experimental series in a lake, the first from spring till winter and the second from summer till winter. Samples were collected biweekly using glass slides as artificial substrates for periphyton development. During the study, two hydrological (low-water and high-water) periods interchanged. High-water periods were characterized by greater water transparency and nutrient concentrations, while electrical conductivity, chlorophyll a concentration, total suspended solids and particulate organic matter in water were higher during low-water periods. Furthermore, hydrological changes greatly affected the periphytic ciliate communities and the highest abundances were registered during low water levels. We identified a total of 133 ciliate taxa, among which the peritrichs, sessile filter feeders, were the dominant representatives in the periphyton, with the highest densities registered in the absence of floods. During extremely high water levels, the composition of the ciliate community in periphyton changed, with mobile ciliates, predators and filter feeders, becoming dominant. This study indicates that the main food source for periphytic ciliates in a floodplain lake are bacteria and algae, confirming the important role of these microorganisms in the lake food web, by making the carbon fixed in bacteria and algae available for the organisms of higher trophic levels. Additionally, periphytic ciliates have a considerable effect on planktonic organisms in the lake, thus connecting benthic and pelagic food webs, especially during low-water periods.

纤毛原生动物是水生生境包括河洪平原生态系统中周围生植物群落的重要组成部分。由于对洪泛区生境中附生纤毛虫的多样性和生态重要性的认识仍然有限，因此本研究的主要目的是分析群落结构的时间变化和功能作用，并揭示控制群落动态的主要环境因素。这项研究是在多瑙河最大的自然保护区之一-克罗地亚的KopačkiRit中进行的。原位研究包括在一个湖泊中进行的两个实验系列，第一个从春季到冬季，第二个从夏季到冬季。每两周使用载玻片作为周生植物发育的人工基质收集样品。在研究过程中，两个水文（低水位和高水位）时期互换了。高水期的特点是水的透明度和养分浓度更高，而电导率，叶绿素a在低水时期，水中的总浓度，总悬浮固体和颗粒状有机物较高。此外，水文变化极大地影响了周围的纤毛虫群落，并且在水位较低时记录的丰度最高。我们确定了总共133个纤毛类群，其中蠕虫，无柄滤食器是围生植物的主要代表，在没有洪水的情况下密度最高。在极高的水位期间，附生植物纤毛虫群落的组成发生了变化，活动纤毛虫，捕食者和滤食性动物逐渐占优势。这项研究表明，洪泛区湖泊中附生纤毛虫的主要食物来源是细菌和藻类，这证实了这些微生物在湖泊食物网中的重要作用，通过将碳固定在细菌和藻类中来提供更高营养水平的生物。此外，周生的纤毛虫对湖中的浮游生物具有相当大的影响，因此可以连接底栖和上层食物网，尤其是在水位低的时期。