Contamination of freshwater habitats with microplastic is threatening particularly filter-feeders within the aquatic community. Using Daphnia magna and Daphnia pulex as models, the effects of food supply and temperature on the ingestion of polystyrene spheres (diameter 1 μm, concentration of 200 ng*ml-1) was analysed. The ingestion rates of microplastic beads were increased in conditions of low food and high temperatures, reflecting the complex regulation patterns of the water current generated by the animals' thoracic limbs. Maximal enrichment of 1160 times the concentration in the ambient medium was observed within one hour. Analyses of the impact of microplastic ingestion on physiological parameters used the carbohydrate concentration as an indicator for the animals' metabolic state. Exposure to the microplastic beads for three days in the presence or absence of Desmodesmus subspicatus did not affect the animals' glycogen reserves beyond the response to the prevailing food and temperature conditions. Projecting the insights from laboratory experiments to the habitat situation, increased burdens of microplastic particles can be expected in filtering zooplankton organisms in warm water and scarce supply of food, like the clear-water phase of lakes in the summer.

中文翻译：

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水蚤中的微塑料负荷因温度升高而加剧

微塑料对淡水栖息地的污染尤其威胁着水生社区内的滤食动物。以大溞和大溞为模型，分析了食物供应和温度对聚苯乙烯球（直径1 μm，浓度200 ng*ml-1）摄入的影响。微塑料珠的摄入率在低食物和高温条件下增加，反映了动物胸肢产生的水流的复杂调节模式。在一小时内观察到的最大富集是环境培养基中浓度的 1160 倍。微塑料摄入对生理参数影响的分析使用碳水化合物浓度作为动物代谢状态的指标。在存在或不存在 Desmodesmus subspicatus 的情况下暴露于微塑料珠三天不会影响动物的糖原储备，超出对普遍食物和温度条件的反应。将实验室实验的见解投射到栖息地情况，预计在过滤温水中的浮游动物生物和食物供应稀缺（如夏季湖泊的清水阶段）时，微塑料颗粒的负担会增加。