Department of Physics, University of Girona, 17003, Girona, Spain.
Department of Physics, University of Girona, 17003, Girona, Spain.
Environ Pollut. 2020 Dec;267:115439. doi: 10.1016/j.envpol.2020.115439. Epub 2020 Aug 20.
Daphnids, including the water flea Daphnia magna, can be exploited for wastewater treatment purposes, given that they are filter feeder organisms that are able to remove suspended particles from water. The presence of pollutants, such as microplastics and chemicals, might be considered stressors and modify the behaviour and survival of D. magna individuals. The impact of the cumulative pollutants that regulate the fate of living organisms has yet to be fully determined. Here we present the effect of double and triple combinations of stressors on the behaviour of D. magna. The impact of water temperature, ammonium and polystyrene microplastics on the filtration capacity and survival of D. magna is studied. Water temperatures of 15 °C, 20 °C and 25 °C, microplastic-to-food ratios of 25% and 75%, and ammonium concentrations of 10 and 30 mg N-NH L are tested after making dual and triple combinations of the parameters. A synergistic effect between water temperature and ammonium is normally observed but not in the case of the lower values of ammonium concentration and temperature. The combination of three stressors (water temperature, microplastics and ammonium) is also found to be synergistic, producing the greatest impact on D. magna filtration capacity and reducing their survival. In comparison with the effect of the two stressor conditions, the combination of the three stressors caused a reduction of between 13.1% and 91.7% in the t time (the time required for a 50% reduction in the D. magna filtration capacity) and a reduction of between 4.8% and 54.5% in TD50 (the time for 50% mortality).
水蚤，包括大型溞（Daphnia magna），可用于废水处理，因为它们是滤食性生物，能够从水中去除悬浮颗粒。污染物（如微塑料和化学物质）的存在可能被视为胁迫因素，改变大型溞个体的行为和生存。调节生物命运的累积污染物的影响尚未完全确定。在这里，我们展示了双重和三重胁迫组合对大型溞行为的影响。研究了水温、铵和聚苯乙烯微塑料对大型溞过滤能力和生存的影响。测试了 15°C、20°C 和 25°C 的水温、微塑料与食物比例为 25%和 75%、10 和 30 mg N-NH L 的铵浓度，然后对这些参数进行双重和三重组合。通常观察到水温和铵之间存在协同作用，但在较低的铵浓度和温度下则不然。还发现三种胁迫因素（水温、微塑料和铵）的组合也是协同的，对大型溞过滤能力的影响最大，降低了它们的存活率。与两种胁迫条件的影响相比，三种胁迫因素的组合导致 t 时间（大型溞过滤能力降低 50%所需的时间）减少了 13.1%至 91.7%，TD50（死亡率达到 50%所需的时间）减少了 4.8%至 54.5%。
