Section of Soil Fauna Ecology and Ecotoxicology, Department of Bioscience, Aarhus University, Vejlsøvej 25, 8600 Silkeborg, Denmark; College of Resources and Environment, Southwest University, Chongqing 400716, China; Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
Section of Soil Fauna Ecology and Ecotoxicology, Department of Bioscience, Aarhus University, Vejlsøvej 25, 8600 Silkeborg, Denmark.
Environ Pollut. 2019 Nov;254(Pt B):113071. doi: 10.1016/j.envpol.2019.113071. Epub 2019 Aug 19.
Climatic stressors and chemicals should not be treated as isolated problems since they often occur simultaneously, and their combined effects must be evaluated including their possible interactive effects. In the present study we subjected springtails (Folsomia candida) to combined exposure to phenanthrene and dynamic heat cycles in a full factorial experiment. In a microcosm experiment, we studied the population growth of springtails subjected to a range of sub-lethal concentrations of phenanthrene. During the 28-day experiment we further subjected microcosms to varying numbers of repeated dynamic heat cycles (0-5 cycles) simulating repeated heat waves. We found a synergistic interaction between the effects of phenanthrene and the number of heat waves on both body mass of adults and juvenile production of F. candida showing that the negative effects of phenanthrene were intensified when animals were heat stressed, and/or vice versa. This interaction was not related to internal concentrations of phenanthrene in adult springtails, nor was it due to altered degradation of phenanthrene in soil. We argue that both phenanthrene (by its partitioning into membrane bilayers) and heat have detrimental effects on the physical conditions of cellular membranes in a dose-dependent manner, which, under extreme circumstances, can increase membrane fluidity to a level which is sub-optimal for normal membrane functioning. We discuss the possibility that the synergistic interactions subsequently reduce life-history parameters such as growth and reproduction.
气候压力源和化学物质不应该被视为孤立的问题，因为它们经常同时发生，必须评估它们的综合影响，包括它们可能的交互作用。在本研究中，我们在完全析因实验中使跳虫（Folsomia candida）同时暴露于菲和动态热循环中。在一个微宇宙实验中，我们研究了一系列亚致死浓度菲暴露下跳虫种群增长的情况。在 28 天的实验中，我们进一步对微宇宙施加了不同数量的重复动态热循环（0-5 个循环），模拟了反复的热浪。我们发现菲和热波数量对成虫体重和 F. candida 幼体产量的影响存在协同作用，表明当动物受到热胁迫时，菲的负面影响加剧，反之亦然。这种相互作用与成年跳虫体内菲的浓度无关，也不是由于土壤中菲的降解发生改变所致。我们认为，菲（通过分配到膜双层中）和热都以剂量依赖的方式对细胞膜的物理条件产生有害影响，在极端情况下，这会增加细胞膜的流动性，使其低于正常膜功能的最佳水平。我们讨论了协同作用随后降低生长和繁殖等生活史参数的可能性。
