Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole, Dorset, BH12 5BB, UK; Department of Biosciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, Devon EX4 4QD, UK.
Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole, Dorset, BH12 5BB, UK.
Sci Total Environ. 2024 Oct 15;947:174566. doi: 10.1016/j.scitotenv.2024.174566. Epub 2024 Jul 8.
Microplastic exposure can cause a range of negative effects on the biochemistry, condition and ecology of freshwater fishes depending on aspects of the exposure and the exposed fish. However, fishes are typically exposed to microplastics and additional multiple stressors simultaneously, for which the combined effects are poorly understood and may have important management consequences. Additive effects are those where the combined effect is equal to the sum, antagonistic where combined effects are less than the sum and for synergistic effects the combined effect is greater to the sum of the individual effects. Here, we performed a meta-analysis of studies recording freshwater fish responses to microplastic-stressor exposures to test if interactions were primarily non-additive (synergistic or antagonistic), and factors impacting the net response. Individual responses were classified (antagonistic/additive/synergistic) and the fit of net responses to a null additive model determined for 838 responses (36 studies) split by categorical variables for the microplastic exposure (environmental relevance, interacting stressor, microplastic morphology and response category measured), as well as the exposed fish (lifestage, ecology and family). Most responses were classified as antagonistic (48 %) and additive (34 %), with synergistic effects least frequent (17 %). Net responses fitted null additive models for all levels of interacting stressor, fish family and microplastic morphology. In contrast, net antagonism was present for biochemical responses, embryo lifestages, environmentally relevant microplastic exposures and fish with benthopelagic ecology, while synergism was identified for fishes with demersal ecology. While substantial knowledge gaps remain and are discussed, the data thus far suggest microplastic-stressor responses in freshwater fishes are rarely synergistic and, therefore, addressing either or both stressors will likely result in positive management and biological outcomes.
微塑料暴露会对淡水鱼类的生物化学、状况和生态产生一系列负面影响，具体取决于暴露的方面和暴露的鱼类。然而，鱼类通常同时暴露于微塑料和其他多种胁迫因素下，对于这些综合效应，我们知之甚少，这可能会产生重要的管理后果。附加效应是指联合效应等于总和，拮抗效应是指联合效应小于总和，而协同效应是指联合效应大于各个效应的总和。在这里，我们对记录淡水鱼类对微塑料胁迫暴露反应的研究进行了荟萃分析，以检验相互作用是否主要是非附加性的（协同或拮抗），以及影响净反应的因素。将个体反应分为（拮抗/附加/协同），并根据微塑料暴露的分类变量（环境相关性、相互作用的胁迫因素、微塑料形态和测量的反应类别）以及暴露的鱼类（生活阶段、生态和家族），确定 838 个反应（36 项研究）的净反应是否符合附加模型。大多数反应被归类为拮抗（48%）和附加（34%），协同效应最少（17%）。对于所有相互作用的胁迫水平、鱼类家族和微塑料形态，净反应都符合附加模型。相比之下，对于生化反应、胚胎生活阶段、具有环境相关性的微塑料暴露和具有底栖-上层生态的鱼类，存在净拮抗作用，而对于具有底栖生态的鱼类，则存在协同作用。虽然仍存在大量知识空白，并进行了讨论，但迄今为止的数据表明，淡水鱼类对微塑料-胁迫的反应很少是协同的，因此，解决任何一种或两种胁迫因素都可能产生积极的管理和生物学结果。
