School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, Northern Ireland, UK; Queen's Marine Laboratory, Queen's University Belfast, 12-13 The Strand, Portaferry, BT22 1PF, Northern Ireland, UK.
School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, Northern Ireland, UK; Queen's Marine Laboratory, Queen's University Belfast, 12-13 The Strand, Portaferry, BT22 1PF, Northern Ireland, UK; Institute for Global Food Security, Queen's University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, Northern Ireland, UK.
Sci Total Environ. 2023 Jul 20;883:163582. doi: 10.1016/j.scitotenv.2023.163582. Epub 2023 Apr 20.
Microplastics are a ubiquitous and persistent form of pollution globally, with impacts cascading from the cellular to ecosystem level. However, there is a paucity in understanding interactions between microplastic pollution with other environmental stressors, and how these could affect ecological functions and services. Freshwater ecosystems are subject to microplastic input from anthropogenic activities (eg. wastewater), but are also simultaneously exposed to many other stressors, particularly reduced dissolved oxygen availability associated with climatic warming and pollutants, as well as biological invasions. Here, we employ the comparative functional response method (CFR; quantifying and comparing organism resource use as a function of resource density) to investigate the relative impact of different microplastic concentrations and oxygen regimes on predatory trophic interactions of a native and an invasive alien gammarid (Gammarus duebeni and Gammarus pulex). No significant effect on trophic interaction strengths was found from very high concentrations of microplastics (200 mp/L and 200,000 mp/L) or low oxygen (40 %) stressors on either species. Additionally, both gammarid species exhibited significant Type II functional responses, with attack rates and handling times not significantly affected by microplastics, oxygen or gammarid invasion status. Thus, both species showed resistance to the simultaneous effects of microplastics and deoxygenation in terms of feeding behaviour. Based on these findings, we suggest that the trophic function, in terms of predation rate, of Gammarus spp. may be sustained under acute bouts of microplastic pollution even in poorly‑oxygenated waters. This is the first study to investigate microplastic and deoxygenation interactions and to find no evidence for an interaction on a key invertebrate ecosystem service. We argue that our CFR methods can help understand and predict the future ecological ramifications of microplastics and other stressors across taxa and habitats.
微塑料是一种普遍存在且持久的全球性污染物，其影响从细胞水平到生态系统水平逐级传递。然而，人们对微塑料污染与其他环境胁迫因素之间的相互作用以及这些因素如何影响生态功能和服务知之甚少。淡水生态系统受到人为活动（如废水）产生的微塑料输入的影响，但同时也受到许多其他胁迫因素的影响，特别是与气候变暖、污染物以及生物入侵有关的溶解氧减少。在这里，我们采用比较功能反应方法（CFR；量化和比较生物对资源密度的利用功能）来研究不同微塑料浓度和氧气条件对原生和入侵外来端足类（鳚属和沼泽钩端螺旋体）捕食性营养相互作用的相对影响。在非常高的微塑料浓度（200mp/L 和 200,000mp/L）或低氧（40%）胁迫下，微塑料或低氧胁迫对这两个物种的营养相互作用强度都没有显著影响。此外，两种端足类都表现出显著的 II 型功能反应，攻击率和处理时间不受微塑料、氧气或端足类入侵状态的显著影响。因此，两种端足类在摄食行为方面都表现出对微塑料和缺氧同时作用的抵抗力。基于这些发现，我们认为，即使在贫氧水中，鳚属捕食率等捕食功能在短期内受微塑料污染的影响可能仍能维持。这是第一项研究微塑料和缺氧相互作用的研究，没有发现关键无脊椎动物生态系统服务受到相互作用的证据。我们认为，我们的 CFR 方法可以帮助理解和预测微塑料和其他胁迫因素在跨分类群和栖息地的未来生态后果。
