Kewalo Marine Laboratory, University of Hawai'i at Mānoa, 41 Ahui Street, Honolulu, HI 96813, USA.
Black in Marine Science, 522 W Riverside Dr., Spokane, WA 99201, USA.
Integr Comp Biol. 2024 Oct 28;64(4):1131-1140. doi: 10.1093/icb/icae143.
Microplastic pollution is an emerging stressor of concern to coral reef ecosystems, which are already threatened by additional global and local level anthropogenic stressors. The effects of ingesting microplastics alone on corals have been well studied, but the effects of the chemical composition of these particles have been understudied. Many microplastic-associated chemicals are endocrine disrupters potentially posing a threat to organismal reproduction. Therefore, the goal of this study was to determine if differences exist between the effects of microplastics themselves and microplastic leachate on Montipora capitata fertilization due to changes in fatty acid quantity and composition. Assays were conducted two years in a row which exposed M. capitata gamete bundles to either one of four types of recently manufactured, virgin microspheres (nylon, polypropylene, high-density polyethylene, or low-density polyethylene) at three concentrations (50, 100, or 200 particles/L) or microplastic leachates, presumably including plastic additives from these microspheres. Gamete fertilization was not impacted by microplastic particles themselves, but some of the microplastic leachate treatments with the same polymer type significantly reduced fertilization rates for M. capitata. Additionally, a total of 17 fatty acids were seen in both years, but neither fatty acid quantity nor composition correlated with observed declines in fertilization. Instead, fertilization and fatty acid data independently varied by concentration and polymer type, likely due to the presence of different chemicals. This study is the first to directly test the toxicity of microplastic leachate to coral reproduction. These findings show that microplastic-associated chemicals are an important stressor affecting successful coral fertilization and fatty acid quantity and composition and provide evidence for the negative effects of microplastic leachate to coral reproduction. Thus, plastic additives could pose an additional threat to coral replenishment and persistence in coral reef ecosystems.
微塑料污染是珊瑚礁生态系统关注的一个新兴胁迫因素，这些生态系统已经受到额外的全球和地方人为胁迫因素的威胁。单独摄入微塑料对珊瑚的影响已经得到了充分的研究，但这些颗粒的化学成分的影响却研究不足。许多与微塑料相关的化学物质是内分泌干扰物，可能对生物繁殖构成威胁。因此，本研究的目的是确定微塑料本身和微塑料浸出物对 Montipora capitata 受精的影响是否因脂肪酸数量和组成的变化而存在差异。这项实验连续两年进行，将 M. capitata 配子束暴露于四种新制造的、原始微球（尼龙、聚丙烯、高密度聚乙烯或低密度聚乙烯）中的任何一种，浓度分别为 50、100 或 200 个/升，或微塑料浸出物中，这些微球可能含有塑料添加剂。微塑料颗粒本身并没有影响配子的受精，但某些相同聚合物类型的微塑料浸出物处理显著降低了 M. capitata 的受精率。此外，在这两年中都观察到了总共 17 种脂肪酸，但脂肪酸数量和组成都与观察到的受精率下降无关。相反，受精和脂肪酸数据独立于浓度和聚合物类型而变化，这可能是由于存在不同的化学物质。本研究首次直接测试了微塑料浸出物对珊瑚繁殖的毒性。这些发现表明，与微塑料相关的化学物质是影响珊瑚成功受精以及脂肪酸数量和组成的一个重要胁迫因素，并为微塑料浸出物对珊瑚繁殖的负面影响提供了证据。因此，塑料添加剂可能对珊瑚礁生态系统中珊瑚的补充和生存构成额外威胁。
