Global Patterns and Variability in Coral Responses to Plastic Pollution

Plastic pollution has emerged as a pervasive threat to corals, yet its ecological impacts remain poorly synthesized across spatial and experimental contexts. Here, we present a systematic review and meta-analysis of coral responses to plastic pollution, synthesizing peer-reviewed studies published between 2011 and early 2025. Literature searches of Web of Science, Scopus, and Google Scholar identified 243 screened publications, of which 103 met strict inclusion criteria, including 38 field-based surveys and 65 laboratory exposure studies. A subset of 23 studies contributed to the meta-analysis. Plastic debris was widely detected in corals, but reported biological responses varied among studies. Meta-analytic effect sizes were highly heterogeneous (I² > 99%), reflecting the influence of factors such as temperature stress, pathogen exposure, nutrient enrichment, and the diversity of experimental designs across studies. Moderator analyses indicated that polymer type significantly influenced coral responses in laboratory studies, while exposure duration had no effect. In field studies, geographic region was a major source of variability, likely linked to differences in local pollution pressures and reef conditions. Across study types, tissue damage was the most frequently reported impact, and plastic exposure was often associated with increased disease susceptibility. These findings expose critical gaps in methodological consistency and underscore the need for standardized, ecologically relevant approaches to studying plastic-coral interactions. Addressing plastic pollution impacts on coral reefs will require not only improved waste management but also coordinated research frameworks that capture the complex, context-dependent nature of coral responses across global reef environments.