Interactive effects of microplastic pollution and heat stress on reef-building corals. (1st December 2021)

• Record Type: Journal Article
• Authors: Reichert, Jessica; Tirpitz, Vanessa; Anand, Rajshree; Bach, Katharina; Knopp, Jonas; Schubert, Patrick; Wilke, Thomas; Ziegler, Maren
• Is Part Of: Environmental pollution. Volume 290(2021)
• Publication Date: 2021-12-01
• Subjects: Microplastic -- Coral reef ecosystems -- Bleaching -- Heatwave -- Global change -- Aquarium experiment; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2021.118010
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Plastic pollution is an emerging stressor that increases pressure on ecosystems such as coral reefs that are already challenged by climate change. However, the effects of plastic pollution in combination with global warming are largely unknown. Thus, the goal of this study was to determine the cumulative effects of microplastic pollution with that of global warming on reef-building coral species and to compare the severity of both stressors. For this, we conducted a series of three controlled laboratory experiments and exposed a broad range of coral species ( Acropora muricata, Montipora digitata, Porites lutea, Pocillopora verrucosa, and Stylophora pistillata ) to microplastic particles in a range of concentrations (2.5–2500 particles L −1 ) and mixtures (from different industrial sectors) at ambient temperatures and in combination with heat stress. We show that microplastic can occasionally have both aggravating or mitigating effects on the corals' thermal tolerance. In comparison to heat stress, however, microplastic constitutes a minor stressor. While heat stress led to decreased photosynthetic efficiency of algal symbionts, and increased bleaching, tissue necrosis, and mortality, treatment with microplastic particles had only minor effects on the physiology and health of the tested coral species at ambient temperatures. These findings underline that while efforts to reduce plastic pollution should continue, they should not replace more urgent efforts to halt global warming, which are immediately needed to preserve remaining coral reef ecosystems. Graphical abstract: Image 1 Highlights: Microplastics had minor cumulative effects on reef-building corals under heat stress. The impact of microplastics was small when compared to that of heat stress. Different concentrations and mixtures of microplastics had little effect on corals. Microplastics altered bleaching response, decreased mortality and photosynthesis. The observed effects of microplastic were species-specific.