Poster Preview
•Previous research in our laboratory has demonstrated that the presence of polyvinyl chloride (PVC) microplastic fragments inhibits bleaching recovery in sea anemones (a coral model)1 •To examine the chemical effects of microplastic pollution on coral symbionts in isolation, cultures of the zooxanthella Breviolum minutum were treated with three different concentrations of dimethyl phthalate (DMP), plus a no-exposure control2 •While analyses are ongoing, our hypothesis that if as DMP concentration increases, photochemical efficiency decreases, this would indicate that DMP chemically inhibits zooxanthellae photosynthesis •If DMP does not inhibit zooxanthellae photosynthesis, decreased photosynthetic efficiency of the holobiont is due negative interactions with host organism biology
College
College of Arts & Sciences
Mentor Information
John Parkinson
Description
Coral bleaching is the process by which corals lose their symbiotic microalgae in response to stressful conditions. These photosymbionts, known as zooxanthellae, give corals their color and sustain host growth through mutualistic nutritional exchange. Bleaching events are becoming more common and severe, driving research into coral conservation and the resilience of each partner in the symbiosis. Yet it is unknown how certain pollutants, such as microplastics, may affect bleaching outcomes. Previous research in our laboratory has demonstrated that the presence of polyvinyl chloride (PVC) microplastics inhibits bleaching recovery in sea anemones (a coral model), but it remains unclear whether the effect was chemical or strictly physical. To examine the chemical effects of microplastic pollution on coral symbionts in isolation, cultures of the zooxanthella Breviolum minutum, a symbiont of Atlantic sea anemones and corals, were treated with three different concentrations of dimethyl phthalate (DMP), a common plasticizer in PVC, plus a no-exposure control (n = 3 replicates per treatment). Algal photochemical efficiency (Fv/Fm) was monitored using a JUNIOR PAM fluorometer before DMP exposure (day 0) and every other day after exposure up to the end of the experiment (10 days total). Analyses are ongoing, but we predict that significant decreases in Fv/Fm, proportional to the dosage of DMP, would indicate that DMP chemically inhibits zooxanthellae photosynthesis, which may reduce B. minutum’s ability to be incorporated as a symbiont by bleached hosts. This information can be used to further explore the nature of the effects microplastic pollution `has on coral bleaching.
Chemical Effects of Microplastics on Photochemistry in a Coral-Associated Zooxanthella
Coral bleaching is the process by which corals lose their symbiotic microalgae in response to stressful conditions. These photosymbionts, known as zooxanthellae, give corals their color and sustain host growth through mutualistic nutritional exchange. Bleaching events are becoming more common and severe, driving research into coral conservation and the resilience of each partner in the symbiosis. Yet it is unknown how certain pollutants, such as microplastics, may affect bleaching outcomes. Previous research in our laboratory has demonstrated that the presence of polyvinyl chloride (PVC) microplastics inhibits bleaching recovery in sea anemones (a coral model), but it remains unclear whether the effect was chemical or strictly physical. To examine the chemical effects of microplastic pollution on coral symbionts in isolation, cultures of the zooxanthella Breviolum minutum, a symbiont of Atlantic sea anemones and corals, were treated with three different concentrations of dimethyl phthalate (DMP), a common plasticizer in PVC, plus a no-exposure control (n = 3 replicates per treatment). Algal photochemical efficiency (Fv/Fm) was monitored using a JUNIOR PAM fluorometer before DMP exposure (day 0) and every other day after exposure up to the end of the experiment (10 days total). Analyses are ongoing, but we predict that significant decreases in Fv/Fm, proportional to the dosage of DMP, would indicate that DMP chemically inhibits zooxanthellae photosynthesis, which may reduce B. minutum’s ability to be incorporated as a symbiont by bleached hosts. This information can be used to further explore the nature of the effects microplastic pollution `has on coral bleaching.
