CAREER: Temperature and microplastic effects on coral physiology and reproduction

This project involves research on the biological impacts of climate change and plastic pollution in one of the most diverse and productive ecosystems on Earth. At present, limited information exists on the abundance and distribution of microplastics (plastic particles < 5 mm) in tropical systems. This research examines microplastics abundance and chemical identity in Hawaiian coral reefs using samples from water, sediments, and coral tissue.

Multiple stressor experiments are providing key insights on the reproduction and the long-term effects of microplastics in corals with a compromised health state (bleached). The experiments address controversial findings in this emerging field such as how corals are more affected by plasticizers and what microplastic types are “tastier.” Understanding if and what type of microplastics can interfere with biological processes in corals helps to elucidate the extent to which microplastics cause metabolic disorders and influence the survival and recruitment of future generations.

When used in the context of global change, these data are critical for predicting the potential impact of these combined stressors on future corals and coral reefs. This project creates and an integrated program that promotes citizen science, middle-school student engagement and ocean literacy and research for schoolteachers from Hawaiian immersion schools.

The foundational insights gained through the research objectives improve our capacity to predict the response of coral communities to thermal bleaching events and microplastic pollution and can be applied to conservation and management efforts.

Climate change and pollution are major drivers in the degradation of coral reef ecosystems worldwide. Around 8 million tons of plastic end up in the oceans every year and the majority of plastic items currently found in the ocean are microplastics. Recent evidence suggests that microplastic pollution can negatively affect corals.

However, little is known about the abundance, exposure and risk of microplastics in coral reefs or whether microplastics will increase the vulnerability of corals to climate change. The research objectives are to: (i) Assess if and how temperature and microplastics (plastic particles < 5 mm) affect coral gametogenesis, fecundity and physiological performance with both field and laboratory studies, (ii) Quantify if bleached corals are more likely to ingest microplastics due to heterotrophic plasticity, (iii) Examine the physiological effects of microplastics exposure in corals under thermal stress and during recovery after bleaching, and (iii) Understand the mechanisms by which microplastics exposure may impact spawning synchrony and gamete viability.

The proposed education program is integrated with the research program by (i) designing a citizen science project to quantify and collect plastic data in Hawaiian beaches, (ii) providing research opportunities to middle-school students from low-income schools to gain first-hand field and research experience and (iii) developing a workshop for Hawaiian teachers using the bilingual NSF-LTER children’s book as a research and educational platform.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.