Late last year, researchers at Duke University’s Nicholas School of the Environment released a worrying study, suggesting that corals actually find plastic particles tasty. Their experiments showed that corals ingest microplastics, and may actually prefer the taste of certain chemicals over algae. Parley caught up with PhD student Austin Allen, one of the study’s co-authors, to find out more about this ongoing research.
What makes corals so vital and important for the oceans?
Coral reefs are under siege from a variety of threats, and this is important because they play many roles in the ocean. Many corals are foundational species that provide habitat for many types of animals. Coral reefs serve as nurseries for economically important fisheries, sequester carbon, and mitigate the impact of storms on coastal communities, amongst other functions. Additionally, their high biodiversity contributes to ecosystem resilience.
Can you briefly summarise your initial findings about the interactions between coral and plastic?
Our findings show that corals will ingest many types of plastics, and they are not able to expel all of the plastic they ingest. Additionally, they seem to prefer plastic over some types of particles. Corals feed in different ways. Some corals get the majority of their energy from symbiotic, photosynthesizing algae they maintain inside themselves, while others partly or exclusively rely on capturing plankton or absorbing dissolved chemicals. Our study was in a laboratory setting to simplify the questions we were asking, future studies will need to quantify the concentration of plastics found in corals in the wild. Future studies will also need to determine whether ingesting plastic could be reducing corals' ability to feed or whether toxic compounds could be leaching from the plastic and concentrating in the corals.
Between bleaching, habitat loss and now microplastics, corals are increasingly under threat. How serious is the plastic aspect – do we know yet?
Coral reefs face many threats – but we don't yet know the extent or impacts of plastic ingestion. What we do know is that climate change, overfishing, habitat destruction, and eutrophication (reduced oxygen) are having severe impacts. It's not all bleak though, and you can help. Besides reducing your carbon footprint, you can choose sustainable seafood (use the Seafood Watch App) and use reef-safe sunscreen (without oxybenzone). The EPA website has other ideas too. Recent research shows that reducing pollution, overfishing, and other local threats can provide corals the much-needed time to adapt to warming and acidifying oceans, as well as give us time to reduce carbon emissions.