16/07/2020 - Meeting with Dr Hennige Coral Reef Researcher
Dr Sebastian Hennige from the University of Edinburgh, is a coral reef researcher who looks at the impacts of environmental change and pollutants to marine ecosystems. He was a contributing author in the 2019 Intergovernmental Panel on Climate Change, the Special Report on the Ocean and Cryosphere in a Changing Climate and lead editor of a United Nations Convention on Biological Diversity report on the impacts of ocean acidification on marine biodiversity. We contacted Dr Hennige to learn more about what causes coral bleaching and how our project would help relieve the issue.
To begin our interview we simply asked what factors are contributing to coral bleaching and Dr Hennige explained that the main issue is the rising sea temperature. In Australia where mass bleaching is more regular it tends to occur in the warmer seas to the north. When asked how sunscreen contributes to this he said that if we continue to add additional stress to areas where corals live, the combined effect of warmer seas and toxic compounds will “tip the scale” resulting in the complete bleaching of the coral. Therefore, any attempts to minimise other stresses on the reef will prevent exacerbating the problem. This means that our project will not solve coral bleaching entirely but instead reduce the oxidative stress corals experience increasing the likelihood that corals will be able to withstand rising sea temperatures and continue to support the organisms that live there.
In continuation of this discussion we asked him if he felt total bioremediation of coral reefs was possible and he explained to us how plastic degradation can complicate this issue. As plastics are broken down it leads to the formation of “transitioning compounds” which bacteria can adhere to and this becomes ingested by marine life. This is a widespread, complicated and sensitive issue for bioremediation and therefore, this would be a future goal. In response to this we removed bioremediation from our project's goals and focused our aim on the immediate goal of supporting coral ecosystems. He continued saying he feels there is a market for reef-safe sunscreens but current manufacturing processes are expensive. He stressed that people want to help the environment but purchasing power is limited and this is a gap in the market in which our product would be attractive. This was referred to as “consumer greed” the desire to feel like consumers are helping to solve an issue without having to make a commitment. Reduced purchasing power due to expensive products is a recurring theme in our human practices.
We also discussed the various experimental procedures used by scientists to test if sunscreen compounds were contributing to coral bleaching. Dr Hennige informed us that the most commonly used procedures involved placing coral into plastic bags and adding high concentrations of various sunscreens. The researchers would then track the colour change in the coral from normal to white. He explained how this initial study led to the discovery that sunscreen was inducing the lytic cycle promoting viral growth around the coral, this stresses the coral causing it to expel its symbiont algae, this aligned with our literature research. We asked if this was the only impact sunscreen had and he revealed that another study found that sunscreen compounds could also change the lipid composition in cells which resulted in the expulsion of algae. Another issue is that nano-particles produce ions in the water which are toxic to corals. This demonstrated to us that sunscreen has much wider effects on coral than we initially thought and that nanoparticles are not the perfect solution to coral bleaching they are presented as being. When asked if Hipposudoric Acid was likely to cause stress on corals Dr Hennige said it was unlikely because it is already present in water and therefore, will have a reduced impact compared to a novel inorganic compound. However, he recommended performing dispersal experiments and replicating previous studies. He explained how juvenile corals are often more tolerant than adults and thus these experiments may in invalid if performed on young corals. Unfortunately due to restricted lab access it is not possible for us to perform these experiments but it is important we think about the potential impacts of Hipposudoric Acid on corals and attempt these experiments as soon as it is viable.
This interview with Dr Hennige inspired us and demonstrated how sunscreens can be dangerous for coral reefs beyond what we had discovered in the primary literature. This helped us to define our primary goal - producing a reef-safe alternative UV filter that will reduce the oxidative stress corals experience helping to minimise bleaching events.