This summer, it was all over the media. Driven by the climate crisis, the oceans have now also passed a critical point, the absorption of CO2 is making the oceans increasingly acidic. The shells of certain sea snails are already showing the first signs of damage. But also the skeleton structures of coral reefs are deteriorating in more acidic conditions. This is especially concerning given that corals are already suffering from marine heatwaves and pollution, which are leading to bleaching and finally to the death of entire reefs worldwide. But how exactly does ocean acidification affect reef structures?
Prof. Dr. Tali Mass, a marine biologist from the University of Haifa, Israel, is an expert on stony corals. Together with Prof. Dr. Paul Zaslansky, X-ray imaging expert from Charité Berlin, she investigated at BESSY II the skeleton formation in baby corals, raised under different pH conditions. Antonia Rötger spoke online with the two experts about the results of their recent study and the future of coral reefs.
What types of corals did you examine?
Tali Mass: These are coral larvae from colonies of the stony coral Stylophora pistillata from the Red Sea. We collected them ourselves during spawning nights in April 2020 at a depth of a few metres. They come from the reef next to the Interuniversity Institute of Marine Sciences in the Gulf of Eilat, Israel. We allowed these larvae to grow in our environment simulators aquaria system for several weeks and exposed them to different pH-conditions. Some tanks contained normal seawater, while others replicated conditions that simulated acidity predicted at the end of this century, assuming no climate protection measures are taken worldwide. This scenario, known as RCP8.5, is associated with significant acidification and global temperature increase of four degrees or more, expected to cause major global disruption. In this context, corals are giving us a window into a potential, bleak future.
Read more on the HZB website
Image: Stony corals in the Red Sea are rich ecosystems, hosting various fish and other marine organisms. The reef is formed by countless coral animals (polyps). The corals live symbiotically with certain algae, which give them their vibrant colour
Credit: © Tali Mass