Are Coral Reefs Reacting to Climate Change?

The Marine Climate Change Unit aims to understand how coral reef fish adapt to environmental changes such as climate change, heatwaves, overfishing and urbanization. Earth’s oceans are warming and acidifying due to increasing anthropogenic CO2 production, and extreme events such as marine heatwaves are increasing in frequency, duration and magnitude. Coral reef fish are especially vulnerable to spikes in temperature because they are already living close to their thermal limits. Determining which species can adapt to rapid environmental change, and how they will do so, is critical for predicting the ecological effects of climate change and their impact on the world economy.

In the laboratory, the researchers investigate how short-term changes, as well as heritable changes in gene expression in multiple fish species are affected by increases in sea level temperature and acidity. They study animals that are descended from wild breeding pairs and have been reared in OIST’s aquariums over several generations. Using a unique device called the Heatwaves Simulator aquarium system based at OIST’s Marine Science Station, they expose fish to specific conditions, including the temperature and acidity level predicted to occur in seawater by the end of the century. They combine these manipulations with a range of advanced genomic technologies to identify the cellular mechanisms that allow coral reef fish communities in Okinawa, and around the world, to acclimate and adapt to changing conditions.

The researchers also investigate how different fish populations adapt to changes in their natural ecosystems. Recently, they gained access to several global locations at which natural volcanic CO2 seeps located in coral reefs bubble out to act as analogues of climate change. These sites include Iwotorishima and Shikine Islands in Japan, Milne Bay in Papua New Guinea, Bouraké Bay in New Caledonia, and White Island in New Zealand. There, CO2 dissolves into the seawater surrounding the reef, creating a natural laboratory for studying the effects of projected future ocean acidification on tropical fish communities.

Project Collaborators

• Professor Philip Munday, ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Australia
• Professor Celia Schunter, The University of Hong Kong & Swire Institute of Marine Science, Hong Kong, SAR
• Professor Martin Grossel, RSMAS, University of Miami, Florida, USA

Project Publications

• Veilleux H. et. al., Mechanisms of transgenerational acclimation to a warming ocean. 2015, Nature Climate Change.
• Ryu T. et al. The epigenetic landscape of transgenerational acclimation to ocean warming. 2018, Nature Climate Change.
• Schunter S. et. al., Molecular signatures of transgenerational brain response to ocean acidification in a reef fish. 2016, Nature Climate Change.
• Schunter S. et. al., An interplay between plasticity, epigenetics, and parental phenotype determines impacts of ocean acidification on a reef fish. 2017, Nature Ecology and Evolution.
• Species-specific molecular responses of wild coral reef fishes during a marine heatwave. Moisés A Bernal, Celia Schunter, Robert Lehmann, Damien J Lightfoot, Bridie JM Allan,
• Heather D Veilleux, Jodie L Rummer, Philip L Munday and Timothy Ravasi. Science Advances 6 (12), eaay3423, March 1, 2020. doi.org/10.1126/sciadv.aay3423.