Living in a High CO2 World: How Coral Dependent Communities will Fare

Underwater paradise, full of vibrant colors, filled with an abundance of different species.

Sounds perfect, right? The problem is, coral reefs are being damaged due to elevated sea surface temperatures and chemical changes known as ocean acidification. Of particular concern is the impact on coral systems, because of ocean acidification impacts on communities that depend on coral reef ecosystems for food or shoreline protection from erosion.

A recent study looked by Linwood Pendleton looked at human dependence on coral reef ecosystems in relation to two global stressors, elevated sea surface temperatures and ocean acidification. Pendleton is an environmental economist and the Director of Ocean and Coastal Policy at Duke’s Nicholas, North Carolina. The research conducted by Pendleton and his team focuses on both sea surface temperatures and ocean acidification as these stressors are “largely beyond the control of coastal communities and management bodies”.

In a recent paper, Pendleton and colleagues used an indicator approach identifying places where key environmental factors that are driven by high CO2 levels may put reef-dependent people most at risk. The researchers mapped indicators of biological and physical factors, as a way of integrating natural and social science, to identify early actions and opportunities to combat global environmental change, and reflect a geographical distribution of coral stress intensity.

Pendleton stated that “the ability of coral reef ecosystems to recover from damaging events is likely to be suppressed by the elevated sea surface temperature and ocean acidification expected to occur in a high-CO2 world”.

Increasing atmospheric CO2 levels leads to polar ice caps melting and increased death rates of coral ecosystems. Increased acidity makes it difficult for coral polyps to build exoskeletons, impeding growth and leaving them vulnerable to thermal stress and other threats.

Changing sea surface temperature and ocean acidification in the marine environment substantially reduces biodiversity and is attributed to the near extinction of the Beluga whale, Leatherback sea turtle, Antarctic blue whale and other marine animals.

As the water heats up, it expands, causing flooding of coastal habitats for humans as well as marine organisms and leads to shoreline erosion.

Fixing on biological, physical and social science factors help understand how “human dependence on coral ecosystems will be affected by globally-driven threats to corals expected in a high CO2 world.”

The research identified reef-dependent areas such as Western Mexico, Micronesia, Indonesia and parts of Australia as places most at risk of higher impacts. There is “less data for ocean acidification in reef-dependent areas” which suggests that further research should be done to help human communities better prepare for a high CO2 world. These areas that face future coral bleaching would benefit from globally and locally monitored data for reef health.

While this study strengthens our understanding of ocean acidification and elevated sea surface temperature, Pendleton recognizes that the ecological health of coral reefs depends on many other factors. We need to remember that threats to this valued resource come from overfishing, land-based runoff, agriculture and predatory outbreaks.

Pendleton suggests more and better social and economic science is needed to understand “how humans will respond to projected environmental changes in coral reef ecosystems.”

Original Paper:

Pendleton, L., Comte, A., Langdon, C., Ekstrom, J. A., Cooley, S. R., Suatoni, L., ... & Doherty, C. (2016). Coral Reefs and People in a High-CO2 World: Where Can Science Make a Difference to People?. PloS one, 11(11), e0164699.

By: Alice Walsh, University of Portsmouth, School of Biology (Institute of Marine Sciences)

ecoCURRENTS is a joint initiative between ECO magazine and select universities, which benefits science students by recruiting them to summarize the latest marine science research and providing them with a published byline. Beginning in December 2016, students from University of Portsmouth, School of Biological Sciences (Institute of Marine Science) contributed short articles to ECO editor Greg Leatherman. These are published online, with select articles also appearing in ECO’s print edition.

ECO expects to add more universities to this initiative during 2017. Interested administrators should contact Greg Leatherman at This email address is being protected from spambots. You need JavaScript enabled to view it..

Special thanks goes to Kira Coley, a lecturer in science communication at the University of Portsmouth, who played a major role in getting ecoCURRENTS underway.

ECO Magazine is a marine science publication committed to bringing scientists and professionals the latest ground-breaking research, industry news, and job opportunities from around the world.

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