Air Pollution Stunts Coral Growth, Research Finds

A new study has found that Air pollution stunts coral growth, new research from the University of Exeter has found. The fine particulate matter that is released into the air as a result of fossil fuel burning, amongst other things, effectively “shades” the coral and subsequently cools the water that they reside in, both of which slow the growth rate.


For those that don’t know, corals are large colonies of very simple animals that cooperatively build and maintain their “skeletons”, which they live in. Most types of coral rely on symbiotic photosynthetic algae for their energy, though there are some types which get their energy in other ways. They live all throughout all of the world’s oceans but are centered around the tropics,

“Although coral reefs grow under the sea it seems that they have been responding to changes in the concentration of particulate pollution in the atmosphere, according to a paper published in the journal Nature Geoscience by a team of climate scientists and coral ecologists from the UK, Australia and Panama.”

Lead author Lester Kwiatkowski, a PhD student from Mathematics at the University of Exeter, stated: “Coral reefs are the most diverse of all ocean ecosystems with up to 25% of ocean species depending on them for food and shelter. They are believed to be vulnerable to climate change and ocean acidification, but ours is the first study to show a clear link between coral growth and the concentration of particulate pollution in the atmosphere.”

Dr Paul Halloran of the Met Office Hadley Centre explained: “Particulate pollution or ‘aerosols’ reflect incoming sunlight and make clouds brighter. This can reduce the light available for coral photosynthesis, as well as the temperature of surrounding waters. Together these factors are shown to slow down coral growth.”


The researchers relied upon “a combination of records retrieved from within the coral skeletons, observations from ships, climate model simulations and statistical modelling. Their analysis shows that coral growth rates in the Caribbean were affected by volcanic aerosol emissions in the early 20th century and by aerosol emissions caused by humans in the later 20th century.”

“The researchers hope that this work will lead to a better understanding of how coral growth may change in the future, taking into account not just future carbon dioxide levels, but also localised sources of aerosols such as industry or farming.”

Professor Peter Mumby of the University of Queensland put the study in the context of global environmental change: “Our study suggests that coral ecosystems are likely to be sensitive to not only the future global atmospheric carbon dioxide concentration but also the regional aerosol emissions associated with industrialisation and decarbonisation.”

Coral reefs have been taking a hit in recent years from a variety of different sources, though almost all human-caused. It is currently estimated that 10% of the world’s coral reefs are already dead. Some areas are worse off than others, the Caribbean coral reefs are already mostly dead. It’s been estimated that by the year 2030, over 50% of the world’s coral reefs may be dead.

Image Credit: Coral and Clown Fish and Coral and Sky via Shutterstock

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