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, pollution from air particles resulting from burning coal or volcanic eruptions can shade corals from sunlight and cool the surrounding water resulting in reduced growth rates.

Corals have been responding to changes in the concentration of particulate pollution in the atmosphere,

Dr. Paul Halloran of the team explains: “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 authors used 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 localized sources of aerosols such as industry or farming. 

Source article can be found here.