Coral Reefs Also Under Threat From Air Pollution
April 8, 2013

Atmospheric Aerosols Can Harm Coral Reef Growth Rates

redOrbit Staff & Wire Reports - Your Universe Online

Fine particles in the air resulting from burning coal or volcanic eruptions can negatively affect coral growth, a team of climate scientists and coral ecologists from the UK, Australia and Panama has discovered.

The study, which appears in this week´s edition of the journal Nature Geoscience, found that coral reefs respond to changes in the concentration of atmospheric pollution. Those particulates can shade the corals from sunlight and cause the water surrounding them to cool, thus leading to reduced growth rates, the researchers said.

“Coral reefs are the most diverse of all ocean ecosystems with up to 25% of ocean species depending on them for food and shelter,” lead author Lester Kwiatkowski, a PhD student from the University of Exeter, said in a statement. “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.”

“Particulate pollution or 'aerosols' reflect incoming sunlight and make clouds brighter,” added Dr. Paul Halloran, an ocean biogeochemistry expert at the Met Office Hadley Centre. “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.”

Kwiatkowski, Halloran and colleagues studied records obtained from within the coral skeletons, as well as ship-based observations, climate model simulations and statistical modeling in their research.

They found that coral growth rates in the Caribbean were affected by volcanic particle emissions in the early 1900s and human-caused aerosol emissions later on in the 20th century. The researchers hope that their efforts will help experts better understand how industrial and agricultural sources of aerosols can impact coral growth.

“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 industrialization and decarbonization,” said University of Queensland professor Peter Mumby.