Scientists have been keeping a close eye on Australia's Great Barrier Reef lately due to the lower water temperatures that cause coral bleaching, which is the process whereby the corals expel their algae and turn white. Now, a new study reveals a new danger that could threaten the life of the world's largest coral reef system: coal shipping.
The data reveals that coal dust in seawater can kill corals and stunt the growth rate of seagrasses and fish, leading experts to suggest that a major shipping disaster could significantly harm the Great Barrier Reef.
"Corals exposed to the highest concentrations of coal dust died within two weeks," said Kathryn Berry of James Cook University and first author of the study. "Corals exposed to lower concentrations of coal lasted longer, but most of them also died after four weeks of exposure. While some fish and seagrass died from coal dust exposure, it mostly stunted their growth by half compared to clean water."
In controlled experiments within the National Sea Simulator at the Australian Institute of Marine Science, the team examined the responses of marine species over time as they were exposed to fine coal particles. Coal dust commonly enters the marine environment at loading and storage facilities where it is then transported into the sea during transport as well as through shipping disasters.
One recent shipping disaster took place in 2013 when the MV Smart broke apart in South Africa while carrying more than 140,000 tons of coal. In addition, the Shen Neg 1 ran aground on the Great Barrier Reef back in 2010, with 60,000 tons of coal remaining on board after the accident.
"Risks to the Great Barrier Reef posed by large coal spills depend on the probability of an accident and the potential impacts to marine life," said Andrew Negri of the Australian Institute of Marine Science and co-author of the study. "While the likelihood of a major spill on a coral reef or seagrass meadow is low, we are now beginning to understand the likely consequences."
The team hopes that the results will help managers of coal shipping activities better understand the dangers and consequences of mismanagement.
"This research will allow decision makers to understand the risks to marine life to identify the species that are most vulnerable," said Mia Hoogenboom of James Cook University and co-author of the study.
The findings were published in the May 13 issue of Scientific Reports.
