A new study by University of Miami researchers has revealed that ocean acidification might be dissolving the limestone that forms the foundation of coral reefs along the Florida Reef Tract. The results show that this process takes place during the fall and winter months and affects the upper Florida Keys the most.
Ocean acidification refers to the absorption of carbon dioxide (CO2) from the atmosphere. Current laboratory experiments suggest that the acidity of the ocean will not become extreme enough to start dissolving reefs until 2050 to 2060, although the new study suggest otherwise.
In the new study, researchers collected water samples along the 124-mile stretch of the Florida Reef Tract north of Biscayne National Park to the Looe Key National Marine Sanctuary over the course of two years.
The results revealed that reef dissolution is posing a problem to reefs in the upper Keys, and the loss of limestone is significant enough that it trumps the amount that the corals are able to produce each year. This means that the destruction of these reefs is underway, which will take its toll on commercially and recreationally important fish species.
The fall and winter are a particularly vulnerable time for reefs due to low light and temperature conditions, as well as the annual decomposition of seagrass. This creates a slowing of reef growth, and in combination with the acidification of the ocean due to increased atmospheric CO2 absorption, this growth slows even more and has damaging effects.
"We don't have as much time as we previously thought," said Chris Langdon, professor of marine biology and ecology at the University of Miami and senior author of the study. "The reefs are beginning to dissolve away. This is one more reason why we need to get serious about reducing carbon dioxide emission sooner rather than later."
Since the data for the current study stems from 2009 to 2010, the team suggests that another analysis should be conducted to determine how the reefs have progressed.
"The worst bleaching years on record in the Florida Keys were 2014-2015, so there's a chance the reefs could be worse now," Langdon said.
The findings were published in the May 2 issue of the journal Global Biogeochemical Cycles.
