Study of coral reefs in Florida and Hawaii show accelerated erosion
After conducting a study of five coral reef tracts in Florida, Hawaii and the Caribbean, scientists have determined that coastal communities are under increasing threat from storms, waves and erosion, as a result of sea level rise.
Healthy Elkhorn coral near unpopulated Buck Island, US Virgin Islands.
At these sites–located in the Florida Keys the US Virgin Islands and Maui in Hawaii–the degradation of coral reefs has caused sea floor depths to increase. Over the past several decades, sand and other sea floor materials are also being eroded, and not by any small amount.
Overall, the sea level elevation decreased by 0.09 to 0.8 meters at all five sites. At the Maui site, sea floor losses amounted to 81 million cubic meters of sand, rock and other materials – that's 32,000 times the size of an Olympic swimming pool!
Due to the combined effects of rising seas (from climate change) and sea floor erosion, water depths have risen to levels that would normally not occur until around the year 2100.
The findings of the study, conducted by the US Geological Survey (USGS), were published in the recent issue of the Biosciences journal.
Lead author biogeochemist Kimberly Yates of the USGS' St. Petersburg Coastal and Marine Science Center said, “At current rates, by 2100 sea floor erosion could increase water depths by two to eight times more than what has been predicted from sea level rise alone.”
Although specific factors for the accelerated erosion in the five coral communities was not mentioned in the study, the authors listed factors responsible for declining coral reefs worldwide, such as natural processes, coastal development, overfishing, pollution, coral bleaching, disease and ocean acidification.
Despite the dismal tone of the findings, there was a glimmer of hope. “We saw lower rates of erosion – and even some localized increases in seafloor elevation – in areas that were protected, near refuges, or distant from human population centers,” said Yates.
Although these were not sufficient to offset the ecosystem-wide erosion at the five sites, it would appear that such protected marine areas were a possible solution to counter the degradation.
According to John Haines, Program Coordinator of the USGS Coastal and Marine Geology Program, “This study tells us that they [coral reefs] have a critical role in building and sustaining the physical structure of the coastal seafloor, which supports healthy ecosystems and protects coastal communities. These important ecosystem services may be lost by the end of this century, and nearby communities may need to find ways to compensate for these losses.”