A study by the University of Exeter has provided the first ever evidence that coral reefs can recover from climate change.
The researchers surveyed ten sites located within the Bahamas, both inside and out of marine sanctuaries. These reefs, which were studied over a two and half year period, had been severely damaged by bleaching and by hurricane Frances. Sadly, only 2-percent of the world’s coral reefs are located within marine reserves.
Sea surface temperature changes are the most common cause of coral bleaching. Ocean acidification–an ongoing decrease in the ocean’s pH level–further perpetuates the bleaching effects of thermal stress even more. It decreases the ability of coral to produce calcium carbonate (chalk), which is what they are made of.
By the end of the project, coral cover in those protected areas increased by an average of 19-percent. Unprotected areas showed no recovery at all.
Professor Peter Mumby of the University of Exeter said: “Coral reefs are the largest living structures on Earth and are home to the highest biodiversity on the planet. As a result of climate change, the environment that has enabled coral reefs to thrive for hundreds of thousands of years is changing too quickly for reefs to adapt.”
The researchers concluded that protected reefs–areas not damaged by human activity like dredging and fishing–improved due to the lack of fishing.
“In order to protect reefs in the long-term we need radical action to reduce CO2 emissions. However, our research shows that local action to reduce the effects of fishing can contribute meaningfully to the fate of reefs. The reserve allowed the number of parrotfishes to increase and because parrotfish eat seaweeds, the corals could grow freely without being swamped by weeds. As a result, reefs inside the park were showing recovery whereas those with more seaweed were not. This sort of evidence may help persuade governments to reduce the fishing of key herbivores like parrotfishes and help reefs cope with the inevitable threats posed by climate change,” added Mumby.