To some, coral reefs are just the whimsical undersea environments that are fun to admire and that house some of the world’s most interesting creatures.
But many people’s knowledge about coral reefs and climate change stops at coral bleaching — the phenomenon where corals turn white and die in reaction to extreme temperatures. While this is a pivotal part of reef research, it is by no means the only problem that has arisen from the changing climate, said John Rippe, a graduate student and doctoral candidate for marine sciences in UNC's College of Arts and Sciences.
In studying coral density and growth rates in the reef system of the Florida Keys, researchers from the UNC Department of Marine Sciences have found another underlying issue with dangerous implications for marine life. By studying CT scans of drilled cores from two different species of reef-building corals across the reef tract, the researchers found some unexpected results.
“In a lot of areas — for example, in the Belize region — we see declining growth rates,” said Rippe, who led the study. “In this study, we saw that both extension and calcification have been pretty stable, which is not what we expected. But we found that the density of the coral skeletons is actually declining.”
In the Belize Mesoamerican Barrier Reef System, the rates of extension, or the growth of coral reefs upwards, are declining. However, the corals of the Florida Keys are experiencing declining skeletal density instead of changing growth rates.