Bleached branching coral (foreground) and normal branching coral (background). Keppel Islands, Great Barrier Reef
The beautiful corals which color the world's reefs and act as rich habitats for all manner of ocean-going creatures may be in trouble. The culprit? Climate change leading to a phenomenon
called coral bleaching:
Ruben van Hooidonk from the NOAA Atlantic Oceanographic and Meteorological Laboratory, who is lead author of the report, said the projections they arrived at will aid resource managers in better understanding coral bleaching, in turn allowing them to better plan for its effects.
Some locations in the report were referred to as "relative refugia," meaning these spots have fewer instances of extreme events and lower rates in temperature spikes, giving them more time for adapting to the effects of climate change.
"Managers may decide to use this information to protect these locations as refuges or protected areas. Or they may take other actions to reduce stress caused by human activities," said Van Hooidonk.
Many species of shallow water corals harbor photosynthetic microbes belonging to the genus
Symbiodinium. These tiny creatures come in various subspecies and often give coral its distinctive color. But the delicate balance between coral and microbes is upset even by slight changes in water chemistry. Rapidly warming water causes acidification, which in turn can kill the embedded microbes or cause them to be expelled, leaving the coral an unhealthy white color. Unlike other effects of climate change, often measured in decades or centuries, bleaching can transpire rapidly, causing the entire reef to collapse and begin crumbling into dust within just a few years.