Arizona civil engineer Mo Ehsani thinks he has the answer to the global coral bleaching
crisis — a pipe that delivers cool water to stressed corals.
Bleaching, a consequence of climate change, is destroying some of the world’s most stunning reefs. “Our reckless acts are killing these beautiful creatures that have lived for 20 million years,” said Ehsani, professor emeritus of civil engineering at the University of Arizona. “What kind of legacy are we leaving behind?”
Coral bleaching occurs when ocean water is too warm, and corals expel the colored algae living in their tissues, a process that turns the coral completely white. Corals can survive a bleaching event, but it puts them under greater stress, making them vulnerable to further damage and death. A healthy, resilient reef can resist a stressful event, like bleaching, or recover from it, but only if temperatures quickly return to normal.Ehsani’s proposal is simple, low cost and potentially sustainable. It would use energy generated by ocean waves to pump cool water to the heat-stressed corals through a durable, lightweight pipe he designed.
“There is an endless supply of cool water just a short distance away, at the bottom of the ocean,” he said. “The heating of the water comes from above — from the sun beating down on the ocean.” He explained that surface water heats up faster than the rest of the ocean.
The pipe is made of fiber-reinforced polymer, rather than concrete or steel like conventional pipes. This makes it easy to build, transport and install. “It’s almost like a hose,” Ehsani said. “It’s not subjected to any major loads or stresses. We can drop it right into the ocean, and it can handle the stresses.”
