WASHINGTON: For the first time ever, scientists have found corals that were thought to have been killed by heat stress have recovered, a glimmer of hope for the world’s climate change-threatened reefs, reports AFP.
The chance discovery, made by Diego K. Kersting from the Freie University of Berlin and the University of Barcelona during diving expeditions in the Spanish Mediterranean, was reported in the journal Science Advances on Wednesday. Kersting and co-author Cristina Linares have been carrying out long-termmonitoring of 243 colonies of the endangered reef-builder coral Cladocora caespitosa since 2002, allowing them to describe in previous papers recurring warming-related mass mortalities.
“At some point, we saw living polyps in these colonies, which we thought were completely dead,” Kersting told AFP, adding it was a “big surprise.”
Coral are made up of hundreds to thousands of tiny creatures called polyps that secrete a hard outer skeleton of calcium carbonate (limestone) and attach themselves to the ocean floor.
Heat waves kill these animals — by either essentially roasting them alive or causing them to eject the symbiotic algae that live within them and provide them nutrients, thus leading to coral bleaching.
A quarter of the coral cover of Spain’s Columbretes Islands was lost to a particularly extreme heat wave in 2003.