Up to 80 per cent of inshore reefs in WA's Kimberley region have been severely affected by a recent mass coral bleaching event.
Sophie Moore, Australian Associated Press News.com.au 6 Nov 17;
Up to 80 per cent of coral reefs in parts of Western Australia's Kimberley region were severely affected by recent global bleaching, scientists say.
Inshore Kimberley reefs suffered bleaching for the first time in 2016, when the most severe mass event on record damaged between 57 to 80 per cent of coral.
Bleaching occurs when a spike in sea temperatures puts coral under stress, causing it to expel the tiny photosynthetic algae responsible for its brilliant colours and turning them bone white.
Stressed coral struggles for food and to fight disease but can recover if the temperature drops.
Researchers from the University of Western Australia analysed aerial and underwater surveys to monitor the health of coral reefs along the WA coastline, from the Kimberley to Bremer Bay.
They found despite Kimberley corals being tougher than most, they were not immune to the 2016 bleaching.
"This is the first documented regional-scale bleaching event in WA during an El Nino year and the first time we have been able to measure the percentage of impacted corals," lead researcher Verena Schoepf told AAP.
El Nino is the natural warming of the central Pacific that affects weather around the world, while La Nina is the name for when it cools.
"Coral reefs in WA are now at risk of bleaching during both El Nino and La Nina years as different reefs are affected depending on their geography," Dr Schoepf said.
Ningaloo Reef was severely affected from 2010 to 2011 but escaped unharmed in the 2016 event which hit the Kimberley.
Dr Schoepft said bleaching had rapidly increased in frequency since 1980, caused by a hike in atmospheric carbon dioxide.
"It is extremely important to monitor bleaching events to see how coral is affected and how long it takes to recover," she said.
Like a skeleton, coral reefs are vital for marine life, support fishing and tourism industries and also to provide protection for coastlines during storms and prevent coastal erosion.
"Biomedical compounds to treat diseases such as cancer have also been found in reefs," Dr Schoepf said.
"It's a pharmacy of the future."
