The FINANCIAL — Australia’s Great Barrier Reef is showing signs of heat stress in several coral regions, increasing the chances of another major bleaching event. The iconic reef, which runs 2,300 kilometres down Australia’s north eastern coast has only just begun to recover after being heavily hit by two consecutive years of coral bleaching in 2016 and 2017 — both of which were among the warmest years on record. Coral reefs around the globe face uncertain futures as ocean temperatures continue to climb.
The Great Barrier Reef could be about to experience its most widespread outbreak of mass coral bleaching ever seen, according to an analysis from the US government’s National Oceanic and Atmospheric Administration. Pockets of bleaching are being seen in areas including Lizard Island, north of Cooktown, and more than 1,100 kilometres south-east at Heron Island, off Gladstone. Corals bleach if they sit in unusually warm waters for long periods. The algae that provides food and the coral’s colour separate from the animal, leaving behind a visible white skeleton. Severe bleaching can kill some corals, and weaken others. Extreme heat can also kill corals almost immediately, The Guardian reported.
Unfortunately, coral reef ecosystems are severely threatened. Some threats are natural, such as diseases, predators, and storms. Other threats are caused by people, including pollution, sedimentation, unsustainable fishing practices, and climate change, which is raising ocean temperatures and causing ocean acidification. Many of these threats can stress corals, leading to coral bleaching and possible death, while others cause physical damage to these delicate ecosystems. Corals are able to recover from bleaching events if conditions improve before they die, though it can take many years for the ecosystems to fully heal. Scientists are also testing new ways to help coral reef ecosystems, such as growing coral in a nursery and then transplanting it to damaged areas, National Oceanic and Atmospheric Administration stated.
Coral reefs protect coastlines from storms and erosion, provide jobs for local communities, and offer opportunities for recreation. They also are a source of food and new medicines. Over half a billion people depend on reefs for food, income, and protection. Fishing, diving, and snorkeling on and near reefs add hundreds of millions of dollars to local businesses. The net economic value of the world’s coral reefs is estimated to be nearly tens of billions of U.S. dollars per year. These ecosystems are culturally important to indigenous people around the world, according to National Oceanic and Atmospheric Administration.
About 70-90% of all existing coral reefs are expected to disappear in the next 20 years due to warming oceans, acidic water and pollution, said scientists from the University of Hawaii Manoa, who presented their findings Monday at an ocean sciences conference, CNN reported.
Rising sea surface temperatures and acidic waters could eliminate nearly all existing coral reef habitats by 2100, suggesting restoration projects in these areas will likely meet serious challenges, according to new research presented at the Ocean Sciences Meeting 2020.
In August, the government agency that manages Australia’s Great Barrier Reef downgraded its outlook for the corals’ condition from “poor” to “very poor” due to warming oceans. Florida scientists have enacted a 10-year, $100 million program in an effort to stop coral reef deaths in the Florida Keys, New York post reported.
“Trying to clean up the beaches is great and trying to combat pollution is fantastic. We need to continue those efforts,” Setter said. “But at the end of the day, fighting climate change is really what we need to be advocating for in order to protect corals and avoid compounded stressors,” said University of Hawaii Manoa biogeographer Renee Setter.