David Wachenfeld, chief scientist at the Great Barrier Reef Marine Park Authority, the government agency that supervises the coral expanse off northeast Australia, said that ocean temperatures in the next month would be vital to how the reef recovers from heat-inducing bleaching.
“The forecasts… indicate that we can expect ongoing levels of thermal stress for at least the next two weeks and maybe three or four weeks,” Mr. Wachenfeld said in an update on the reef’s health that’s being released every week. “So this still is a critical time for the reef, and it is the weather conditions over the next two to four weeks that will determine the final outcome.”
Ocean temperatures over most of the reef were 0.5 to 1.5 degrees Celsius higher than the March average level. In places of the marine park in the south, which evaded the devastating effects of prior bleaching, ocean temperatures were two to three degrees Celsius above the average limit. The authorities have received 250 reports of observances of bleached coral because of the leveled ocean temperatures during an incredibly hot February.
The 345,400-square kilometer network listed in World Heritage has been damaged by four coral bleaching events since 1998. The most harmful were the most recent, in consecutive summers: 2016 and 2017.
Corals’ Condition Worsened
Experts fear that the most recent death rate could equal those devastating events.
“At the moment, it’s definitely the most extensive bleaching event we’ve ever had,” U.S. National Oceanic and Atmospheric Administration Coral Reef Watch scientist William Skirving said. “It’s certainly an end-to-end bleaching event with severe bits at each end, and it’s not looking good for the southern end, but it really depends on the weather in the next two weeks.”
Ove Hoegh-Guldberg, an expert from the Australian Research Council Center for Excellence in Coral Reef Studies, stated that the amount of recovering corals and the number of dying corals would not be known for a few weeks.
“I’m very worried about the situation given how warm the temperatures are on the Great Barrier Reef and what the projections are,” Mr. Hoegh-Guldberg said. “If it cools down a bit, they’ll recover or, if not, we may head off into something not too different from 2016 and 2017. We’re right at the fork in the road.”
Last year, the Great Barrier Reef Marine Park Authority reduced its prospect for the corals’ state from ‘poor’ to ‘very poor’ because of the warming oceans.