The Great Barrier Reef, one of the world’s most valuable habitats, lost half of its coral populations in the past quarter century. A decline announced by researchers in Australia would continue unless drastic measures were taken to mitigate the effects of climate change.
The researchers examined coral colonies along the reef between 1995 and 2017 and found that almost every species of coral had declined.
The colony sizes were smaller; There were fewer “big mommies” or older big corals producing baby corals. and there were fewer of those babies that are vital to the reef’s future breeding ability.
“Our results show that the Great Barrier Reef’s ability to recover – its resilience – is compromised compared to the past with fewer babies and fewer large adult breeders,” said Dr. Andy Dietzel, the study’s lead author. said in a statement.
The study was published on Wednesday in the journal Proceedings of the Royal Society.
Dr. Dietzel and other researchers at the ARC Center of Excellence for Coral Reef Studies in Queensland, Australia measured changes in colony size to understand coral breeding ability.
bleaching – A process by which corals expel algae and turn white as water temperatures rise – contributed to this steep losses of coral colonies in the northern and central Great Barrier Reef in 2016 and 2017. The southern part of the reef was also exposed to record temperatures in early 2020, according to researchers, who cited climate change as a major driver of reef disruption.
“There’s no time to waste,” the researchers said in their statement. “We have to cut greenhouse gas emissions as quickly as possible.”
“We used to think that the Great Barrier Reef was protected by its sheer size – but our results show that even the largest and relatively well-protected reef system in the world is increasingly compromised and in decline,” one of the researchers, Terence Hughes, told a statement.
The decline in “branched and tabular corals”, which are critical habitats for fish, is particularly pronounced, according to the researchers.
“These were hardest hit by record temperatures that led to mass bleaching in 2016 and 2017,” said Professor Hughes.
“The changes to the reef are shocking,” he said added on twitter.
He lamented what he saw as a lack of attention on the study of heads of government in Australia, the world’s largest coal exporter. The government has resisted calls for a reduction in CO2 emissions Even if heat waves, drought and fires continue to reveal the country’s vulnerability to climate change.
Home to a wide variety of marine life, the Great Barrier Reef has between 300 and 400 species of coral and stretches for thousands of kilometers along the Australian coast.
“You can literally see it from space,” said Deron Burkepile, Professor in the Department of Ecology, Evolution, and Marine Biology at the University of California at Santa Barbara.
Coral reefs around the world are responsible for billions of dollars in tourism and provide habitats for fish that feed nearly a billion people on the planet, he said.
The Australian researchers’ findings are significant as they focused on the reef’s breeding capacity and its ability to recover from devastating bleaching events caused by man-made climate change.
“The situation is dire,” said Professor Burkepile.
But people shouldn’t feel hopeless about the future of coral reefs, he said, even as they wait for world leaders to take more aggressive steps to curb the effects of climate change.
At the local level, for example, nitrogen pollution – which exacerbates bleaching – can be controlled by reducing the runoff of fertilizers and wastewater. according to a study that Professor Burkepile did with other researchers at his university.
“The other thing we need to take away is that coral reefs are amazingly resilient,” he said. “If we don’t damage them all the time, they will recover.”
Kitty Bennett contributed to the research.