‘Cooked’: Study finds Great Barrier Reef transformed by mass bleaching

‘Cooked’: Study finds Great Barrier Reef transformed by mass bleaching

SOURCE: The Sydney Morning Herald DATE: April 18, 2018 SNIP: Corals in the Great Barrier Reef have a lower tolerance to heat stress than expected, contributing to a permanent transformation of the mix of species in some of most pristine regions, a team of international researchers has found. The scientists examined the impact of the 2016 marine heatwave that alone caused the death of about one-third of the Great Barrier Reef corals, mostly centered on the northern third section. They studied how much abnormal heat triggers bleaching, the additional heat that killed the corals, and the accumulation needed to cause “an ecological collapse in the transformation of species”, said Terry Hughes, Director of the ARC Centre of Excellence for Coral Reef Studies at James Cook University, and the lead of author of the paper published Thursday in Nature. The thresholds “are lower than we thought they would be“, Professor Hughes told Fairfax Media. Just as coral species responded differently to the heat stress, so too have fish species that depend on them. Butterfly fish, for instance, feed on only a couple of coral species. “If their diet disappears, so do they,” Professor Hughes...
Heartbroken scientists lament the likely loss of ‘most of the world’s coral reefs’

Heartbroken scientists lament the likely loss of ‘most of the world’s coral reefs’

SOURCE: Grist DATE: January 5, 2018 SNIP: For decades, marine scientists have been warning of the demise of coral reefs in a warming world. But now, those warning calls have reached a full-scale alarm, leaving researchers at a loss for exactly how best to save the reefs. A study published Thursday in Science by some of the world’s top coral experts amounts to a last rites for the ecosystems often referred to as “the tropical rainforests of the sea.” Scientists surveyed 100 reefs around the world and found that extreme bleaching events that once occurred every 25 or 30 years now happen about every five or six years. “These impacts are stacking up at a pace and at a severity that I never had anticipated, even as an expert,” says Kim Cobb, a climate scientist and coral researcher at the Georgia Institute of Technology. “It’s really the rapidity of it that is so sobering and shocking — and for me personally, life-altering.” “Before the 1980s, mass bleaching of corals was unheard of,” Terry Hughes, a coral scientist at Australia’s James Cook University and lead author of the new study, said in a statement. The new study finds that 94 percent of surveyed coral reefs have experienced a severe bleaching event since the 1980s. Only six sites surveyed were unaffected. They are scattered around the world, meaning no ocean basin on Earth has been entirely spared. “It is clear already that we’re going to lose most of the world’s coral reefs,” says study coauthor Mark Eakin, coordinator of the National Oceanic and Atmospheric Administration’s Coral Reef Watch program. He adds...
Coral Bleaching Has Ravaged Half of Hawaii’s Reefs

Coral Bleaching Has Ravaged Half of Hawaii’s Reefs

SOURCE: Earther DATE: November 8, 2017 SNIP: Last week, scientists reported that half of Hawaii’s coral reefs suffered serious bleaching in 2014 and 2015 as part of an ongoing, three-year global bleaching event that researchers are still trying to get a handle on. Hawaii is home to some of the most spectacular reefs in the U.S., which bring in around $800 million a year in revenue. Around 56 percent of the Big Island’s corals bleached, along with 44 percent on West Maui and 32 percent of the reefs around Oahu according to an Associated Press report. “In the 2030s, 30 to 50 percent of the years will have major bleaching events in Hawaii,” Kuulei Rogers, a scientist at the Hawaii Institute of Marine Biology, told the...
Climate Change Has ‘Permanently’ Changed the Great Barrier Reef

Climate Change Has ‘Permanently’ Changed the Great Barrier Reef

SOURCE: Pacific Standard DATE: March 16, 2017 AUTHOR: Eric Holthaus SNIP: Scientists speculate that the era of never-ending global coral bleaching may have already arrived, decades early. In a new study, published Wednesday as the cover story in the journal Nature, Hughes and his colleagues — the paper includes an astounding 45 co-authors — find that 91 percent of the Great Barrier Reef has bleached at least once during three major bleaching events in 1998, 2002, and 2016. The most recent of these events — triggered in part by a strong El Niño — was so severe that there is no similar analog in the thousands of years of ancient coral cores scientists use to study past climates. The study’s authors further argue that, over the last decade or two, global warming has changed conditions on the Great Barrier Reef so quickly that old conservation methods no longer work. Earlier this month, the authority that oversees the Great Barrier Reef discovered that it has begun bleaching again — just months after its worst bleaching event on record. Quick-growing corals in the Great Barrier Reef require 10 to 15 years to fully recover from a mass-bleaching event, and long-lived species may require many decades. That kind of breathing room is “no longer realistic,” according to Hughes and his colleagues, as long as global temperatures keep...
The world’s oceans are storing up staggering amounts of heat — and it’s even more than we thought

The world’s oceans are storing up staggering amounts of heat — and it’s even more than we thought

SOURCE: The Washington Post DATE: March 10, 2017 SNIP: The world is getting warmer every year, thanks to climate change — but where exactly most of that heat is going may be a surprise. As a stunning early spring blooms across the United States, just weeks after scientists declared 2016 the hottest year on record, it’s easy to forget that all the extra warmth in the air accounts for only a fraction of the heat produced by greenhouse gas emissions. In fact, more than 90 percent of it gets stored in the ocean. And now, scientists think they’ve calculated just how much the ocean has warmed in the past few decades. A new study, out Friday in the journal Science Advances, suggests that since 1960, a staggering 337 zetajoules of energy — that’s 337 followed by 21 zeros — has been added to the ocean in the form of heat. And most of it has occurred since 1980. The new value is a number that significantly exceeds previous estimates, Trenberth [Kevin Trenberth, a senior scientist at the National Center for Atmospheric Research] noted. Compared with ocean warming estimates produced by the Intergovernmental Panel on Climate Change, the new values are about 13 percent...