Study identifies bleaching and mortality thresholds for imperiled coral reefs
The steady rise in ocean temperatures projected for the next few decades will put more and more corals at risk of bleaching, as the warm water simply overwhelms their thermal tolerance mechanisms.
Recent research along the Great Barrier Reef shows that corals have been able to survive past bleaching events because they were acclimated to warmer temperatures by being exposed to a pattern of gradually warming waters in the lead up to each episode. But global warming is likely to change that, the scientists said.
Before long, temperature increases of as little as 0.5 degrees Celsius may push many corals over the edge as the warm water causes them to expel the algae-like dinoflagellates that help keep them alive and give them their color.
Lead author Dr. Tracy Ainsworth from Coral CoE said bleaching is like a marathon for corals.
Australian scientists have closely tracked the status of reefs along their coastline for the past few months as it became evident that this year’s strong El Niño would raise ocean temperatures above the limit of what most corals species can survive, and the latest survey results confirm their worst fears. In a press release, the researchers said the impacts are still unfolding along the 2,300-long reef, with the worst damage to the central and northern sections. Continue reading “Global warming kills a third of Great Barrier Reef’s corals”→
Global warming impacts on reefs unfolding as projected
Global warming has been driving the worst and longest episode of coral reef bleaching on record, and the event is hitting the Great Barrier Reef especially hard. Australian scientists this week said their latest aerial surveys of more than 500 reefs show that the most pristine section of the Great Barrier Reef is currently experiencing the worst, mass bleaching event in its history, with the overwhelming majority of reefs being ranked in the most severe bleaching category.
The latest data from the Australian researchers confirms all the projections and worst fears that global warming will likely decimate most coral reefs worldwide. That, in turn, could affect entire ocean ecosystems, since reefs are the nurseries of the seas.
“This has been the saddest research trip of my life,” said Prof. Terry Hughes, with Australia’s National Coral Bleaching Taskforce. “Almost without exception, every reef we flew across showed consistently high levels of bleaching, from the reef slope right up onto the top of the reef. We flew for 4,000 kilometers in the most pristine parts of the Great Barrier Reef and saw only four reefs that had no bleaching. The severity is much greater than in earlier bleaching events in 2002 or 1998,” Hughes said. Continue reading “Australian scientists document massive coral bleaching along the Great Barrier Reef”→
Ancient climate clues warn about impacts of modern human activities
FRISCO — Turbulent seas, loaded with sediment and nutrients at the end of the last ice age likely set back growth of the Great Barrier Reef by centuries, according to scientists who recently took a close look at the reef’s biological history.
The findings are important because those environmental conditions are similar to what the Great Barrier Reef is experiencing today as a result of human activities, including the controversial coal port dredging that’s seen as a huge threat to Australia’s cherished ocean landmark. Continue reading “Trouble ahead for the Great Barrier Reef?”→
Australian study shows how recreational and commercial fishing affect reef health
FRISCO —Biologists have long known that removing key predators from the food chain has top-down impacts on ecosystems, and a new study by Australian researchers shows the same holds true for coral reefs. Fishing, they say, is having a big impact on the Great Barrier Reef.
Australian scientists offer common-sense plan to restore coral reef ecosystem
FRISCO — After a 40-year span when the Great Barrier Reef lost half its coral cover, and with global warming looming for the future, Australian scientists say fundamental changes are needed to protect the reef.
Study shows rebound of coral trout in no-fishing zones
FRISCO — Long-term monitoring in the Great Barrier Reef ecosystem shows that marine protection pays off in a big way, as scientists said that coral trout biomass has more than doubled since the 1980s in the green zones.
The trout in the protected reserves are bigger and more abundant than those in fished “blue zones” of the Great Barrier Reef Marine Park, and they are also better able to cope with cyclone damage, according to a long-term study published today in Current Biology. Similar approaches may be beneficial for coral reefs around the world, the researcher concluded. Continue reading “Protected zones pay off for Great Barrier Reef”→