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.
Activists plan lawsuit to win more environmental protection
Even with coral reefs around the world under the global warming gun, the U.S. Army Corps of Engineers is seeking approval for a controversial Florida dredging project that could smother parts of the only coastal barrier reef in the continental United States.
But a coalition of environmental and community groups have banded together to try and the the Corps to provide mandatory, common-sense protections for reefs near the Port Everglades dredging project near Fort Lauderdale. The project’s goal is to increase coastal access for larger ships. Continue reading “Florida harbor dredging threatens 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”→
Cuban coral reefs thought to be among region’s most pristine
Tourists won’t be the only beneficiaries of easing tensions between the U.S. and Cuba. Scientists working in the Caribbean will also be able to find new opportunities for collaboration, according to federal officials.
“Ocean currents know no boundaries,” said Billy Causey, regional director of NOAA’s Office of National Marine Sanctuaries‘ Southeast Atlantic, Gulf of Mexico and Caribbean region. “They’re a conveyor belt, moving important marine life between our countries. Working together will help us better preserve these natural resources to benefit people in both our countries,” Causey said.
‘If we don’t take action … coral reefs will not survive into the next century’
The most dangerous effects of global warming may still be decades away, but ocean scientists say that the buildup of carbon dioxide is already slowing down the growth of coral reefs. By simulating ocean acidification on a section of the Great Barrier Reef, the researchers showed that excess C02 in the atmosphere is affecting coral reefs.
“Our work provides the first strong evidence from experiments on a natural ecosystem that ocean acidification is already causing reefs to grow more slowly than they did 100 years ago,” said study lead author Rebecca Albright, a marine biologist in Carnegie’s Department of Global Ecology in Stanford, Calif. “Ocean acidification is already taking its toll on coral reef communities. This is no longer a fear for the future; it is the reality of today.” Continue reading “Study says ocean acidification has already slowed coral growth”→
“We’re maybe looking at a 2- to 2.5-year-long event. Some areas have already seen bleaching two years in a row,” said Mark Eakin, a biological oceanographer with the National Oceanic and Atmospheric Administration in College Park, Maryland, and coordinator of the agency’s Coral Reef Watch.
Scientists with Oregon State University studied the event and reported their findings in the journal Frontiers in Microbiology, explaining how their research is important in the context of an ongoing global coral reef bleaching event.
“This is bad news,” said Rebecca Vega-Thurber, an assistant professor of microbiology in the OSU College of Science and corresponding author on the study. “This bleaching event occurred in a very short period on a pristine reef. It may recover, but incidents like this are now happening more widely all around the world. This research suggests that viral infection could be an important part of the problem that until now has been undocumented, and has received very little attention,” she said. Continue reading “Scientists track viral outbreaks in coral reefs”→