Relentless ocean heat takes toll on reefs worldwide
There’s been little let-up in the global wave of coral bleaching that’s been ongoing in various parts of the world since 2014, according to an update from NOAA’s Coral Reef Watch program. To date, the bleaching is the most widespread and damaging on record, including mass bleaching in areas where it’s never been seen before — the northern Great Barrier Reed, Kiribati and Jarvis Island.
And more of the same is expected in in the next few months as the Northern Hemisphere moves toward summer. Based on forecasts for the next two to three months, bleaching is likely in the eastern Pacific. Widespread coral bleaching with significant mortality continues in the Samoas (where bleaching of both shallow and deeper corals has now been confirmed) but is expected to dissipate shortly.
After extensive damage to the Great Barrier Reef, ocean temperatures finally cooled of in April, giving a respite to the corals that survived. Similarly, the corals around Florida also got some relief in the past few months. Get the full update at the NOAA coral reef watch page.
Coral reefs aren’t just threatened by pollution, ocean acidification and over-heated ocean temperatures. In some places they are being undermined by erosion of the seafloor, U.S. Geological Survey scientists said in a new study that looked at reefs in Florida, the Caribbean and Hawaii.
In the five study sites, the reefs can’t keep pace with sea level rise. As a result, coastal communities protected by the reefs are facing increased risks from storms, waves and erosion.
The degradation of reefs and the subsiding seafloor go hand-in-hand, as sand and other sea floor materials have eroded over the past few decades. In the waters around Maui, the sea floor losses amounted to 81 million cubic meters of sand, rock and other material – about what it would take to fill up the Empire State Building 81 times, the researchers calculated. Continue reading “Sea level rise overwhelming some coral reefs”→
Scientists are currently mapping the biological damage caused by global warming
At the end of eastern Australia’s long, hot summer, ocean scientists are once again seeing devastating coral die-backs in the northern reaches of the Great Barrier Reef. Over the next few weeks, they’ll venture underwater to study how the coral communities responded to a second straight year of overheated water.
When temperatures pass a threshold, the coral expels its symbiotic algal partner, leaving underwater wastelands of white-washed reefs. The scientists will also use survey flights above the reef, and even satellite imaging as they mobilize to document one of global warming’s most devastating impacts. There has been a prolonged global mass bleaching under way for the past year, and climate researchers say nearly all the world’s corals will be at risk by mid-century under projected global temperature increases. Continue reading “Mass coral bleaching likely along northern Great Barrier Reef”→
Study says 90 percent of all predatory fish species have been lost from Caribbean coral reefs
Not all Caribbean reefs are created equal, say researchers with the University of North Carolina at Chapel Hill, who recently identified reef areas they are calling “supersites”that could help restore populations of predatory fish needed maintain an ecological balance.
That’s the good news. The bad news is their study also shows that up to 90 percent of predatory fish are gone from Caribbean coral reefs. The research suggests that these supersites should be prioritized for protection and could serve as regional models showcasing the value of biodiversity for tourism and other uses. Continue reading “Can ‘supersites’ anchor coral reef protection efforts?”→
Uptick in tropical cyclones intensifies impacts, hampers recovery
Along with the widely reported bleaching threat from over-heated oceans, coral reefs in many parts of the world also may have to cope with intensifying tropical storms, which could make it even more difficult for them to survive the Anthropocene.
Northern section hammered by warm ocean temperatures
Australian researchers this week released results of their latest Great Barrier Reef surveys, concluding that huge swaths of coral died in the past year under the onslaught of an ocean heatwave that led to widespread coral bleaching.
A new survey of the Great Barrier Reef shows that an ocean heat wave that peaked last March killed up to 95 percent of corals in some parts of the northern reef. And in the aftermath of the worst coral-bleaching event on record, predatory snails are now taking on toll on the remaining corals.
According to the ARC Centre of Excellence for Coral Reef Studies, researchers recently returned to 83 reefs they surveyed at the height of the bleaching event.