Category: coral reefs

More coral bleaching forecast this summer

Relentless ocean heat takes toll on reefs worldwide

Parts of the Northern Hemisphere oceans could once again be hit by coral reef bleaching this summer.
Bleaching caused by global warming is overwhelming many coral reefs. Photo via NOAA.

Staff Report

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.

 

 

 

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Sea level rise overwhelming some coral reefs

A sea turtle swims lazily along a coral reef in Hawaii, trailed by tropical fish. (Photo by Kosta Stamoulis, courtesy Oregon State University via Flickr.)

Seafloor erosion outpacing expectations

Staff Report

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”

Mass coral bleaching likely along northern Great Barrier Reef

Extensive stand of severely bleached coral at Lisianski Island in the Papahanaumokuakea Marine National Monument in Hawaii, documented during an August 2014 NOAA research mission. (Credit: NOAA).

Scientists are currently mapping the biological damage caused by global warming

Staff Report

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”

Can ‘supersites’ anchor coral reef protection efforts?

Yellow tangs swim in a coral reef ecoystems.
Yellow tangs swim in a coral reef ecoystems. Photo courtesy NOAA.

Study says 90 percent of all predatory fish species have been lost from Caribbean coral reefs

Staff Report

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?”

Coral bleaching threat persists in Southern Hemisphere

Uptick in tropical cyclones intensifies impacts, hampers recovery

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A recent update from NOAA’s coral watch program shows that many reefs in the Southern Hemisphere face potential bleaching events in the next several months.

Staff Report

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.

New research published in the journal Global Change Biology looked at whether predicted increases in cyclone intensity might change the nature of coral reefs, using the Great Barrier Reef as a test case with reef data going back to 1996, as well as information gathered during recent tropical cycles. The study found that tropical cyclones between 2009 and 2014  caused record destruction of corals. Continue reading “Coral bleaching threat persists in Southern Hemisphere”

Australian scientists say parts of Great Barrier Reef survived bleaching

Northern section hammered by warm ocean temperatures

This NASA photo shows southern portion of the reef adjacent to the central Queensland coast
This NASA photo shows a southern portion of the Great Barrier Reef adjacent to the central Queensland coast.

Staff Report

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.

In the hardest-hit area along a 700-kilometer section of the northern reef, an of 67 percent of shallow-water corals died in the last six to nine months. Farther south, over the vast central and southern regions of the Great Barrier Reef, the scientists were relieved to find a much lower death toll. Continue reading “Australian scientists say parts of Great Barrier Reef survived bleaching”

New surveys confirm Great Barrier Reef damage

Heat-driven coral bleaching continues to take a toll

Staff Report

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.

“Millions of corals in the north of the Great Barrier Reef died quickly from heat stress in March and since then, many more have died more slowly,” said Dr. Greg Torda whose team recently returned from re-surveying reefs near Lizard Island. Continue reading “New surveys confirm Great Barrier Reef damage”