Category: 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”

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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”

Bleaching risk on the rise for Great Barrier Reef corals

Global warming is likely to overwhelm corals'
Global warming is likely to overwhelm corals’ built-in thermal tolerance mechanisms within the next few decades, leading to more bleaching and mortality. Photo courtesy Dr. Peter Mumby.

Study identifies bleaching and mortality thresholds for imperiled coral reefs

Staff Report

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.

“When corals are exposed to a pre-stress period in the weeks before bleaching, as temperatures start to climb, this acts like a practice run and prepares the coral. Corals that are exposed to this pattern are then less stressed and more tolerant when bleaching does occur,” Ainsworth said. Continue reading “Bleaching risk on the rise for Great Barrier Reef corals”

Florida harbor dredging threatens corals

Mapping coral diseases is helping researchers determine the cause. Photo courtesy NOAA.
Mapping coral diseases is helping researchers determine the cause. Photo courtesy NOAA.

Activists plan lawsuit to win more environmental protection

Staff Report

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”