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.
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”→
FRISCO — Ocean researchers have updated their warnings of potential coral reef bleaching based on unusually warm ocean temperatures across the north Pacific, equatorial Pacific, and western Atlantic oceans this summer.
Scientists with NOAA’s coral reef watch say they expect bleaching of corals on Northern Hemisphere reefs through October, potentially leading to the death of corals over a wide area and affecting the long-term supply of fish and shellfish.
FRISCO — Even without a surge of El Niño ocean heat, there was widespread coral bleaching across parts of the Pacific Ocean and the Caribbean this past summer.
Reefs in the Florida Keys saw their worst bleaching episode since 1997-1999, when a major El Niño was followed by strong La Niña conditions, NOAA scientists reported recently. The surprising intensity of bleaching across multiple ocean basins in 2014 has scientists wondering what to expect in 2015, when El Niño is forecasted to finally develop. Continue reading “NOAA reports major coral bleaching in 2014”→