Kim Cobb, a marine scientist at the Georgia Institute of Technology, expected the coral to be damaged when she plunged into the deep blue waters off Kiritimati Island, a remote atoll near the center of the Pacific Ocean. Still, she was stunned by what she saw as she descended some 30 feet to the rim of a coral outcropping.
“The entire reef is covered with a red-brown fuzz,” Dr. Cobb said when she returned to the surface after her recent dive. “It is otherworldly. It is algae that has grown over dead coral. It was devastating.”
The damage off Kiritimati is part of a mass bleaching of coral reefs around the world, only the third on record and possibly the worst ever. Scientists believe that heat stress from multiple weather events including the latest severe El Niño, compounded by climate change, has threatened more than a third of Earth’s coral reefs. Many may not recover.
Coral reefs are the crucial incubators of the ocean’s ecosystem, providing food and shelter to a quarter of all marine species, and they support fish stocks that feed more than one billion people. They are made up of millions of tiny animals, called polyps, that form symbiotic relationships with algae, which in turn capture sunlight and carbon dioxide to make sugars that feed the polyps.
An estimated 30 million small-scale fishermen and women depend on reefs for their livelihoods, more than one million in the Philippines alone. In Indonesia, fish supported by the reefs provide the primary source of protein.
“This is a huge, looming planetary crisis, and we are sticking our heads in the sand about it,” said Justin Marshall, the director of CoralWatch at Australia’s University of Queensland.
Bleaching occurs when high heat and bright sunshine cause the metabolism of the algae — which give coral reefs their brilliant colors and energy — to speed out of control, and they start creating toxins. The polyps recoil. If temperatures drop, the corals can recover, but denuded ones remain vulnerable to disease. When heat stress continues, they starve to death.
Damaged or dying reefs have been found from Réunion, off the coast of Madagascar, to East Flores, Indonesia, and from Guam and Hawaii in the Pacific to the Florida Keys in the Atlantic.
The largest bleaching, at Australia’s Great Barrier Reef, was confirmed last month. In a survey of 520 individual reefs that make up the Great Barrier Reef’s northern section, scientists from Australia’s National Coral Bleaching Task Force found only four with no signs of bleaching. Some 620 miles of reef, much of it previously in pristine condition, had suffered significant bleaching.
In follow-up surveys, scientists diving on the reef said half the coral they had seen had died. Terry Hughes, the director of the Center of Excellence for Coral Reef Studies at James Cook University in Queensland, who took part in the survey, warned that even more would succumb if the water did not cool soon.
The Latest on: Coral bleaching
via Google News
The Latest on: Coral bleaching
- Biodiversity helps coral reefs thrive – and could be part of strategies to save themon June 25, 2019 at 5:48 am
In contrast, reefs that have been damaged by stresses such as coral bleaching events tend to become simplified, less diverse landscapes, often dominated by seaweeds. For our study we chose a reef ... […]
- Live imaging of Aiptasia larvae, a model system for coral and anemone bleaching, using a simple microfluidic deviceon June 25, 2019 at 3:17 am
Coral reefs are remarkably productive ecosystems, supporting approximately 9% of the ocean fish biomass and 25% of oceanic species diversity 1. Reef-building corals depend on an endosymbiotic ... […]
- Reports on coral bleaching causing griefon June 24, 2019 at 7:18 am
Over-hyped reporting of coral bleaching on the Great Barrier Reef raised awareness about climate change but could leave the public disaffected, unengaged, sceptical or disillusioned about how to ... […]
- Coral Bleaching Permanently Changes Reef Fish Communitieson June 21, 2019 at 5:04 am
An 18-year study revealed that repeated episodes of severe coral bleaching are permanently changing the diversity and structure of the marine communities they support. An international team of ... […]
- Coral bleaching causing permanent change to fish: Studyon June 20, 2019 at 3:45 am
Repeat coral bleaching caused due to rising sea temperatures has resulted in lasting changes to fish communities, according to a long-term study. In the Seychelles, large predator fish such as ... […]
- Half of corals survived bleaching in Chabahar Porton June 19, 2019 at 8:58 am
... nearly 43.8 percent of the corals bleached in Chabahar Port mostly species of staghorn coral and cauliflower coral survived bleaching. Last summer a vast bleaching event occurred in the area, the ... […]
- Changing how we predict coral bleachingon June 18, 2019 at 6:57 am
A remote sensing algorithm offers better predictions of Red Sea coral bleaching and can be fine tuned for use in other tropical marine ecosystems. Coral bleaching events may occur more frequently ... […]
- Coral bleaching causes a permanent change in fish lifeon June 18, 2019 at 12:07 am
Repeat coral bleaching caused by rising sea temperatures has resulted in lasting changes to fish communities, according to a new long-term study in the Seychelles. Large predator fish such as ... […]
- Underwater photographer captures rare footage of coral spawning six months early, and during the dayon June 16, 2019 at 11:07 pm
“Of course our beautiful Reef has seen better days, but it is definitely showing great signs of recovery in the areas affected by coral bleaching and weather damage in the past few years.” The ... […]
- 3D mapping from the air helps to save coral reefson June 16, 2019 at 4:12 pm
As the corals’ chemistry changes, so does their coloration. By monitoring this, scientists can now detect the warning signs of coral bleaching before it happens and help design management and ... […]
via Bing News