Tag Archives: Coral Reef

Coral Reefs Threatened by Changing Ocean Conditions

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Photograph: © SAF — Coastal Care

By © Woods Hole Oceanographic Institution;

The lowering of the ocean’s pH is making it harder for corals to grow their skeletons and easier for bioeroding organisms to tear them down. Erosion rates increase tenfold in areas where corals are also exposed to high levels of nutrients, according to a study published January 2015 in the journal Geology. As sea level rises, these reefs may have a harder time growing toward the ocean surface, where they get sunlight they need to survive.

The study, led by scientists at Woods Hole Oceanographic Institution (WHOI), highlights the multiple threats to coral reef ecosystems, which provide critical buffers to shoreline erosion, sustain fisheries that feed hundreds of millions of people, and harbor 25 percent of all marine species. And it points to a key management strategy that could slow reef decline: reducing the input of nutrient pollution to the coastal ocean from human activity such as runoff from sewers, septic tanks, roads, and fertilizers.

Corals make their skeletons out of calcium and carbonate ions from seawater, constructing massive colonies as large as cars and small houses. As the ocean absorbs excess carbon dioxide from fossil-fuel burning, it spurs chemical reactions that lower the pH of seawater, a process known as ocean acidification. The process removes carbonate ions, making them less available for corals to build skeletons.

“A healthy coral reef ecosystem exists in a constant and often overlooked tug-of-war. As corals build their skeletons up toward the sea surface, other organisms—mollusks, worms, and sponges—bore into and erode the skeletons to create shelters,” said lead author Thomas DeCarlo, a graduate student in the WHOI-MIT Joint Program in Oceanography, working in Anne Cohen’s lab at WHOI.

This process, called bioerosion, reduces skeletons to rubble, which is transported offshore during fierce storms or gradually dissolved in the sediments. On healthy reefs today, calcium carbonate production barely exceeds the loss by erosion, dissolution, and offshore transport. As a result of this delicate balance, coral reefs grow very slowly, if at all, when sea level is stable.

The new study shows that additional nutrients provide a dramatic boost for bioeroders that, combined with lower pH conditions, will tip this balance in favor of erosion. The bioeroders are filter feeders, sifting particles of food out of seawater. Nutrients spur the growth of plankton, supplying food for large populations of bioeroders that burrow into coral skeletons.

When corals and bioeroders are in balance, the former grow just fast enough to stay near the sea surface, while the latter are busily sculpting the coral skeletons into an intricate, three-dimensional habitat full of nooks and hiding places for fish, urchins, and other marine life.

In waters with fewer carbonate ions and more nutrients, corals may not be able to build new skeleton fast enough to keep pace with bioeroders cutting down the reef. The result would be “flatter” coral reefs with less of the three-dimensional structure responsible for the rich biodiversity found on coral reefs.

To conduct the study, the research team investigated coral reefs spanning the Pacific Ocean, from the west coast of Panama to Palau. The reefs also spanned a range of different naturally occurring pH and nutrient conditions in the ocean, including several reefs in seawater with pH levels today that are as low as those expected for much of the tropical ocean by 2100. That allowed the scientists to examine how bioeroders are affected by the isolated and combined influences of pH and nutrient conditions.

The scientists used underwater drills to collect cores of coral skeletons. They put the cores through the CAT scanner at the Computerized Scanning and Imaging Facility at WHOI to get 3-D images of tunnels and borings made by bioeroders with a resolution of about the width of a human hair. That allowed them to calculate precisely how much skeleton the bioeroders had removed.

The researchers found that relatively acidic (lower-pH) reefs were more heavily bio-eroded than their higher-pH counterparts. But their most striking finding was that in waters with a combination of high nutrient levels and lower-pH, bio-erosion is ten times higher than in lower-pH waters without high nutrient levels.

“The ocean will certainly absorb more CO2 over the next century, and ocean acidification is a global phenomenon that reefs cannot escape,” DeCarlo said. “But the encouraging news in our findings is that people can take action to protect their local reefs. If people can limit runoff from septic tanks, sewers, roads, farm fertilizers, and others sources of nutrient pollution to the coastal ocean, the bioeroders will not have such an upper hand, and the balance will tip much more slowly toward erosion and dissolution of coral reefs.”

Along with DeCarlo and Cohen, the team included Hannah Barkley (WHOI), Kathryn Shamberger (WHOI, now at Texas A&M University), Quinn Cobban (Falmouth Academy), Charles Young and Russell Brainard (NOAA), and Yimnang Golbuu (Palau International Coral Reef Center). The research was funded by the National Science Foundation, the Nature Conservancy, and the National Oceanic and Atmospheric Administration’s Coral Reef Conservation Program.

Original Article and Learn More, Woods Hole Oceanographic Institution

Coral Reveals Long-Term Link Between Pacific Winds, Global Climate

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French Polynesia. Photograph: © SAF — Coastal Care

Excerpts;

New research indicates that shifts in Pacific trade winds played a key role in twentieth century climate variation and are likely again influencing global temperatures. The study uses a novel method of analyzing coral chemistry to reveal winds from a century ago.

The finding gives support to the theory that strong Pacific trade winds are currently helping to prevent global temperatures from climbing, even as society continues to emit carbon dioxide and other greenhouse gases. When the winds weaken as part of a natural cycle, warming will likely resume once again, the authors say…

Read Full Article, Science Daily

Great Barrier Reef at Risk from Rushed Sediment Dumping Plan at Abbot Point

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The Great Barrier Reef extends for 2,000 kilometers along the northeastern coast of Australia. It is not a single reef, but a vast maze of reefs, passages, and coral cays. Photo source: ©© jamestee

Excerpts;

A plan to dump dredged sediment onto a sensitive wetlands area beside the Great Barrier Reef near Abbot Point would lead to much more slurry being pumped into the waters of the reef than officially estimated, a report has warned…

Read Full Article, Guardian UK

Abbot Point: Study on Dumping of Spoil in Wetlands Not Required, Guardian UK (10-29-2014)
The federal government has waived the need for a full environmental impact study into the dumping of dredging spoil onto sensitive wetlands under the plan to expand the Abbot Point coal port in Queensland…

Great Barrier Reef Authority Approves Dredging And Dumping To Expand Port, Guardian UK (01-31-2014)
The Great Barrier Reef Marine Park Authority has approved a proposal to dump dredge spoil (about 3 million cubic meters 106 million cubic feet) from the Abbot Point coal terminal expansion in the Marine Park area…

Great Barrier Reef Dredge Approval Was ‘Suicide’ For Reef Authority, Guardian UK (10-07-2014)

Cooking The Climate Wrecking The Reef:The Global Impact Of Coal Exports From Australia’s Galilee Bassin, Greenpeace (09-19-2012)
A coal basin near Australia’s Great Barrier Reef will rank among the world’s worst producers of carbon pollution if fully mined, Greenpeace said, as it warned of devastating consequences. ” Cooking The Climate Wrecking The Reef: The Global Impact Of Coal Exports From Australia’s Galilee Bassin”, is a Greenpeace Australia Report.

UN Climate Chief Calls on Coal Industry to Change, (11-18-2013)

10 steps to save the Great Barrier Reef, Guardian UK (10-27-2014)

Acidic Oceans Could Quiet Coral Reefs

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Photograph: © SAF — Coastal Care

Excerpts;

Scientists have been monitoring underwater sounds for decades, in part because sound propagates so efficiently underwater. But in the past 10 years, scientists have started exploring how sonic cues influence fish behavior and give a snapshot of reef health and biodiversity…

Read Full Article, Climate Central

Great Barrier Reef Dangers: Unesco Says Australia is Listening at Last

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Photograph: © SAF – Coastal Care

Excerpts;

The head of Unesco says the Australian government has started to listen to international concerns over the health of the Great Barrier Reef, raising hopes that it will avoid receiving an embarrassing “in danger” listing next year…

Read Full Article, Guardian UK

Great Barrier Reef Dredge Approval Was ‘Suicide’ For Reef Authority, Guardian UK (10-07-2014)

Cooking The Climate Wrecking The Reef:The Global Impact Of Coal Exports From Australia’s Galilee Bassin, Greenpeace (Uploaded 09-19-2012)

Scientists on NOAA-Led Mission Discover New Coral Species Off California

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This is a new species of white coral, found in an area known as The Football. Most likely it is closely related to gorgonian corals. NOAA.

By NOAA;

A NOAA-led research team has discovered a new species of deep-sea coral and a nursery area for catsharks and skates in the underwater canyons located close to the Gulf of Farallones and Cordell Bank national marine sanctuaries off the Sonoma coast.

In the first intensive exploration of California’s offshore areas north of Bodega Head, a consortium of federal and state marine scientists used small submersibles and other innovative technologies to investigate, film and photograph marine life that has adapted to survive in offshore waters reaching 1,000 feet deep.

The exploration took place in September on NOAA’s R/V Fulmar and focused on two main sites: the head waters of Bodega Canyon and “the Football” – an area west of Salmon Creek and north of the canyon nicknamed for its oval shape. Prior to this expedition, scientists knew little about these areas except that they were thought to contain nutrient-rich and biologically diverse marine life.

After multiple dives, the research team made two significant discoveries — hundreds of skate egg cases on the seafloor, and in bundles on the rocks surrounding a catshark nursery area.
“This is a highly unusual nursery because rarely, if ever, are shark nurseries in the same area as skate nurseries,” said Peter Etnoyer, a deep-sea biologist at NOAA’s National Centers for Coastal Ocean Science.

One significant discovery was by made by a second team on the mission, led by California Academy of Sciences’ Gary Williams, who found corals approximately 600 feet deep that are a new species of deep-sea coral from the Leptogorgia genus.

“Deep-sea corals and sponges provide valuable refuge for fish and other marine life,” said Maria Brown, Farallones sanctuary superintendent. “Data on these life forms helps determine the extent and ecological importance of deep-sea communities and the threats they face. Effective management of these ecosystems requires science-based information on their condition.”

In addition to the discoveries, the research team also conducted video surveys of areas that previously were documented only through sonar imaging.

“The video surveys from this research mission verified the extent of rocky habitat estimated from sonar data collected several years ago, and the quality of rocky habitat in some areas exceeded expectations,” said Guy Cochrane, a U.S. Geological Survey geophysicist.

Submarine canyons, such as Bodega Canyon, extend from the continental shelf to the deep sea – making their exploration a difficult but worthwhile endeavor. The canyons are important because they act as a refuge for important species of fish and provide a habitat for sensitive species of deep water corals and sponges.

“Surveys of the seafloor in these waters reveal an abundance and diversity of life in new habitats,” said Danielle Lipski, Cordell Bank National Marine Sanctuary research coordinator and expedition leader. “This work helps inform our knowledge and understanding of the deep sea ecosystems north of Cordell Bank and Gulf of the Farallones national marine sanctuaries, areas that are extremely important to the ocean environment.”
The research expedition was made possible by partnerships and collaboration among government and academic partners including NOAA’s Office of National Marine Sanctuaries, NOAA National Center for Coastal Ocean Science’s, Gulf of the Farallones and Cordell Bank national marine sanctuaries, the U.S. Geological Survey and the California Academy of Sciences.

The U.S. Geological Survey serves the nation by providing reliable scientific information to describe and understand the Earth; minimize loss of life and property from natural disasters; manage water, biological, energy, and mineral resources; and enhance and protect our quality of life.

The California Academy of Sciences is a world-class scientific and cultural institution based in San Francisco. Its mission is to explore, explain and protect the natural world.

Original Article, NOAA

Belize Fights to Save a Crucial Barrier Reef

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Photograph: © SAF — Coastal Care

Excerpts;

Home to the second longest barrier reef in the world and the largest in the Western Hemisphere, which provides jobs in fishing, tourism and other industries which feed the lifeblood of the economy, Belize has long been acutely aware of the need to protect its marine resources from both human and natural activities…

Read Full Article, IPS News