Coral decline warns of ocean changes: Australian scientists

A sharp slowdown in coral growth on Australia’s Great Barrier Reef since 1990 is a warning sign that precipitous changes in the world’s oceans may be imminent, scientists said Friday.

Strong evidence points to the cause being a combination of warmer seas and higher acidity from increased levels of atmospheric carbon dioxide, Australian Institute of Marine Science researchers reported.

Stunted Coral Highlights Troubling Ocean Trends

Coral in the Great Barrier Reef is showing significant signs of trouble, apparently the result of human activities.

Scientists say one species of coral is growing much more slowly than it was 15 years ago. If current trends continue, this species of coral could stop growing altogether by the middle of the century.

Scientists suspect that coral growth is being stunted by warmer ocean waters, as well as increasing acidity caused by carbon dioxide that’s entering the ocean as a result of fossil fuel combustion.

Slowing coral growth may spell disaster for Great Barrier Reef

Growth rates among corals on the Great Barrier Reef have slumped to their slowest in at least four centuries and growth is expected to cease within 26 years.

The process of calcification, which gives the reefs their structure and strength, has slowed by 14.2 per cent in less than 20 years, researchers in Australia have discovered.

The slowdown is so abrupt that they fear the natural process of reef-building will stop by 2050 and perhaps as early as 2035, when the Great Barrier Reef will start to fall apart.

Other reefs around the world are feared to be similarly affected, with disastrous implications for fish and other creatures. Global reef cover is already shrinking by 1 per cent annually.

Stress from changes in surface temperatures and an increase in acidity caused by more carbon dioxide being absorbed by the water were cited as the most likely causes.

Coral growth slows sharply on Great Barrier Reef

Coral growth since 1990 in Australia’s Great Barrier Reef has fallen to its lowest rate for 400 years, in a troubling sign for the world’s oceans, researchers said on Thursday.

This could threaten a variety of marine ecosystems that rely on the reef and signal similar problems for other similar organisms worldwide, Glen De’ath and colleagues at the Australian Institute of Marine Science said.

The Great Barrier Reef is the world’s largest coral expanse, and like similar reefs worldwide is threatened by climate change and pollution.

Ocean Acidification Hits Great Barrier Reef

Coral growth has been sluggish since 1990 due to an increase in both sea temperature and acidity as a result of global warming

The largest coral reef system in the world—and the biggest sign of life on Earth, visible from space—is not growing like it used to. A sampling of 328 massive Porites coral (large structures resembling brains that are formed by tiny polyps) from across the 133,000-square-mile (344,000-square-kilometer) reef reveals that growth of these colonies has slowed by roughly 13 percent since 1990.

The most likely reason is climate change caused by increasing carbon dioxide (CO2) and other greenhouse gases in the atmosphere, according to a new paper published today in Science.

Great Barrier Reef growing at slowest rate for 400 years

They are the rainforests of the sea, providing food and shelter for millions of marine creatures.

But now tropical coral reefs are facing a renewed – and hidden – threat from environmental change which is stunting their growth, claim scientists.

Researchers looking at the world’s biggest and best preserved reef – the Great Barrier Reef – found that it is growing at its slowest rate for at least 400 years.

While the damage is not visible to the naked eye scientists believe it is a “very worrying” indicator which could spell disaster for the biodiversity of the seas.

Slowdown of coral growth extremely worrying, say scientists

Coral growth across the Great Barrier Reef has suffered a “severe and sudden” slowdown since 1990 that is unprecedented in the last four centuries, according to scientists.

The researchers analysed the growth rates of 328 coral colonies on 69 individual reefs that make up the 1,250 mile-long Great Barrier Reef, off north-east Australia. They found that the rate at which the corals were laying down calcium in their skeletons dropped by 14.2% between 1990 and 2005.

Great Barrier Reef decline blamed on global warming

CORALS on the Great Barrier Reef are growing slower than at any time in at least 400 years and leading scientists are blaming climate change.

As a major study is being published in the US, scientists fear the reef is showing signs of mass coral bleaching, last seen in 2002.

Glenn De’ath, co-author of the research published in Science magazine, said the corals would stop growing altogether by 2050 if the trend identified in the study continued.

“When you disturb an ecosystem in this way, you get a cascading effect. You then get a chain reaction — the fish habitat is lost,” Dr De’ath said.

Coral study finds slowest growth in 400 years

ELEANOR HALL: The tipping point for catastrophic climate change is an issue of dispute between politicians and environmentalists.

But on the climate vulnerable Great Barrier Reef, researchers have been surprised to discover that a tipping point for coral growth has already been reached.

In the journal Science this morning they reveal that it was reached 18 years ago, as Nonee Walsh reports.

Calcification Rates Drop in Australian Reefs

Wall Street isn’t alone in suffering a steep downturn. A large-scale study in Australia’s Great Barrier Reef has revealed that the rate at which corals absorb calcium from seawater to calcify their hard skeletons has declined precipitously in the past 20 years, slowing coral growth. The report, on page 116, provides empirical data that fuels concerns that increased carbon dioxide in the air is putting these diverse marine ecosystems at risk (Science, 4 May 2007, p. 678). “This study has provided the first really rigorous snapshot of how calcification might be changing” as the ocean temperature and acidity rise, says marine biologist Ove Hoegh-Guldberg of the University of Queensland in Australia. “The results are extremely worrying.”

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