Archive for May, 2008

Carbon emissions, carbon-rich waters drive up ocean acidity

Manmade carbon emissions and the seasonal upwelling of naturally carbon-rich waters are driving up the acidity of the shallow ocean just off the West Coast, a team of researchers from Oregon and elsewhere has found, posing a threat to shellfish, sea urchins and smaller shell-forming creatures that serve as food for young salmon.

Their study, published online today in the journal Science Express, for the first time documents high acidity in the shallow nearshore waters of the West Coast’s fruitful continental shelf, the researchers said. It expands on global research into ocean acidification, which has tied increasing acidity levels to the ocean’s absorption of manmade carbon dioxide emissions and warned that it could decimate coral reefs.
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EPOCA: ocean acidification and its impact on ecosystems

Paris, May 26, 2008

Emissions of carbon dioxide (CO2) through human activities have a well known impact on the Earth’s climate. What is not so well known is that the absorption of this CO2 by the oceans is causing inexorable acidification of sea water. But what impact is this phenomenon having on marine organisms and ecosystems? This is a question to which researchers have few answers as yet. That is why the European Union has recently given its support to EPOCA, the European Project on Ocean Acidification, which will be launched in Nice (France) on 10 June 2008.
EPOCA’s goal is to document ocean acidification, investigate its impact on biological processes, predict its consequences over the next 100 years, and advise policy-makers on potential thresholds or tipping points that should not be exceeded. The project is coordinated by Jean-Pierre Gattuso, a CNRS researcher at the Oceanography Laboratory at Villefranche-sur-mer (LOV(1)), and brings together a consortium of 27 partners, including CNRS and the French Atomic Energy Agency (CEA), from 9 countries. Many of the leading oceanographic institutions across Europe and more than 100 permanent scientists are involved. The budget is €16.5 million over 4 years, including €6.5 million from the European Commission.
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Evidence for upwelling of corrosive “acidified” water onto the continental shelf

The absorption of atmospheric carbon dioxide into the ocean lowers the pH of the waters. This so-called ocean acidification could have important consequences for marine ecosystems. In order to better understand the extent of this ocean acidification in coastal waters, we conducted hydrographic surveys from central Canada to northern Mexico. We observed seawater that is undersaturated with respect to aragonite upwelling onto large portions of the continental shelf, reaching depths of approximately 40 to 120 m along most transect lines and all the way to the surface on one transect off northern California. While seasonal upwelling of the undersaturated waters onto the shelf is a natural phenomenon in this region, the ocean uptake of anthropogenic CO2 has increased the areal extent of the affected area.
Continue reading ‘Evidence for upwelling of corrosive “acidified” water onto the continental shelf’

Ocean acidification may increase calcification rates, but at a cost

Ocean acidification is the lowering of pH in the oceans as a result of increasing uptake of atmospheric carbon dioxide. Carbon dioxide is entering the oceans at a greater rate than ever before, reducing the ocean’s natural buffering capacity and lowering pH. Previous work on the biological consequences of ocean acidification has suggested that calcification and metabolic processes are compromised in acidified seawater. By contrast, here we show, using the ophiuroid brittlestar Amphiura filiformis as a model calcifying organism, that some organisms can increase the rates of many of their biological processes (in this case, metabolism and the ability to calcify to compensate for increased seawater acidity). However, this upregulation of metabolism and calcification, potentially ameliorating some of the effects of increased acidity comes at a substantial cost (muscle wastage) and is therefore unlikely to be sustainable in the long term.
Continue reading ‘Ocean acidification may increase calcification rates, but at a cost’

Ocean acidification – another undesired side effect of fossil fuel-burning

Up to now, the oceans have buffered climate change considerably by absorbing almost one third of the worldwide emitted carbon dioxide. The oceans represent a significant carbon sink, but the uptake of excess CO2 stemming from man’s burning of fossil fuels comes at a high cost: ocean acidification.
Up to now, the oceans have buffered climate change considerably by absorbing almost one third of the worldwide emitted carbon dioxide. The oceans represent a significant carbon sink, but the uptake of excess CO2 stemming from man’s burning of fossil fuels comes at a high cost: ocean acidification.

Research on ocean acidification is a newly emerging field and was one of the major topics at this year’s European Geosciences Union (EGU) General Assembly held in Vienna in April. The European Science Foundation EUROCORES (European Collaborative Research) programme EuroCLIMATE, which addresses in particular global carbon cycle dynamics, organized and co-sponsored several sessions on ocean acidification.
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Oceans under siege: Sunscreens add to toll on reefs

It is our task in our time and in our generation to hand down undiminished to those who come after us, as it was handed down to us by those who went before, that natural wealth and beauty which is ours.

— President Kennedy, dedication of National Wildlife Federation Building in 1961

While the world worries and debates about increasing carbon dioxide in our atmosphere, a more insidious and perhaps irreversible change threatens the oceans.

Like the air we breathe, oceans represent a dumping ground for the gases released when human beings burn fossil fuels. Marine waters have absorbed approximately half of the carbon dioxide released from industrialization, and the resulting phenomenon is termed ocean acidification.
Continue reading ‘Oceans under siege: Sunscreens add to toll on reefs’

A sprinkle of limestone could help oceans absorb CO2

Grind it down, pour in a sprinkle here and a dash there, and wait for results. That’s the recipe for helping the oceans to absorb more of our carbon dioxide emissions: add limestone. It may not only help reduce global warming but could even reinvigorate ailing coral reefs.

When atmospheric CO2 dissolves in the ocean, it reacts with carbonate ions in the surface waters to form bicarbonate ions. While this helps keep the acidity of the ocean constant, it lowers the concentration of carbonate ions. This makes the rise in atmospheric CO2 bad news for corals and other organisms which build their exoskeletons by absorbing carbonate ions along with calcium. Ultimately the oceans could also become less able to absorb atmospheric CO2, as there are fewer carbonate ions around to mop up the CO2.

Continue reading ‘A sprinkle of limestone could help oceans absorb CO2’

Marine ecosystems threatened by acidic oceans

Sea level rise and coral bleaching are known impacts of climate change on the oceans, but scientists worldwide are increasingly concerned about acidification of seawater, a subtler effect, but one that is much more damaging to the marine ecosystem and the human food chain.

“The current level of carbon dioxide [CO2] equivalent accumulation in the atmosphere is 430 parts per million [ppm]. If we allow business as usual at the current rate of CO2 emission over the next eight to ten years, we will exceed 500 ppm of CO2 by 2050 and coral reef ecosystems will be extensively and irreversibly damaged, while carbonate reefs will largely disappear,” World Bank marine biologist Marea Hatziolos said. In an attempt to understand ocean acidification and its impact on the marine ecology in Thailand, a team of scientists from Phuket is set to study the problem in preparation to address its effects on the ocean ecology and the human food chain.
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Ocean science experiment could fight acidification

As any good chemistry student knows, if something is too acidic, add a base. Could that be the solution to the problem of ocean acidification?

Danny Harvey of the University of Toronto wanted to check it out. In a new study, published in the Journal of Geophysical Research, he calculated the effect of dumping massive amounts — 4.4 billion tons per year — of powdered limestone, or calcium carbonate, into the ocean to counteract the acidification caused by increased atmospheric CO2 dissolving in the ocean.
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Echinoderms wasted by acid

The increasing acidity of the oceans, which can dissolve shells or skeletons, is a threat to many marine animals. Now, researchers have shown that a common and ecologically important echinoderm can survive the acid attack on its skeleton but only at the cost of its muscles. “The coping mechanism might be as much of a threat to survival” as acidity, says lead author Hannah Wood of the Plymouth Marine Laboratory in the United Kingdom. Experts say the finding points out the need to study the impact of growing acidity on whole organisms.
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Ocean acidification in the IPCC AR5 WG II

OUP book