Archive for February, 2007

CO2 may reduce mussel, oyster populations

A Dutch-led study suggests the Earth`s increasing carbon dioxide levels might result in significant losses of the world`s mussels and oysters.The researchers say recent experiments show the calcification rates of two types of mollusks kept in closed laboratory environments declined linearly with increasing levels of carbon dioxide in the air.

Frederic Gazeau at the Netherlands Institute of Ecology and French colleagues studied calcification rates of edible mussels and Japanese oysters. They determined mussel and oyster calcification might decrease by 25 percent and 10 percent, in that order, by the end of the century.

Since the species represent a large part of worldwide aquaculture production, the scientists say the resulting population decrease will potentially influence coastal biodiversity and ecosystem function, as well as lead to significant economic loss.

The study appears in the journal Geophysical Research Letters. Press release.

What Corals Are Dying to Tell Us about CO2 and Ocean Acidification

What Corals Are Dying to Tell Us about CO2 and Ocean Acidification

Speaker: Ken Caldeira, Ph.D.
Dept. of Global Ecology, The Carnegie Institution

Monday, March 5, 2007 5:30 PM. Smithsonian National Museum of Natural History. Link.

Scientist fears CO2 will kill oceans in decades

Unless we halt completely the emission of carbon dioxide from the world’s energy systems, we risk an oceanic catastrophe worse than the one associated with the disappearance of the dinosaurs.That’s the message a chemical oceanographer and environmental scientist intends to deliver to a conference on the future of the world’s oceans today at the University of Victoria.

Ken Caldeira, who teaches out of the Carnegie Institution at Stanford University in California, says the level of acidification caused by dumping hundreds of billions of tonnes of carbon dioxide into the world’s oceans is so great it could cause a major disruption on par with, or worse than, the sudden dumping of sulphuric acid into the oceans 65 million years ago when an asteroid slammed into the Earth’s surface.

Vancouver Sun, 22 February 2007. Article.

An estimate of anthropogenic CO2 inventory from decadal changes in oceanic carbon content

Increased knowledge of the present global carbon cycle is important for our ability to understand and to predict the future carbon cycle and global climate. Approximately half of the anthropogenic carbon released to the atmosphere from fossil fuel burning is stored in the ocean, although distribution and regional fluxes of the ocean sink are debated. Estimates of anthropogenic carbon (Cant) in the oceans remain prone to error arising from (i) a need to estimate preindustrial reference concentrations of carbon for different oceanic regions, and (ii) differing behavior of transient ocean tracers used to infer Cant. We introduce an empirical approach to estimate Cant that circumvents both problems by using measurement of the decadal change of ocean carbon concentrations and the exponential nature of the atmospheric Cant increase. In contrast to prior approaches, the results are independent of tracer data but are shown to be qualitatively and quantitatively consistent with tracer-derived estimates. The approach reveals more Cant in the deep ocean than prior studies; with possible implications for future carbon uptake and deep ocean carbonate dissolution. Our results suggest that this approach applied on the unprecedented global data archive provides a means of estimating the Cant for large parts of the world’s ocean.

Tanhua T., Körtzinger A., Friis K., Waugh D. W., and Wallace D. W. R., 2007. An estimate of anthropogenic CO2 inventory from decadal changes in oceanic carbon content. Proceedings of the National Academy of Science of the USA. doi:0.1073/pnas.0606574104. Article.

It’s inconvenient, but it’s true – 24 Feb 2007 – Climate change news – NZ Herald

New in this year’s report is concern about how increasing atmospheric carbon dioxide concentrations leads to increasing acidification of the ocean. Projections based on the emissions scenarios give reductions in average global surface ocean pH (the lower the pH, the more acidic) of between 0.14 and 0.35 units over the 21st century, adding to the present decrease of 0.1 units since pre-industrial times.

The New Zealand Herald, 27 February 2007. Article.

Southern Ocean being “strangled” by greenhouse gases

The pristine Southern Ocean, which swirls around the Antarctic and absorbs vast amounts of carbon dioxide from the atmosphere, is slowly losing a fight against industrial gases responsible for global warming, scientists say.

The Southern Ocean’s unique wind and storm conditions make it the world’s greatest carbon “sink”; the earth’s oceans absorb a third of the carbon dioxide in the atmosphere, and the Southern Ocean absorbs a third of that.

But the waters that surround Antarctica are becoming more acidic as they absorb increasing amounts of carbon dioxide produced by nations burning fossil fuels such as oil, coal and natural gas.

Reuters, 22 February 2007. Interview.

Signs of life out there, disaster back here

Unless we halt completely the emission of carbon dioxide from the worlds energy systems, we risk an oceanic catastrophe worse than the one associated with the disappearance of the dinosaurs.

Thats the message a chemical oceanographer and environmental scientist intends to deliver to a conference on the future of the worlds oceans today at the University of Victoria.

The Vancouver Sun
, 22 February 2007. Article

Gene chips forecast ecological impacts of climate change

(San Francisco, Calif.) –– Gretchen Hofmann, an associate professor of biology at the University of California, Santa Barbara, will present a talk about the use of technologies in molecular biology to assess climate-change related impacts on marine invertebrates at the annual meeting of the American Association for the Advancement of Science in San Francisco on Sunday, Feb. 18.

Her research centers on sea urchins and mussels, important members of marine ecosystems. The main focus will be on finding ways to assess the effects of temperature stress and low pH, due to ocean acidification, on adults and early developmental stages of marine invertebrates.

EurekaAlert, 18 February 2007. Press release.

Acid Oceans Threatening Marine Food Chain, Experts Warn

The world’s oceans are turning acidic due to the buildup of carbon dioxide (CO2) in the atmosphere, and scientists say the effects on marine life will be catastrophic.

National Geographic News, 17 February 2007. Article.

CO2 being pushed deep into the oceans

Atmospheric carbon dioxide is being pushed deeper into the oceans than previously thought, according to researchers.
The findings mean the oceans may continue to absorb human emissions of the greenhouse gas more rapidly and for longer, they say, reducing their impact on global warming. But the research is bad news for the marine organisms that are already suffering from ocean acidification.
Higher levels of CO2 in the atmosphere, caused largely by industrial activities, push the greenhouse gas into ocean waters. Although this process is fairly well understood, scientists have only estimates of the depth at which CO2 from human activities is stored in the oceans.
“Previous estimates, based on educated assumptions about what the pre-industrial oceans looked like, suggested that in the high latitudes of the North Atlantic, anthropogenic CO2 was not found below 2500 metres,” says Douglas Wallace of the University of Kiel, Germany.
Wallace and colleagues have now published the first measurements showing the location of CO2 from human activities in the North Atlantic. They used data collected during a research cruise in 1981 as a baseline, and then returned to exactly the same sampling locations in 2004.
“This revealed quite large changes in the CO2 in very deep water, between 3000 m and 5000 m,” Wallace told New Scientist.

New Scientist Environment, 12 February 2007. Article.


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