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  Yahoo News 6 Jul 06
Fossil fuels said to damage ocean life
By Randolph E. Schmid, AP Science Write

EurekAlert 5 Jul 06
Report Warns about Carbon Dioxide Threats to Marine Life
The National Center for Atmospheric Research and UCAR Office of Programs

BOULDER—Worldwide emissions of carbon dioxide from fossil fuel burning are dramatically altering ocean chemistry and threatening marine organisms, including corals, that secrete skeletal structures and support oceanic biodiversity. A landmark report released today summarizes the known effects of increased atmospheric carbon dioxide on these organisms, known as marine calcifiers, and recommends future research for determining the extent of the impacts.

"It is clear that seawater chemistry will change in coming decades and centuries in ways that will dramatically alter marine life," says Joan Kleypas, the report's lead author and a scientist at the National Center for Atmospheric Research (NCAR) in Boulder.

"But we are only beginning to understand the complex interactions between large-scale chemistry changes and marine ecology. It is vital to develop research strategies to better understand the long-term vulnerabilities of sensitive marine organisms to these changes."

The report, "Impacts of Ocean Acidification on Coral Reefs and Other Marine Calcifiers," warns that oceans worldwide absorbed approximately 118 billion metric tons of carbon between 1800 and 1994.

Oceans are naturally alkaline, and they are expected to remain so, but the interaction with carbon dioxide is making them less alkaline and more acidic. The increased acidity lowers the concentration of carbonate ion, a building block of the calcium carbonate that many marine organisms use to grow their skeletons and create coral reef structures.

"This is leading to the most dramatic changes in marine chemistry in at least the past 650,000 years," says Richard Feely, one of the authors and an oceanographer at NOAA's Pacific Marine Environmental Laboratory (PMEL) in Seattle.

The report follows a workshop funded by the National Science Foundation and the National Oceanic and Atmospheric Administration, and hosted by the U.S. Geological Survey Integrated Science Center in St. Petersburg, Florida.

Slowing skeletal growth

Experimental studies, such as those conducted by one of the report's authors, Chris Langdon at the University of Miami, show that coral calcification consistently decreases as the oceans become more acidic.

This means that these organisms will grow more slowly, or their skeletons will become less dense, a process similar to osteoporosis in humans.

As a result, reef structures are threatened because corals may be unable to build reefs as fast as erosion wears away the reefs. "This threat is hitting coral reefs at the same time that they are being hit by warming-induced mass bleaching events," Langdon says.

Mass bleaching occurs when unusually warm temperatures cause the coral to expel the colorful microscopic algae that provide the coral polyps with food.

Many calcifying organisms—including marine plankton such as pteropods, a planktonic marine snail—are affected by the chemistry changes. Shelled pteropods are an important food source for salmon, mackerel, herring, and cod. If calcifying organisms such as pteropods are unable to sustain their populations, many other species may be affected.

"Decreased calcification in marine algae and animals is likely to impact marine food webs and has the potential to substantially alter the biodiversity and productivity of the ocean," says Victoria Fabry of California State University, San Marcos, who is another of the report's authors.

Threats to major ecosystems

Several other major ecosystems that are supported by marine calcifiers may be particularly threatened by ocean acidification.

These include cold-water reefs, which are extensive structures that provide habitat for many important fish species, particularly in the coastal waters of Alaska.

The report outlines future research to understand this consequence of climate change. While scientists cannot yet fully predict how much marine calcification rates will change in the future, the report warns that the more critical question is: "What does this mean in terms of organism fitness and the future of marine ecosystems?"

Lisa Robbins of the U.S. Geological Service Center for Coastal and Watershed Studies and Chris Sabine of NOAA's Pacific Marine Environmental Laboratory also co-authored the report.

Yahoo News 6 Jul 06
Fossil fuels said to damage ocean life
By Randolph E. Schmid, AP Science Writer

WASHINGTON - Corals and other marine creatures are threatened by chemical changes in the ocean caused by the carbon dioxide from burning fossil fuels, a panel of scientists warned Wednesday.

Already blamed for a greenhouse effect warming of the climate, much of this added carbon dioxide is dissolving in the oceans, making them more acid.

Such a change can damage coral and other shells and sealife, according to the panel of researchers convened by the National Science Foundation, National Oceanic and Atmospheric Administration and U.S. Geological Survey.

"A most fundamental property of ocean chemistry, pH, is changing and will continue to change as long as CO2 emissions are increasing. That is not debatable," Joan Kleypas, the report's lead author and a scientist at the National Center for Atmospheric Research in Boulder, Colo., said in a briefing.

The pH scale measures how acid or alkaline a substance is, rating from 0 to 14 with 7 being neutral. The lower the number the more acid something is.

"In the oceans pH is a relatively constant property and it has not changed over time scales of hundreds of thousands and probably even millions of years," Kleypas said. "The pH changes that are occurring in the ocean today are truly extraordinary," she added.

The oceans are normally slightly alkaline. Their average surface pH was 8.2 in 1800 and is headed for a predicted 7.9 by the middle of this century, she said.

"But we are only beginning to understand the complex interactions between large-scale chemistry changes and marine ecology. It is vital to develop research strategies to better understand the long-term vulnerabilities of sensitive marine organisms to these changes," Kleypas said.

The researchers estimated that between 1800 and 1994 the world's oceans absorbed 118 billion metric tons of carbon, reducing the natural alkalinity of seawater. A metric ton is 2,205 pounds.

Richard Feely, an oceanographer at NOAA's Pacific Marine Environmental Laboratory in Seattle, said "this is leading to the most dramatic changes in marine chemistry in at least the past 650,000 years."

Chris Langdon at the University of Miami said studies show that coral calcification consistently decreases as the oceans become more acidic. That means these organisms will grow more slowly, or their skeletons will become less dense, a process similar to osteoporosis in humans.

That threatens reefs because corals may be unable to build reefs as fast as erosion wears away the reefs.
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To see the report: Impacts of Ocean Acidification on Coral Reefs and Other Marine Calcifiers
Related articles on Wild shores and Global warming and climate change
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