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Carbon Dioxide a Danger to Sea Life
Nearly half of the carbon dioxide released by human activity since the start of the Industrial Revolution has wound up in the oceans, changing the chemistry of the water on a vast scale and possibly endangering sea life.
That's the conclusion of two studies, released Thursday, that attempt to document this change for the first time. They are based on more than 72,000 measurements of carbon in the oceans taken during two international surveys from 1989-1998.
If the trend continues -- and scientists have every reason to think it will, with fossil-fuel emissions growing exponentially -- ocean waters will become ever more acidic, compromising the ability of organisms to make the protective shells they need to survive, researchers say.
Although the impacts on ecosystems are unknown, they could be enormous, given the huge numbers of shelled creatures that live in the seas. They range from floating one-celled plants and animals that are the basis of the food chain to coral reefs and bottom-dwelling clams.
The results are "a wake-up call," said Peter Brewer, an pioneering expert in ocean chemistry at the Monterey Bay Aquarium Research Institute, who was not involved in the study. "The numbers are crystal clear. The analysis is impeccable. There is no uncertainty about this."
Until recently, most of the concern over carbon dioxide and other greenhouse gases has focused on the atmosphere. These gases trap heat against the surface, much as a greenhouse window does, in a process that is expected to change climate in dramatic and unpredictable ways.
Although scientists have known for a long time that the oceans also absorb a lot of carbon dioxide, for the most part this was considered good because it slows climate change.
"Now people are coming to the realization that carbon dioxide is a pollutant" that can damage marine life, said Ken Caldeira, a chemical oceanographer with Lawrence Livermore National Laboratory who also was not involved in the study. "By driving our cars around we're polluting the ocean."
The new study, by a group led by Richard A. Feely and Christopher L. Sabine of the National Oceanic and Atmospheric Administration in Seattle, appears in today's issue of the journal Science.
It's based on data gathered by hundreds of scientists during 95 cruises of the world's oceans. Gathering and analyzing the information took 15 years. The researchers had to figure out how much of the carbon in the water was natural and how much came from artificial sources.
Seawater naturally absorbs carbon dioxide gas from the atmosphere. Once in the water, the gas is converted to carbonic acid. In turn, the acid sops up another compound, carbonate, that creatures need to make shells.
If nothing is done to curb the release of carbon dioxide into the atmosphere, the researchers said, surface waters will continue to become more acidic and the amount of carbonate available for shell-making will drop by 55 percent from pre-industrial levels within a century.
Most of these studies were carried out under extreme conditions that are not expected to develop for a century or more. Researchers say more work is needed to understand what may be happening to ocean plants and animals under today's chemical conditions.
In May, about 120 scientists met in Paris to report their latest results on the impacts of putting massive amounts of carbon into the oceans.
"There will be ecological losers on a very large scale," Brewer wrote in a summary of the meeting. "Viable coral reef systems will very possibly vanish." He said the best scientific information indicates that "these impacts of a high carbon dioxide ocean are real, and are measurable today," and will change the ecology of the seas in ways not yet understood.
Nearly half of the carbon dioxide released by human activity since the start of the Industrial Revolution has wound up in the oceans, changing the chemistry of the water on a vast scale and possibly endangering sea life.
That's the conclusion of two studies, released Thursday, that attempt to document this change for the first time. They are based on more than 72,000 measurements of carbon in the oceans taken during two international surveys from 1989-1998.
If the trend continues -- and scientists have every reason to think it will, with fossil-fuel emissions growing exponentially -- ocean waters will become ever more acidic, compromising the ability of organisms to make the protective shells they need to survive, researchers say.
Although the impacts on ecosystems are unknown, they could be enormous, given the huge numbers of shelled creatures that live in the seas. They range from floating one-celled plants and animals that are the basis of the food chain to coral reefs and bottom-dwelling clams.
The results are "a wake-up call," said Peter Brewer, an pioneering expert in ocean chemistry at the Monterey Bay Aquarium Research Institute, who was not involved in the study. "The numbers are crystal clear. The analysis is impeccable. There is no uncertainty about this."
Until recently, most of the concern over carbon dioxide and other greenhouse gases has focused on the atmosphere. These gases trap heat against the surface, much as a greenhouse window does, in a process that is expected to change climate in dramatic and unpredictable ways.
Although scientists have known for a long time that the oceans also absorb a lot of carbon dioxide, for the most part this was considered good because it slows climate change.
"Now people are coming to the realization that carbon dioxide is a pollutant" that can damage marine life, said Ken Caldeira, a chemical oceanographer with Lawrence Livermore National Laboratory who also was not involved in the study. "By driving our cars around we're polluting the ocean."
The new study, by a group led by Richard A. Feely and Christopher L. Sabine of the National Oceanic and Atmospheric Administration in Seattle, appears in today's issue of the journal Science.
It's based on data gathered by hundreds of scientists during 95 cruises of the world's oceans. Gathering and analyzing the information took 15 years. The researchers had to figure out how much of the carbon in the water was natural and how much came from artificial sources.
Seawater naturally absorbs carbon dioxide gas from the atmosphere. Once in the water, the gas is converted to carbonic acid. In turn, the acid sops up another compound, carbonate, that creatures need to make shells.
If nothing is done to curb the release of carbon dioxide into the atmosphere, the researchers said, surface waters will continue to become more acidic and the amount of carbonate available for shell-making will drop by 55 percent from pre-industrial levels within a century.
Most of these studies were carried out under extreme conditions that are not expected to develop for a century or more. Researchers say more work is needed to understand what may be happening to ocean plants and animals under today's chemical conditions.
In May, about 120 scientists met in Paris to report their latest results on the impacts of putting massive amounts of carbon into the oceans.
"There will be ecological losers on a very large scale," Brewer wrote in a summary of the meeting. "Viable coral reef systems will very possibly vanish." He said the best scientific information indicates that "these impacts of a high carbon dioxide ocean are real, and are measurable today," and will change the ecology of the seas in ways not yet understood.
That ain't too cool. :?
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