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May 23, 2008

SEAS OFF WEST COAST VERY ACIDIC, STUDY WARNS

[Rachel's introduction: The Pacific Ocean is growing more acidic,
posing a threat to marine life, because of carbon dioxide entering
the atmosphere. The problem is at least 50 years more advanced than
scientists had predicted.]

By the Associated Press

Waters along North America's Pacific coast are becoming more acidic,
posing a threat to marine life, federal scientists reported Friday
-- adding that while that fits global warming scenarios, no one had
expected the acidification to happen so soon.

"We did not expect to see this extent of ocean acidification until the
middle to the end of the century," said study co-author Chris Sabine.

"Our results show for the first time that a large section of the North
American continental shelf is impacted by ocean acidification," the
experts wrote in the study published in the peer-reviewed journal
Science.

Acidification describes the process, natural or manmade, of ocean
water becoming corrosive as a result of carbon dioxide being absorbed
from the atmosphere.

The researchers said anthropogenic, or manmade, emissions of carbon
dioxide are likely to blame since the acidified water that is being
"upwelled" seasonally from the deeper ocean is from the last 50 years,
a period when the burning of fossil fuels raised CO2 levels
dramatically.

"Other continental shelf regions may also be impacted where
anthropogenic CO2-enriched water is being upwelled onto the shelf,"
they concluded.

Threat 'right now'

"Ocean acidification may be seriously impacting marine life on our
continental shelf right now," study co-author Richard Feely said in a
statement released by the National Oceanic and Atmospheric
Administration, which co-sponsored the study along with NASA and the
National Science Foundation.

Feely, a NOAA oceanographer, noted that while the ability of oceans to
absorb carbon dioxide helps mitigate warming, "the change in the ocean
chemistry affects marine life, particularly organisms with calcium
carbonate shells, such as corals, mussels, mollusks, and small
creatures in the early stages of the food chain."

NOAA echoed the experts' findings. "Acidification of the Earth's ocean
water could have far-reaching impacts on the health of our near-shore
environment, and on the sustainability of ecosystems that support
human populations," said NOAA assistant administrator Richard Spinrad.

"This research is vital to understanding the processes within the
ocean, as well as the consequences of a carbon-rich atmosphere," he
added.

The team compiled data from 13 survey lines dropped last summer and
stretching from the waters of central Canada to northern Mexico. They
measured pH levels in seawater to detect acidification, and found
lower levels were much closer to the surface than researchers had
predicted.

Previous studies found acidification at deeper depths farther from
shore. The researchers said the acidified water appears to well up in
spring and summer, when winds bring CO2-rich water up from depths of
about 400-600 feet onto the continental shelf.

'Train has left the station'

"The water that will upwell off the coast in future years already is
making its undersea trek toward us, with ever-increasing levels of
carbon dioxide and acidity," co-author Burke Hales, an associate
professor at Oregon State University, warned in a statement.

"The coastal ocean acidification train has left the station," Hales
added, "and there is not much we can do to derail it."

Hales also cited a strong correlation between recent low-oxygen events
off the Northwest coast and increasing acidification.

"The hypoxia is caused by persistent upwelling that produces an over-
abundance of phytoplankton," Hales said. "When the system works, the
upwelling winds subside for a day or two every couple of weeks in what
we call a 'relaxation event' that allows that buildup of decomposing
organic matter to be washed out to the deep ocean."

"But in recent years, especially in 2002 and 2006, there were few if
any of these relaxation breaks in the upwelling and the phytoplankton
blooms were enormous," Hales said. "When the material produced by
these blooms decomposes, it puts more CO2 into the system and
increases the acidification."

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