Acid oceans update
- Fw: [CCG]
---------- Forwarded Message ----------
QUOTE: "They're seeing that the shells of these organisms start to
dissolve even while
the organism is still living," said Sabine, an oceanographer with
NOAA's Seattle lab.
Research in Pacific shows ocean trouble
Acidity rises, oxygen drops, scientists find
Friday, March 31, 2006
By LISA STIFFLER
Research fresh off a boat that docked Thursday in Alaska reveals some
frightening changes taking place in the Pacific Ocean.
As humans are pumping out more carbon dioxide that is helping to warm
the planet, the ocean has been doing yeoman's work to lessen the
effects -- but it's taking a toll.
Scientists lower 36 bottles used for water sampling from the deck of
the Thomas G. Thompson while doing research near the equator.
Over time, the changes could have an impact that ripples through the
food chain, from microscopic plants that can't grow right to salmon
and whales unable to find enough to eat.
The Pacific is getting warmer and more acidic, while the amount of
oxygen and the building blocks for coral and some kinds of plankton
are decreasing, according to initial results from scientists with
National Oceanic and Atmospheric Administration's Pacific Marine
Environmental Laboratory, the University of Washington and elsewhere.
"There are big changes," said Christopher Sabine, chief scientist for
one leg of the research trip, which ultimately traveled from
Antarctica to Alaska.
Many of the most interesting results are tied to the ocean becoming
increasingly acidic because of its absorption of carbon dioxide.
"You don't have to believe in climate change to believe that this is
happening," said Joanie Kleypas, an oceanographer with the University
Corporation for Atmospheric Research, a non-profit organization based
in Boulder, Colo. "It's pretty much simple thermodynamics."
And it's alarming.
"Acidification is more frightening than a lot of the climate change
issues," Kleypas said. That's in part because the process is hard to
"It's a slow-moving ship, and we're all trying to row with
toothpicks," she said.
Carbon dioxide is a byproduct of burning fossil fuels such as oil and
gas. Over the past 200 years, the ocean has absorbed about half of
what's been released into the atmosphere.
Sabine and the other researchers found that in the past 15 years,
there's been a detectable decline in the ocean's pH, which is a
measure of acidity ranging from zero to 14, with zero being most
acidic (water is neutral, or pH 7, while seawater is about pH 8).
The pH of the saltwater has dropped 0.025 units since the early
1990s. The number seems unremarkable, but the pH scale is
exponential, so a one-unit drop is a 10-fold decrease. The new
measurement also puts the ocean on track for a dramatic decline by
the end of the century.
Plankton -- tiny plants and animals that live in the ocean -- are
among the creatures that could be harmed by the change. In addition
to the water becoming more acidic, the extra carbon dioxide reduces
the amount of chemical compounds used to construct coral and the
shells of plankton.
"That's a major issue," said John Guinotte, a marine scientist with
the Bellevue-based Marine Conservation Biology Institute who studies
deep sea corals.
"You're likely looking at serious effects through out the marine food
web across the board," he said.
The pole-spanning trip that ended Thursday is part of the Repeat
Hydrography project. The most recent trip was aboard the Thomas G.
Thompson, a UW-operated vessel, and lasted about three months.
Thirty-five scientists from about a dozen universities and government
The plan is to survey 19 routes crisscrossing all the world's oceans,
then repeat those trips every 10 years to detect trends in ocean
conditions. Ocean measurements were taken every 60 miles from the
surface to the bottom of the sea.
Researchers from California State University-San Marcos and the
University of South Florida towed nets behind the vessel to catch
plankton, which they then subjected to acidic conditions on par with
what might be experienced in the future.
"They're seeing that the shells of these organisms start to dissolve
even while the organism is still living," said Sabine, an
oceanographer with NOAA's Seattle lab.
Some of the creatures tested are little snails that are "a major food
source for salmon and whales and these larger things and they make a
shell that is very susceptible to a decrease in pH," he said.
Other experiments show that microscopic plants at the base of the
food chain that build protective plates out of calcium carbonate
don't grow properly in the acidic water.
"We don't expect to go out and find living organisms with dissolving
shells," Sabine said. "We expect to find perhaps a change in where
these organisms are thriving or perhaps fewer of them over time."
The ocean scientists expressed an urgency over reducing carbon
dioxide emissions as soon as possible.
"Anything we can do to slow that rate of change will slow the rate of
response in the oceans as well," said Kleypas. "It buys us some time."
TO LEARN MORE
� The national project: <http://ushydro.ucsd.edu>ushydro.ucsd.edu
� Local participants:
P-I reporter Lisa Stiffler can be reached at 206-448-8042 or
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