Research in Pacific shows ocean trouble.

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SEATTLE POST-INTELLIGENCER

http://seattlepi.nwsource.com/local/265052_acid31.html

 

Research in Pacific shows ocean trouble Acidity rises, oxygen drops,

scientists find

Friday, March 31, 2006

By LISA STIFFLER

P-I REPORTER

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.

Christopher Sabine, NOAA 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 alter.

" 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 labs participated.

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: ushydro.ucsd.edu

 

 

Local participants: www.pmel.noaa.gov/co2/co2-home.html

 

 

P-I reporter Lisa Stiffler can be reached at 206-448-8042 or

lisastiffler.

? 1998-2006 Seattle Post-Intelligencer

 

 

 

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