New Study Finds Increasing Acidification of Pacific Ocean’s Continental Shelf

May 22, 2008

An international team of scientists surveying the waters of the continental shelf off the West Coast of North America has discovered for the first time high levels of acidified ocean water within 20 miles of the shoreline, raising concern for marine ecosystems from Canada to Mexico.

Researchers aboard the Wecoma, an Oregon State University research vessel, also discovered that this corrosive, acidified water that is being “upwelled” seasonally from the deeper ocean is probably 50 years old, suggesting that future ocean acidification levels will increase since atmospheric levels of carbon dioxide have increased rapidly over the past half century.

Results of the study were published this week in Science Express.

“When the upwelled water was last at the surface, it was exposed to an atmosphere with much lower CO2 (carbon dioxide) levels than today’s,” pointed out Burke Hales, an associate professor in the College of Oceanic and Atmospheric Sciences at Oregon State University and an author on the Science study. “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.

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

Scientists have become increasingly concerned about ocean acidification in recent years, as the world’s oceans absorb growing levels of carbon dioxide from the atmosphere. When that CO2 mixes into the ocean water, it forms carbonic acid that has a corrosive effect on aragonite – the calcium carbonate mineral that forms the shells of many marine creatures.

Certain species of phytoplankton and zooplankton, which are critical to the marine food web, may also be susceptible, the scientists point out, although other species of open-ocean phytoplankton have calcite shells that are not as sensitive.

“There is much research that needs to be done about the biological implications of ocean acidification,” Hales said. “We now have a fairly good idea of how the chemistry works.”

Increasing levels of carbon dioxide in the atmosphere are a product of the industrial revolution and consumption of fossil fuels. Fifty years ago, atmospheric CO2 levels were roughly 310 parts per million – the highest level to that point that the Earth has experienced in the last million years, according to analyses of gas trapped in ice cores and other research.

During the past 50 years, atmospheric CO2 levels have gradually increased to a level of about 380 parts per million.

These atmospheric CO2 levels form the beginning baseline for carbon levels in ocean water. As water moves away from the surface toward upwelling areas, respiration increases the CO2 and nutrient levels of the water. As that nutrient-rich water is upwelled, it triggers additional phytoplankton blooms that continue the process.

There is a strong correlation between recent hypoxia events off the Northwest coast and increasing acidification, Hales said.

“The hypoxia is caused by persistent upwelling that produces an over-abundance of phytoplankton,” Hales pointed out. “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 added. “When the material produced by these blooms decomposes, it puts more CO2 into the system and increases the acidification.”

The research team used OSU’s R/V Wecoma to sample water off the coast from British Columbia to Mexico. The researchers found that the 50-year-old upwelled water had CO2 levels of 900 to 1,000 parts per million, making it “right on the edge of solubility” for calcium carbonate-shelled aragonites, Hales said.

“If we’re right on the edge now based on a starting point of 310 parts per million,” Hales said, “we may have to assume that CO2 levels will gradually increase through the next half century as the water that originally was exposed to increasing levels of atmospheric carbon dioxide is cycled through the system. Whether those elevated levels of carbon dioxide tip the scale for aragonites remains to be seen.

“But if we somehow got our atmospheric CO2 level to immediately quit increasing,” Hales added, “we’d still have increasingly acidified ocean water to contend with over the next 50 years.”

Hales says it is too early to predict the biological response to increasing ocean acidification off North America’s West Coast. There already is a huge seasonal variation in the ocean acidity based on phytoplankton blooms, upwelling patterns, water movement and natural terrain. Upwelled water can be pushed all the way onto shore, he said, and barnacles, clams and other aragonites have likely already been exposed to corrosive waters for a period of time.

They may be adapting, he said, or they may already be suffering consequences that scientists have not yet determined.

“You can’t just splash some acid on a clamshell and replicate the range of conditions the Pacific Ocean presents,” Hales said. “This points out the need for cross-disciplinary research. Luckily, we have a fantastic laboratory right off the central Oregon coast that will allow us to look at the implications of ocean acidification.”

Source: Oregon State University

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CWFlink
3.6 / 5 (9) May 23, 2008
Is the CO2 rise due to human activity or CO2 rising from fissures on the sea bed? Note the increasing siesmic activity off the Oregon and Washington coast. Also note that the ocean floor is littered with calcium carbonate deposits. I believe heat from deep lava flows, etc, would release CO2 from these minerals.

But also note: China is adding enough coal-fired electric power plants each year to equal the total electrical output of England... a "new England" each year, with very little in the way of polution controls. My first thought on reading the headline was that surface water was being tested... and certainly there I would expect all the CO2 released in China would be making its way across the ocean to our west coast.

So many possibilites, so little reporting on which we can make decisions....
Teonanacatl
2.9 / 5 (7) May 23, 2008
And also note: the poles of Mars is melting, Jupiter's climate is changing, storms on Saturn are intensifying, brightness of Uranus is increasing snd little Pluto's heating....
plaasjaapie
2.6 / 5 (7) May 23, 2008
This gets so tedious. I am really beginning to loathe this sort of propaganda. Take a look at CO2 levels in the atmosphere over geological time and then try to square it with the phony "concern" that these clowns are emoting.

http://biocab.org...cale.jpg

KB6
4.2 / 5 (5) May 23, 2008
Global warming may or may not be real. If it is real, it may or may not be caused by humans. But either way, it is a good idea for the entire industrialized world to reduce its dependence on fossil fuels, especially oil, for long-term geopolitical and economic reasons entirely unrelated to the environment.
Or do we wish to kowtow to a handful of tyrants, religious zealots, greedy corporations and commodities speculators until every last bit of it runs out?
plaasjaapie
3.7 / 5 (3) May 23, 2008
What BS! For most of geological time there has been a LOT more carbon in the biosphere than there has been since the end of the Mesozoic. More carbon means more living things.

The only tyrants and religious zealots that I see in this are the maniacs that are pushing human caused global warming.
yor_on
not rated yet Oct 12, 2008
There are a lot of 'debunker's' here.
Wonder where they come from?

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