Atmospheric carbon dioxide build-up probably is making the ocean more acidic.
University of Chicago scientists have documented that the ocean is growing more acidic faster than previously thought. In addition, they have found that the increasing acidity correlates with increasing levels of atmospheric carbon dioxide, according to a paper published online by the Proceedings of the National Academy of Sciences on Nov. 24.
"Of the variables the study examined that are linked to changes in ocean acidity, only atmospheric carbon dioxide exhibited a corresponding steady change," said J. Timothy Wootton, the lead author of the study and Professor of Ecology and Evolution at the University of Chicago.
These scientists collected the most detailed dataset of ocean pH.
The increasingly acidic water harms certain sea animals and could reduce the ocean's ability to absorb carbon dioxide, the authors said. Scientists have long predicted that higher levels of atmospheric carbon dioxide would make the ocean more acidic. Nevertheless, empirical evidence of growing acidity has been limited.
The new study is based on 24,519 measurements of ocean pH spanning eight years, which represents the first detailed dataset on variations of coastal pH at a temperate latitude—where the world's most productive fisheries live.
"The acidity increased more than 10 times faster than had been predicted by climate change models and other studies," Wootton said. "This increase will have a severe impact on marine food webs and suggests that ocean acidification may be a more urgent issue than previously thought, at least in some areas of the ocean."
The temperature rise due to CO2 build-up seems avoidable with fairly cheap climate engineering. But I do not see how we can prevent the oceans from becoming too acidic as atmospheric CO2 increases. The ocean acidity problem seems to me the most compelling argument for cutting CO2 emissions from fossil fuels burning.
Within 50 to 100 years, there could be severe consequences for marine calcifying organisms, which build their external skeletal material out of calcium carbonate, the basic building block of limestone. Most threatened are cold-water calcifying organisms, including sea urchins, cold-water corals, coralline algae, and plankton known as pteropods—winged snails that swim through surface waters. These organisms provide essential food and habitat to others, so their demise could affect entire ocean ecosystems.
The loss of shelled creatures will remove food supplies for larger marine animals.
By Randall Parker at 2008 November 24 10:36 PM Trends PollutionThe loss of shelled creatures at the lower end of the food chain could have disastrous consequences for larger marine animals. North pacific salmon, mackerel, herring, cod and baleen whales all feed on pteropods or sea butterflies, one of the species under imminent threat.
Randall,
Plymouth Marine laboratory here in UK has also been working on acidification. One of the key points they make is about the speed at which CO2 concentrations are rising are way over what has been seen in previous episodes. There is more at their website
One lecture I went to on this suggested that Ocean life would effectively reduce down to Jellyfish and algal blooms if things go on unabated.
Didn't these shelled organisms evolve over millions of years which included many periods with much higher atmospheric CO2 levels than today or even 2x today?
Yes they did, DF. In fact the ability of the ocean to absorb CO2 safely is essentially limitless for all practical purposes.
If CO2 were to drop as low as these true believers want them to, half the world's biosphere would be starved for carbon. They have no historical perspective.
In reality, the measurement precision the UC labbers claim is most unlikely. The problem is not only sample quality but the limits of measurement. But it makes great alarmist press, and gets a lot of those bloggers hopping.
I would suggest that controlled experiments are in order. There are plenty of huge aquariums associated with theme parks and research institutions around the world that could boost the acidity via CO2 and see what happens.
The idea that shelled organisms will be greatly diminished by increased atmospheric CO2 seems unproved to me. But I am certainly open to research, and the cost of research, about it. Fertilizer and salt runoffs seem more important to me.
Has anyone heard of the White Cliffs of Dover?
Cretaceous chalks formed when global temperatures and atmospheric carbon dioxide concentration were higher than now. Indeed, global temperature was 5 to 6 deg.C higher than now and atmospheric carbon dioxide was 4 times higher than now
(see e.g. http://www.jstor.org/pss/57127).
But the calcerous skeletons of oceanic creatures from that time are so abundant that they now comprise many hills and mountains around the world.
So, I wonder why some people fear that slightly higher global temperatures and slightly higher atmospheric carbon dioxide concentration than now would hinder formation of such skeletons.
Just because conditions in the geologic past had more CO2 does not mean they had more acidity. Perhaps you should ask what's different this time around, such as a lack of time for weathering to produce sufficient cations to buffer the acidity from the CO2.
Who has the latest, greatest methodology for accurate pH measurements in seawater while underway? Trying to link this to some red tide monitoring in quasi real time.