These findings, plus a companion paper on the impacts of anthropogenic CO2 on the chemistry of the oceans and the potential response of certain marine species to the changes in CO2 levels, will be published in the July 16 issue of the journal Science. Lead authors for both papers are scientists with NOAA.
Sabine and his colleagues from the United States, South Korea, Australia, Canada, Japan, Spain, and Germany reviewed data gathered during the 1990s as part of three major research programs: the World Ocean Circulation Experiment (WOCE), the Joint Global Ocean Flux Study (JGOFS) and NOAA’s Ocean-Atmosphere Carbon Exchange Study (OACES).
This new global data set of ocean-carbon system observations, co-sponsored in the United States by NOAA, National Science Foundation and Department of Energy, is unprecedented with more than 72,000 carbon measurements, 10 times more observations than the previous global survey in the 1970s and 10 times more accurate.
“This research presents the first complete synthesis of modern global ocean inorganic carbon measurements,” said James Yoder, director of NSF’s ocean sciences division.
There are two large reservoirs of carbon that are capable of taking significant amounts of CO2 out of the atmosphere: the ocean and land plants. Studies over the last decade have indicated that the land plants are taking up CO2 at rates comparable to the oceans. The new high quality ocean carbon measurements allow scientists to determine that over a 200-year time-scale, the land plants have released more CO2 to the atmosphere than they have taken up. Over the long-term, therefore, the ocean has been the only reservoir to consistently take up anthropogenic CO2 from the atmosphere.
The uptake of anthropogenic CO2 by the ocean changes its chemistry and potentially can have significant impacts on the biological systems in the upper oceans.
Richard Feely, a marine chemist with the NOAA Pacific Marine Environmental Laboratory, and colleagues describe two major impacts of the oceanic uptake of anthropogenic CO2. First, they demonstrated that a substantial amount of the calcium carbonate shells produced in surface waters dissolves in the upper ocean. Second, they summarized the available evidence on the response of marine calcifying organisms to elevated CO2.
Feely noted that scientists have seen a reduced ability to produce protective calcium carbonate shells in many species of marine organisms at high CO2 levels, including corals and free-swimming algae (plant-like organisms) and animals on which other marine life feed. Recent studies have shown that calcification rates can drop by as much as 25 percent to 45 percent at CO2 levels equivalent to atmospheric concentrations of 700 to 800 parts per million that will be reached by the end of the century if fossil fuel consumption continues at projected levels.
The scientists note that the dissolving calcium carbonate shells also partially act to neutralize the CO2, thus allowing the ocean to take up more carbon dioxide from the atmosphere. However, the effects of decreased calcification in microscopic algae and animals could alter marine food webs and, combined with other changes in salinity, temperature and upwelled nutrients, could substantially alter the diversity and productivity of the ocean.
NOAA is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and providing environmental stewardship of the nation’s coastal and marine resources. NOAA is part of the U.S. Department of Commerce.
Fizzy water is a sign of CO2 over-saturation, usually resulting from warming the water or decreasing the CO2 partial pressure. Seawater is under-saturated, hence its ability to continually absorb CO2, and thus is not fizzy. The soda comparison is a silly introduction to a serious subject.
It’s a mnemonic. Some kid reading this very story on SciScoop will remember the image of a soda pop planet, get interested in global warming where they otherwise wouldn’t have even read the boring article, and grow up to save the world because I had a silly intro for a deadly serious subject. Not bad for a day’s posting.
Besides, how else is anybody gonna learn about Brix cups, one of the great inventions of the early 20th Century?
Most of the DIC is not in the form of CO2; 97% of it is in the form of HCO3 bicarbonate ions. The point is that adding 2.5% more CO2 is having a leveraged effect on the HCO3 ions in the oceans, modifying their normal equilibrium and making the oceans noticably more acidic. Saying anthromorphic CO2 is “only” 2.5% of the ocean carbon like saying beer is “only” 4% alcohol. You can still easily tell the effect of it on your body compared to drinking pure water.
And it’s 118 billion metric tons…
A little something was left out from that scary report, which mentions that oceans have absorbed 118 metric tons of anthropogenic carbon dioxide. But a related study by one of the authors said that’s about half the amount of variation during the seasons. The relative concentrations are 2000 to 50, or 40 to 1, or 2.5%. Seasonal variation is about 100, or 5%. Just as in the atmosphere, the large amount of natural carbon made detection difficult.
Direct Estimates of the Oceanic Inventory of Anthropogenic Carbon
Scott C. Doney and Christopher L. Sabine
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…my own soda fountain, but they’re too expensive for how little I drink now. Maybe if I had a big extended family living with me it would be cost effective.
It’s an interesting article, but something that the activist environmentalists might use to decry the mysteriously inconclusive global warming. Strange, but I just read somewhere that in the past 100 years the sun has gotten slighter hotter — meaning it (more than the industrialized nations) is warming the Earth.
The interesting conclusion of the article — that “the effects of decreased calcification in microscopic algae and animals could alter marine food webs and, combined with other changes in salinity, temperature and upwelled nutrients, could substantially alter the diversity and productivity of the ocean” — is expressed in non-definitive terms. In other words, this study doesn’t know exactlty what might be happening or what might happen to the ocean’s flora and fauna.
jon
“Just as in the atmosphere, the large amount of natural carbon made detection difficult. “
The proportion of man-made to natural CO2 in the atmosphere is ~50%. The increase in CO2 is easily measurable, partially because the atmosphere is so well mixed. in fact, a graph of data available since 1958 shows a small annual oscillation superimposed on a dramatic linear increase.
Just because I can :-)
Basically, the ocean is a giant acid-base buffer. It’s many other things as well, but since we’re talking about CO2, the buffer is what’s relevant.
For those who have forgotten their high-school chemistry, buffers have some very strange properties, in particular their ability to absorb large amounts of acid (or base) with minimal change in pH – up to a point. Once that point is reached, a small addition of acid (or base) “blows the buffer” and a dramatic change in pH happens. To graph it, it looks something like this: (let’s see how my ASCII art turns out…)
|
|
|
| \
p | \
H | \
| `---------,
| \
| \
|
+---------------------------
add acid --->
(digression: this whole acid-base buffer thing is why we can eat tomatoes without dying from a messed-up pH)
Exactly how “long” that flat part is depends on a lot of factors, including how much buffer is dissolved in solution.
The buffer in the case of CO2 in the oceans is actually a multiple buffer:
C02 + H2O <–> HCO3– + H+
HCO3– <–> CO32- + H+
Which means as you add more CO2, the first reaction’s equilibrium shifts a bit to the right and more HCO3– is produced, which shifts the second reaction’s equilibrium a bit to the right and more CO32- is produced.
However, as mentioned at the end of the article, this isn’t the end of the story. Some marine life uses calcium carbonate (CaCO3) in its shell. (Recognize that carbonate ion?)
As both of the above equations shift right, more acid (H+) is produced. CaCO3 dissolves in acidic solution, and neutralizes the acid via the exact reverse of the second equation above. So in a sense, it’s a triple buffer, if you don’t mind killing marine animals whose lives depend on those CaCO3 shells.
Also, despite all the buffering, the level of CO2 dissolved in the ocean does increase, and excess dissolved CO2 causes dissolved-oxygen-breathing fish distress much as it causes us free-oxygen-breathing critters distress when the free CO2 level rises.
Because the ocean is such a huge buffer, it’s taken a long time before we’ve noticed the effects of all the CO2 we’ve been pumping out. I hope we can smarten up and stop expecting the world to clean up after us, because it’s only got so much capacity…
Saying anthromorphic CO2 is “only” 2.5% of the ocean carbon like saying beer is “only” 4% alcohol. You can still easily tell the effect of it on your body compared to drinking pure water.
Actually, saying anthromorphic CO2 is “only” 2.5% of the ocean carbon is like saying one beverage is 97.5% alcohol and another is 100% alcohol. You can’t easily tell the difference in effect between them when compared to drinking pure water.
Grab a bushel of oranges and try the math for the “long term potential”.
Apparently we’re dangerously deficient in carbon dioxide:
“In the last 600 million years of Earth’s history only the Carboniferous Period and our present age, the Quaternary Period, have witnessed CO2 levels less than 400 ppm.”
How did ocean life survive past levels of carbon dioxide?