The world’s marine ecosystems risk being severely damaged by ocean acidification unless there are dramatic cuts in CO2 emissions, warn scientists.
The researchers warn that ocean acidification, which they refer to as “the other CO2 problem”, could make most regions of the ocean inhospitable to coral reefs by 2050, if atmospheric CO2 levels continue to increase.
This does indeed sound alarming, until you consider that corals became common in the oceans during the Ordovician Era – nearly 500 million years ago – when atmospheric CO2 levels were about 10X greater than they are today. (One might also note in the graph below that there was an ice age during the late Ordovician and early Silurian with CO2 levels 10X higher than current levels, and the correlation between CO2 and temperature is essentially nil throughout the Phanerozoic.)
Perhaps corals are not so tough as they used to be? In 1954, the US detonated the world’s largest nuclear weapon at Bikini Island in the South Pacific. The bomb was equivalent to 30 billion pounds of TNT, vapourised three islands, and raised water temperatures to 55,000 degrees. Yet half a century of rising CO2 later, the corals at Bikini are thriving. Another drop in pH of 0.075 will likely have less impact on the corals than a thermonuclear blast. The corals might even survive a rise in ocean temperatures of half a degree, since they flourished at times when the earth’s temperature was 10C higher than the present.
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Graeme Rodaughan (07:58:45) :
In this forum – I also raise my hand and second Alan Millar’s request.
Could some one please explain how warming oceans can absorb more CO2 such that they can become acidified, given that warming oceans have a well known property of outgassing CO2.
I look forward to a real attempt to address this question.
The absorption of CO2 depends on the Revelle factor of the sea water. The concentration of CO2 is independently increasing, under those circumstances outgassing of CO2 will only occur if the sea surface temperature increases sufficiently to result in a greater mixing layer CO2 concentration than would be in equilibrium with the atmosphere (Revelle factor). If that isn’t the case the ocean will continue to uptake more CO2 from the atmosphere.
I looked at the other two HOTS data sets, and they don’t have pH data. So far we have seen three pH time series – Monterey Bay, Aloha and Kahe, and they all show a trend towards increased pH (decreasing acidity) over the last 10-15 years.
Foinavon:
You say:
“Come on Richard. We all know that the marked sinusoidal variation in atmospheric CO2 that “piggy-backs” on the rising atmospheric CO2 trend, is dominated by the N. hemisphere seasonal plant growth/decay cycles. We surely don’t need to readdress such extraordinarily basic and well-characterised phenomena…”
Well, I am aware of another group who say, “We all know Father Christmas exists”.
Sorry, but the N. hemisphere variation cannot explain the seasonal variation at Mauna Loa except as being an oceanic release and sequestration of CO2 relatively local to Hawaii. If you fail to understand this then look at a map and check the literature to determine how long it takes for CO2 released from the land in the N. Hemisphere to reach Hawaii.
Please do this check for yourself because everything I tell you seems to flow off you like water from a duck.
Richard
After millions of years of evolving adaptive genes, is it possible that coral has the ability to adapt to changes of co2 in it’s environment?
foinavon:
That is an excellent explanation of how buffering works with the real world numbers. I think they fail to realized that there is ALREADY an “excess” of CO3(2-) in the ocean due to CaCO3 CO3(2-) + Ca(2+).
So while they pound the table that “OMG MORE CO2 IN H2O MEANS MORE H2CO3 MEANS MORE CO3(2-)” in a water only solution they are right.
But the ocean has high [CO3(2-)] from the tons of CaCO3 added to it. Think about it, the pH is ~8.1. Not HCO3(-1)
3. Le Chatelier’s principle states that if you add H(+) to a system, you’ll push the equilibria in a manner that depletes initial [CO3(-2)]
4. So the question is, what is more important to the higher [CO3(-2)] ALREADY in the ocean at pH 8.1, HCO3(-1) or H+?
5. [CO3(-2)] is already present in the ocean probably from all the CaCO3 added to it.
Alan Wilkinson review your PhD.
I’m off to work on mine.
Richard S Courtney (10:11:52)
Not really Richard. Go to the Mauna Loa observatory site, look at the Mauna Loa data, and scroll down to the Global Monthly Mean data (averaged over all the ocean surface sites). You’ll see that they’re rather similar. On the mothly/seasonal timescale the equilibration of CO2 across the globe is reasonably efficient. Clearly the Mauna Loa data is not measuring a “relatively local” effect.
Here’s the data:
http://www.esrl.noaa.gov/gmd/ccgg/trends/
Directly comparing the qualities of modern corals to the Paleazoic corals in this context is laughable and plainly ridiculous. You do undertand the basic process of evolution do you? You do understand that a lot of changes happen to organisms over geological time (in this case over 400,000,000 years)?
We need to know, do you really understand evolution?
“the seasonal variation at Mauna Loa except as being an oceanic release and sequestration of CO2 relatively local to Hawaii.”
Makes sense to me.
What you describe as “abrupt changes” in CO2 over the last 100 years are in fact less than 3% of the difference between Ordovician and modern concentrations.
For the third time corals species that were extant in the Ordovician are (a) calcite-forming and (b) now extinct anyway, so I don’t really see where you’re going with the comparison. But let’s follow this through … you are equating a change in CO2 concentrations from 6000 to 385ppm over 460,000,000 years [assuming your figures are correct] with a rise of circa 100ppm over 100 years? Do you really expect corals to adapt in a few generations to such a historically steep rise.
Others have now pointed out where to find the evidence of falling ocean pH, I could have added that there were copious references in the Royal Society report on Ocean Acidification (damn, there it is again, In fact the term even has its own domain name and an NOAA web page) I linked to above.
No answer to my request for a marine biologist who agrees with your ‘no big deal’ stance yet. OTOH, Ove Hoegh-Guldberg has over 100 publications in this area and you can read his blog here.
Wow html WRECKED my last post.
E.M.Smith:
Actually, there are [H+] ions (or H3O+ if you like), in solution at pH greater than 7. They don’t ALL react with OH- at pH above 7. All pH above 7 means is that OH- molecules outnumbers H+ ions in solution.
Water has a dissociation constant of 10^(-14) [which is why a pH scale generally ranges from 0-14. Water spontaneous dissociates H2O -> H+ & OH-.
foinavon:
That is an excellent explanation of how buffering works with the real world numbers. I think they fail to realized that there is ALREADY an “excess” of CO3(2-) in the ocean due to CaCO3 == CO3(2-) + Ca(2+).
So while they pound the table that “OMG MORE CO2 IN H2O MEANS MORE H2CO3 MEANS MORE CO3(2-)” in a water only solution they are right.
But the ocean has high [CO3(2-)] from the tons of CaCO3 added to it. Think about it, the pH is ~8.1.
Wilkinson, you said:
J Lo, if you add some other acid (not CO2) to the ocean, yes, you will reduce carbonate ion levels. But if you add CO2 you won’t because you are adding carbonate ion with the acid.
1. CO2 adds H+ to the ocean
2. H(+) & CO3(-2) -> HCO3(-1),
3. [CO3(-2)] is already present in the ocean, probably from all the CaCO3 == Ca(2+) & CO3 (2-)
4. Le Chatelier’s principle states that if you add H(+) to a system, you’ll push the equilibria in a manner that depletes initial [CO3(-2)].
5. So the question is, what is more important to the higher [CO3(-2)] ALREADY in the ocean at pH 8.1 starting, dissociation of HCO3(-1) or the addition of H+?
Alan Wilkinson review your PhD.
I’m off to work on mine.
pkatt (02:34:40) : Can I say EEEK? Anyone wanna know what happens to corals when you get a plankton bloom??
http://www.int-res.com/articles/meps/60/m060p299.pdf
so I guess its ok to destroy it to save it huh?
Sigh. And we had the link upthread about NO3 causing coral death due to their nitrate sensitivity. So let me get this straight… We’re going to dump a load of nitrogen fertilizer into the ocean to save the coral from the evil CO2? And we’re adding iron to stimulate the growth of plankton as though the bloom is not going to be a problem? OK…
Well, look on the good side, it’s only about 3 Buicks worth of iron…
Hopefully they learn something other than how to create a bloom. (We already know how to do that…)
You know, I have to wonder what the bottom dwelling organisms will think about all this food rich planktonic rain falling on them. Gotta be good, right? It’s not like we don’t know much about the deep oceans. Heck, we’ve been to the moon, we must know more about the ocean bottom. /sarcoff>
@ur momisugly Steven Goddard,
“Chris J,
I plugged the first two HOTS pH data sets into a spreadsheet (Kahe and Aloha) and both showed a positive trend in pH over their length of record. I will look at the other two records later.
http://spreadsheets.google.com/pub?key=pj0h2MODqj3i9dc6DdtQDPw
http://spreadsheets.google.com/pub?key=pj0h2MODqj3h1BPd_ggZfSQ
You make bold claims that the data supports your contention of increased acidity, when in fact it does not.”
I don’t know what you’re doing wrong, but there issomething seriously wrong with your data query. The data you present above are not the data you think you have.
You can see the pH time series here (select pH comparison):
http://hahana.soest.hawaii.edu/hot/trends/trends.html
pH was assessed using both spectophotometric methods with m-cresol purple (= ‘measured’) and in accordance with equilibria given measured values of TCO2 and TA (= ‘calculated’).
As you can clearly see, pH is taking a nose dive. The BATS data show the same trend, as do other data sets.
How you ever got it in your head that oceanic pH is rising, or that these data sets show an increase in pH is beyond my comprehension. It requires nothing more complicated than looking at the time-series…perhaps that’s too much to ask. I forget who it was that said it, but it rings ever true: you are entitled to your own opinion, but you are not entitled to your own facts.
You say my claims are bold: no sir, far from it. I am simply familiar with this issue and with the pertinent data, while you clearly do not have even a rudimentary understanding of the chemistry or the available data. As you can see very clearly oceanic pH is dropping, precisely as I said, and opposite your claims to the contrary.
Chris
J Lo:
I think they fail to realized that there is ALREADY an “excess” of CO3(2-) in the ocean due to CaCO3 CO3(2-) + Ca(2+).
J Lo, “they” – the equations involved – don’t “fail to realize” anything. And I would assume that your obsession with anthropocentrizing inorganic chemistry also extends to your whole thought process.
John Philip,
The NOAA web page shows a graph with decreasing pH from HOTS over the last 20 years. However, if you go to the HOTS web site and extract the data for yourself (as I did and linked above and below) there is no such trend.
http://hahana.soest.hawaii.edu/hot/hot-dogs/bextraction.html
http://spreadsheets.google.com/pub?key=pj0h2MODqj3i9dc6DdtQDPw
That is why I asked for raw data.
Mary Hinge,
Your rude post really isn’t worth responded to, but if you believe that the chemical properties of CaCO3 have changed since the Ordovician, please share that theory with us.
JamesG (04:18:42) : To me the Cuba conundrum eliminates CO2 as a stress on coral because it is pristine while surrounded by Caribbean coral which is highly “stressed”. You don’t need to be a chemist or biologist to reach that conclusion but anyway, marine biologists say this pristine Cuban coral is due to other human factors and not due to a lack of acidification. If there is actually a particularly alkaline sea found around Cuba then again please point this out to me
Fascinating …
Hmmm. What’s different about Cuba?
1) Embargo.
2) No herds of beached northern white whales on vacation (I are one…)
3) Generally brown / dark skins.
4) Less intensive agriculture.
So I see 2 possible things to investigate (plus whatever I didn’t see 😉
1) It’s the sunscreen (as mentioned upthread).
2) It’s the ag runoff (or lack thereof).
I tend to doubt #2 just from a bias that they might not have the best sewage systems, but that’s a preconceived bias on my part. Any statistics on sunscreen sales in Cuba?
Are there any other tropical paradise settings with pristine coral not being flooded with sunscreen laden tourists? It would make an interesting thing to map…
Just to clear some of the FUD from the water, the chemical composition of aragonite and calcite (CaCO3) is identical, and there are many forms of shellfish in the oceans now that are quite similar to ones that lived in the Ordovician.
And yes we all know that there are lots of scientists who are worried about CO2. That is the point of examining the unfiltered data directly in these articles, to see if their underlying assumptions are correct.
Graeme Rodaughan (07:53:57) :
With luck and much hard work chasing funding, you may become as wise as the wisest climate scientist and be able to fathom such mysterious ambiguities.
Ahhh… Enlightenment is coming to me now…
I propose that we skeptics form the “CO2 is Evil Working Group to Save the Corals” and that we get a grant to study the pristine corals response to sunscreen when in an enhanced CO2 regime. This will involve jetting off to pristine tropical locations, slathering on lots of sunscreen, sucking down as much carbonated beverages as we can hold, then swimming out to examine the Corals. Repeatedly. We will also need a specific area set aside for the ‘nitrogen enrichment’ control group that results some time after large amounts of carbonation …
No one has taken my 6 Sigma offer. OK, price reduction.
4 Sigma.
RE: Moving seamlessly from aragonite to calcite skeletons with pH ~7.7.
I forget the organism but I remember reading, in the last year, of this as accomplished fact. Before you lash back, I’m an aquarist and have a Bio major focussed on evolution(yeah, I’m pro).
“Alan Wilkinson review your PhD.”
Hold up a sec.
The crustal abudance of both Ca and Mg are an order of magnitude greater than C. In the ocean at low pressure and high temperatures CO2 precipitates out of solution in combination with either metal.
In the high pressures of the abyss, CO2 re-enters solution. There are 50,000 Gtons of dissolved CO2 in the oceans, perhaps twice that in precipitates.
Some of the postings on this blog start with the false premise that the oceans are releasing more CO2 than they take up and this process is sometimes referred to as “out gassing.” What is the basis for this idea? It is completely false.
Every basic text book on the environment notes that the oceans are the major sink for the earth’s C02. This means, on a net basic, that much carbon is absorbed into the oceans and is eventually deposited on the bottom. This is not just about inorganic carbon chemistry. Most of the carbon that ends up on the bottom of the ocean enters food chains through algal photosynthesis. This is why some people are talking about fertilizing the southern oceans with iron (Fe) to increase the uptake of CO2 by the oceans. My readings on this suggest that even a massive effort would not work, because much of the organic carbon will decompose before it gets deep enough and exchange of surface and deep water is too slow. Some of the carbon that sinks to bottom is in the form of calcareous protists, such as the ones forming the “Cliffs of Dover.” However, my understanding is that most of the sedimenting carbon was fixed by photosynthetic algae (if anyone can come up with data on the relative contributions of these sources (calcareous heterotrophs vs phytoplankton), I would like to see the data.
Please give up on the notion that the oceans are releasing more CO2 than they take up. The number posted above by foinavan says that the oceans are helping us by removing 40% of human-released carbon dioxide. I don’t have the numbers on my fingertips, but this seems about right. This is a massive amount of carbon moving from the atmosphere to the ocean sediment. This makes the increase in atmospheric CO2 slower than it would have been without this sink.
There has been some discussion of how pH changes with depth. This also has a biological explanation, rather than an explanation in inorganic chemistry. Photosynthesis exceeds respiration in well lit surface waters, leading to slightly more basic pH in the upper layers. (remember that photosynthesis takes up CO2 and this reduces acidity). As you go deeper in the water column of a (deep) lake or an ocean, there is not enough light for photosynthesis, so respiration of algae, bacteria and animals leads to a net release of CO2 and a lowering of pH. Corals are fairly shallow, so they response to near surface pH, temperature and light. Any number of lab experiments show that corals are negatively impacted by increases in temperature, decreases in pH and high levels of UV light. Corals require light for their symbiotic algae, but too much light, especially in the ultra violet wave lengths, is destructive.
So tell me now, just how much CO2 is bubbling up from the floors of the oceans? When a submarine volcano forms a new island does the ph in the surround waters change and how much?
Does this CO2 bubbling up from the floors of the oceans dissolve into the ocean water more readily than does CO2 from the atmosphere? If I have some time I will check these things out. But blaming an “man’s CO2 emissions for a lowering ocean ph when there are many, many things we don’t know about the oceans seems questionable.
A surface ocean Ph of 8.179 or 8.104 seems to be as much of a fiction number as the annual global mean temperature.
“” Richard S Courtney (10:11:52) :
Foinavon:
You say:
“Come on Richard. We all know that the marked sinusoidal variation in atmospheric CO2 that “piggy-backs” on the rising atmospheric CO2 trend, is dominated by the N. hemisphere seasonal plant growth/decay cycles. We surely don’t need to readdress such extraordinarily basic and well-characterised phenomena…”
Well, I am aware of another group who say, “We all know Father Christmas exists”.
Sorry, but the N. hemisphere variation cannot explain the seasonal variation at Mauna Loa except as being an oceanic release and sequestration of CO2 relatively local to Hawaii. If you fail to understand this then look at a map and check the literature to determine how long it takes for CO2 released from the land in the N. Hemisphere to reach Hawaii.
Please do this check for yourself because everything I tell you seems to flow off you like water from a duck.
Richard “”
I must be getting senile; I downloaded the NOAA graph of the Mauna Loa Data, so I could see the “marked sinusoidal variation” that Foinavon mentioned; and I can’t find hide nor hair of a sinusoidal variation.
I do see about a 6 ppm peak to peak sawtooth looking variation which has an upside taking 8 months of the year, and a downside for the next 4 months, with very sharp turnaround at the extrema; but I maybe don’t have enough resolution to see the sinusoid he mentioned.
If I had to bet, I would say that the sawtooth is actually the exponential decay of an integrated rectangular waveform, with a 2:1 duty cycle. With a 6ppm drop in four months, that starting rate would eliminate 100 ppm in about 5 1/2 years. But assuming it is an exponential decay of the form:-
1-e^-(t/T), then it would take three time constants to eliminate 95% of the excess, or 99% in five time constants; and the time constant is that 5.5 year number.
So 95% could be removed in 16.5 years by whatever process is causing the ML saw tooth. At the North pole the amplitude of the saw tooth is 18 ppm, so it only takes 5.5 years at that location.
But tell me more about the sinusoidal component ?
foinavon:
What happens to the protons? They mostly protonate carbonate because carbonate has a higher affinity for protons than bicarbonate.
“Mostly”, really?
foinavon, your reasoning is obviously circular/wishful* and qualitative, not quantitative. Adding CO2 on the left must increase CO3 on the right, of course, along with increased H, as per usual. “Chemical intuition” has nothing to do with it. From a chemical bonding perspective, H doesn’t “like” CO3 any more than it used to. There are indeed more H’s, but there are also more CO3’s, and in the exact same proportions as there were before.
Again, there is more CO3!
So there is no new distorting perturbation from adding CO2 which magically causes CO3 to disappear at a net rate greater than it did before, as compared to the reactions which form it, and which are producing more CO3: the ratio of CO3/HCO3 is the same, but there is indeed more CO3.
*It appears that you are now using the increased H twice, once to do what it does as a result of the basic inorganic chemistry involved, then once more to form an excess of HCO3 beyond the basic chemistry, almost as if it “decided” to do it because you want it to. That doesn’t work.
Otherwise, foinavon, simply write the equations which actually show a net loss of CO3 resulting from the addition of CO2.
I guess it wouldn’t suit their purposes to describe the process of changing the pH from 8.179 to 8.104 as a neutralization of the ocean’s pH which is accurate as opposed to acidification which is inaccurate