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Ocean acidification

Posted on 23 June 2010 by Ove Hoegh-Guldberg

While Andrew Bolt continues his character assassination, let's get back to the facts. There are several misconceptions about ocean acidification that require correction, both here and elsewhere.

1.     “Ocean acidification is not a problem because organisms show a variety of responses (both positive and negative).”

The fact that not all organisms or physiological processes respond in the same way to ocean acidification is well known (Hendriks et al. 2009).  This does not, however, logically lead to the conclusion that ocean acidification is not a problem. Organisms like reef building corals, for example, show a consistent 15-54% reduction in calcification with a doubling of atmospheric CO2.  This is a problem irrespective of whether some other groups ( e.g. some bivalves) don't show this type of response.  Given that corals build and maintain coral reefs, the impacts on this group of organisms alone are likely to be large and negative.  

2.     “Ocean pH varies greatly in time and space.  This variability is much greater than any potential effect of carbon dioxide.”

It is true that ocean pH and carbonate ion concentrations do vary over time and space.  The issue, however, here is whether or not average pH is changing over time.  This is essentially the same distracting argument that some people have about the weather (i.e. day-to-day variability in temperature - "it was cold today, therefore climate change is happening.") and climate change (i.e. long-term trends in average temperature). 

3.     “Organisms like corals have been around for hundreds of millions of years, over which time atmospheric carbon dioxide has varied greatly. Therefore, we don't need to be concerned about ocean acidification.”

The fact that corals have survived as a group over long evolutionary time periods is irrelevant to whether or not current changes in ocean pH will impact their ability to build coral reefs. Having a long evolutionary history, gives little information about whether or not marine calcifiers like corals were rare or not at any particular time. Extinction has never been the issue here.  The issue is as follows:  If corals become rarer (and/or calcify less) due to ocean warming and acidification (e.g. (Bruno and Selig 2007; De'ath et al. 2009) then their ability to build and maintain coral reefs will be diminished. This in turn will decrease the ability of coral reefs to provide ecological services and support to over 500 million people worldwide. 

4.     “Carbon dioxide has been high in the past year coral reefs have continued to lay down calcium carbonate”.

This is not supported by the bulk of scientific studies.  Most of the evidence, reveals that marine calcifiers like corals did not form carbonate reef systems during periods of high CO2 in the past (Veron 2008 etc.).  There are big gaps in the depositions of carbonate during these periods.

5.     “We don't understand how the ocean works hence we do not have good evidence that ocean acidification is occurring.”

Modelling studies based on what are essentially simple geochemical processes have matched the observed decline in ocean pH.  Essentially, while we are there is still much to learn about how the ocean works, there are many empirical studies that show that ocean pH is changing rapidly. An excellent description of this work can be found in Doney et al. (2009).  Ocean acidification is occurring at rates which dwarf anything seen over the recent past.

Bruno, J. F. and Selig, E. R. 2007. Regional decline of coral cover in the indo-pacific: timing, extent, and subregional comparisons. PLoS ONE 2 (1):e711.

De'ath, G., Lough, J. M., and Fabricius, K. E. 2009. Declining Coral Calcification on the Great Barrier Reef. Science 323 (5910):116-119.

Doney, S., Fabry, V., Feely, R., and Kleypas, J. 2009. Ocean Acidification: The Other CO2 Problem. Annual Review of Marine Science 1:169-192.

Hendriks, I., Duarte, C., and Álvarez, M. 2009. Vulnerability of marine biodiversity to ocean acidification: A meta-analysis. Estuarine, Coastal and Shelf Science.

 Veron, J. 2008 Mass extinctions and ocean acidification: biological constraints on geological dilemmas. Coral Reefs 27:459-472.

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Comments 1 to 50 out of 67:

  1. Some places eschew the use of English in all its marvelous efficiency and prefer to use the term "reduction in how alkaline the solution is" when what is meant is "acidification." Could we please avoid having a pointless debate over semantics here w/regard to the commonly accepted term "acidification" used to denote a numerically reduced pH measurement?
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  2. Just like we dont need forest planted on every square centimeter on land we dont need coral reefs on every spot in the seas either. Tress are domesticated and grows in parks and there is no universal reason why coral reefs should not be domesticated and kept under control as well. The problem is corals reefs as tourist resorts may decline in popularity if it bleaches out. But I am sure we can compensate any dead bleached stuff with cheap chines made colorful animated plastic replacements. City people wont be able to tell the difference anyway. Beside we also got some pretty good robotic fishes coming up from Japan, in case the fish population dies off at the same time, which we can add to the seas to enchant the experience for paying customers. The benefit with robotic fishes are multiple; predictable and reliable displays, good resistance to off shore oil leaks and agricultural chemicals, no stinky dead fish afloat on the beaches. Less fish in the sea will also reduce the bird populations that makes irritating sounds, scares the kids and leaves excrement’s all over the places.
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  3. Actually, Batsvensson, your humor is lost on me. Anyway, I think the point of the post by Ove Hoegh-Guldberg was to bring into relief 5 standard argument tropes that are logically non-sense, yet have traction, and must be pointed out when they occur. In this case the author simply cited ample evidence to refute the arguments. The arguments refuted are vacuous, as well, in any topic. Here is my catalog of these arguments: (1) because x and y respond differently to the level of z, the level of z doesn't matter. (2) because x varies over y, a claim that x depends on z can be dismissed. (3) because x has existed in the past, when y varied, x will exist forever no matter how y varies. (4) because x happened in the past under circumstance y, it will always happen under circumstance y. (5) because we don't know x, we don't have evidence that y. Part of the modern charm of deniers of science is that they sometimes argue based on logic that would have been debunked monks in the 15th century
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  4. *debunked by monks in the 15th century*
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  5. 15th Century monks were pretty cluey - we owe the preservation of the classical corpus to their efforts including the great philosophers of ancient times. Copernicus was a 15th century cleric as was Christopher Clavius, the Jesuit astronomer (there's a lunar crater named in his honour). A tiny bit off topic but it's nice to reflect on the cultural roots of the western scientific tradition.
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  6. Sorry, Clavius was 16th century :-).
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  7. chriscanaris, staying briefly off topic, I would suggest that the original roots were Eastern, thanks to the preservation and transmission of that corpus by the Byzantine and Islamic empires. They, too, would have easily debunked the nonsense 'logic' coming from the so-called skeptics.
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  8. I'm surprised that Andrew Bolt is not quoted the latest Doney paper: The Growing Human Footprint on Coastal and Open-Ocean Biogeochemistry, Science, 18.06.2010 "Climate change, rising atmospheric carbon dioxide, excess nutrient inputs, and pollution in its many forms are fundamentally altering the chemistry of the ocean, often on a global scale and, in some cases, at rates greatly exceeding those in the historical and recent geological record. Major observed trends include a shift in the acid-base chemistry of seawater, reduced subsurface oxygen both in near-shore coastal water and in the open ocean, rising coastal nitrogen levels, and widespread increase in mercury and persistent organic pollutants." As these influences (good) separated? In the same issue of the Science, Kerr (Ocean Acidification Unprecedented, Unsettling) said: "By spewing carbon dioxide from smokestacks and tailpipes at a gigatons-per-year pace, humans are lowering the pH of the world ocean. [I agree ...]", but ... ... "It's less clear [...] how marine life will fare. With nothing in the geologic record as severe as the ongoing plunge in ocean pH, paleontologists can't say for sure HOW organisms that build carbonate shells or skeletons will react [...]. In the laboratory, corals always do poorly [!!!]. The lab responses of other organisms are mixed [...]. In the field, researchers see signs that coral growth does slow, oyster larvae suffer, and plankton with calcareous skeletons lose mass [...maybe it's the leverage effect only: "reduced subsurface oxygen both in near-shore coastal water and in the open ocean, rising coastal nitrogen levels, and widespread increase in mercury and persistent organic pollutants"?] ."
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  9. When I see the 'we do not know every detail of what impact it will have' argument on ocean acidification I always wonder if none of these people have ever owned a fish tank. Anyone who HAS spent much time around fish tanks knows that when you get a new fish and you are adding it to an existing tank you should leave the fish in the plastic bag for a while and slowly exchange water from the tank to the bag. The point of this exercise is to normalize the temperature and pH... because just transferring a fish from one environment to the other can kill it. Fish don't react well to changes in pH or temperature... especially fast changes. Yet here we're changing both world wide at an ever increasing pace. No, we don't know exactly what problems that is going to cause. But we know enough to be sure it isn't going to be good.
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  10. CBDunkerson wrote : "When I see the 'we do not know every detail of what impact it will have' argument on ocean acidification I always wonder if none of these people have ever owned a fish tank." It also makes me wonder how any of these so-called skeptics can get into an aeroplane, what with the lack of complete knowledge of flight, especially with regard to something like flow physics. They seem to be content with the lack of complete knowledge there (and the odd plane falling out of the sky now and again), but are very insistent on complete knowledge with regard to AGW, otherwise, obviously, it must all be discarded.
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  11. When I researched this topic for my blog post, The 800 lb. Gorilla in the Ocean, I was struck by how complicated the issue is with multiple feedback loops within the ecosystem. I was also suprised to find that the impact of ocean acidification on organisms is essentially a ten year old science. Given that, I was astonished (not really) that Willis over at WUWT could read one journal article that describes ocean acidification due to human emisisons of CO2, and with a wave of his hand, he could dismiss the last ten years of science.
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  12. I have a post called "The Effects of Ocean Acidification on the Barents Sea." http://legendofpineridge.blogspot.com/2010/06/effects-of-ocean-acidification-on.html
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  13. Throwing caution to the wind, for arguments sake let’s use the following numbers: annual SO2 emissions = 9 tgms or approx 10 million tons annual CO2 emission = 7,200 tgms or 8,000 million tons. Now let’s assume that when only natural sources of the two gases are considered, then acidity is not an issue because both cycles are deemed to be in equilibrium. Therefore the following discussion reflects anthropic sources for the two gases as it is those amounts that lead to increased acidity levels. Now we look at what percentage of the two gases are believed to end up in the ocean. CO2 = 50% (IPCC) SO2 = 85% (the sulphur cycle) http://www.libraryindex.com/pages/3406/Sulfur-Cycle.html Anthropic SO2 emissions for the most part are land based (international air travel and shipping are not included in any statistics), the locale of the sources are important as the prevailing winds tend to carry the emissions out over the oceans. This is true for Asia, India and North America and some sections of Europe/North Africa. The 8,000 million tons of CO2 therefore needs to be reduced by a factor of 50% to 4,000 million tons. We then need to consider how CO2 is trapped in water. The vast majority of it (85%) is held as a gas molecule surrounded by a water molecule and does not have any impact on the acidity of the water when held this way. The remaining 15% however forms carbonic acid over a long slow process. http://antoine.frostburg.edu/chem/senese/101/solutions/faq/dissolving-gases.shtml We therefore have to only consider 15% of the 4,000 million tons of CO2 when considering its impact on acidity. This number becomes 600 million tons. Now we are comparing the 600 million tons of CO2 which forms as carbonic acid in the ocean with 6.5 million tons of SO2 which ends up in the ocean. With Carbonic acid having a pH of 5.7 and Sulphuric acid having a pH of less than 1.0, we then have to take into account the relative acidities of the two solutions to really understand their true effect on ocean water. The pH scale is not linear but logarithmic meaning the comparison between two consecutive pH levels is a magnitude of ten and between two pH scales it is 100 and so on. The difference between carbonic acid with a pH of 5.7 and sulphuric acid having a pH of less than 1.0, the separation of the pH is about 5. Hence the acidity between the two acids is substantial. Even if we reduce the amount of SO2 that ends up in the ocean to 20%, the comparative acidity with carbonic acid in the ocean is substantially greater. On another note, emissions of international flights and shipping are not included in country or UN data due to the fact those categories do not require reporting. Hence given that the bunker oil used by ships is perhaps the most SO2 polluting fuel used today and those emissions – especially the sulphur, fall directly onto the ocean. Also, emissions during the 1960’s to the mid 1980’s had higher SO2 content than current emissions – the result of clean air acts and the installation of scrubbers in industrial chimneys. Hence the proportion of SO2 to CO2 from those years would likely have been higher than what is portrayed in this analysis. Given that what we see happening in the environment reflects what occurred some 20 to 40 years ago, I then pose the question to you: which gas, when emitted into the atmosphere and then dumped into the ocean will likely have the greatest impact on ocean acidity?
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  14. My take on the "scientists are uncertain" argument: The earth is tied to metaphorical railroad tracks, and instead of untying the ropes, people are arguing about the train schedule.
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  15. Geo Guy, what's the time required for sulphuric acid deposited on terrestrial surface and lacustrine environments to find its way to the oceans and does it arrive eventually as a compound in solution with a strongly acid pH? I can see what you're driving at but I wonder if you can assume rapid 1:1 transport of of the kind your rough calculation implies. H2S04 falling on land and in lacustrine settings is going to be at least partially neutralized and locked up-- imagine acid rain falling into a karst terraine, for instance.
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  16. Geo Guy, that H2SO4 has a greater impact on ocean acidification than CO2 is not equivalent to CO2 having no impact. What it does mean is we have to be concerned with both.
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  17. SO2 is not well mixed in the atmosphere and has low lifetime. It tends to be much more of a problem regionally, near the point of emissions (i.e. on land), than in the oceans. Emissions has been dropping steadly for decades while ocean acidification is still increasing. May we should ask John to add this as a skeptic argument.
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  18. GeoGuy - your chemistry is wrong. It's the ***pKa*** of carbonic and sulfuric acid that are around 6 and 1, respectively; not ***pH***.. As long the solution we're talking about putting them into (in this case the ocean) way above the pKa, each CO2 molecule produces 1 hydrogen ion (acid) and each SO2 molecule (assuming it winds up as H2SO4) produces 2 hydrogen ions. I.e., under the circumstances we're talking about, sulfuric acid is not orders of magnitude stronger at acidification than carbonic acid; they're about the same.
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  19. It would be ridiculous to say that any ecosystem is a perfectly stable environment. So what matters is how the proposed human induced changes fits into these variable environments. Willis Eschenbach mused about this on WUWT suggesting that any human induced change was well within the spatial, diurnal and short term changes that occur in the pH of seawater. In "Watts it like at a climate skeptic speakers event?" there was a lot of skepticism in the discussion about how 'laboratory' experiments on CO2 induced changes in crop growth (FACE experiments) could be interpreted in the real world. These ocean pH experiments seem highly analogous. Any doubt here? I don't think it's distracting to consider the natural variation in the envoronment, in fact ignoring it would be to ignore an importantaspect of the question. That fact that the movement may be in one direction doesn't really annul the far more important fact about the magnitude of the change. Let's assume the worst case scenario's of AGW are true and we've already gone too far. Maybe this would only leave geo-engineering as a solution to this problem. We already have several ideas about how to tackle acidification. We have 50, 100, 200 or more years to get these experiments right before implementing them. This is the worst case scenario.
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  20. Also GeoGuy - that bit about only 15% of CO2 contributing to acidification - that's wrong, too. As I said, every CO2 molecule dissolved in the ocean produces 1 hydrogen ion.
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  21. What are those ideas about maintaining average ocean pH values, HR?
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  22. I have a couple of friends in the bivalve aquaculture industry. They expect 10-20 years before this seriously affects their business, but they're worried now. The Alaska Department of Fish and Game is concerned about acidification causing loss of pteropods because those are a major food of pink salmon. Sorry, I don't have a schedule for how long they think it will be before it affects their catches.
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  23. Steve I noticed that Willis' WUWT review of observed ocean pH makes a joke, "“The reports of the ocean’s death have been greatly exaggerated.” A nice bit of misdirection; nobody has said the oceans will die and meanwhile Willis' remark suggests that all organisms living in the ocean will respond identically to changing conditions. Tease out the threads of research and it turns out that some creatures are highly tolerant of varying pH and some are not. Willis is not quite up to his usual snuff with his pH writeup, though his rhetoric is just as entertaining as always. Even though one section of his dismissal of pH as a problem depends on notable stratification and poor mixing as identified by the authors of the work he plunders for juicy bits, later he declares that because the ocean volume is so vast it's impossible for the amount of added C02 to significantly change pH. These rationales are both supposed to work simultaneously on a timescale of a handful of decades. What I find really fascinating about Willis is the punctuation mark he represents, the shift in emphasis he brings with his writing. Willis is in fact dragging a number of reluctant WUWT readers backward along the path of contrarian thinking and at the same time realigning their thinking. He's corrected some perceptual problems with attribution of increased C02 in the atmosphere and in this pH piece he is in fact conceding that we're going to add a large amount of C02 to the ocean and thus measurably change its pH value. Willis is positively progressive compared to Steven Goddard or some of the old school authors practicing at WUWT. However he's also quite gifted with writing and apparently is using his skills to build acceptance of AGW's legitimacy while simultaneously focusing on downplaying impacts. In sum his work looks like a concession and subsequent shift to adaptation, consolation and Panglossian thinking but of course Willis is just one author and presumably could be drummed out if he smashes the "Overton Window."
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  24. HumanityRules #18, I don't see the parallel you suggest between crop growth and ocean pH studies. The objection in the crop growth study was that they simulated the positive impacts of increased CO2, but not the (more significant) negative ones. Are you suggesting that there will be beneficial effects to the oceans from acidification which could outweigh the negative ones? If so, what are these benefits?
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  25. Doug_bostrom # 14 – while you raise some good points, I believe that given the location of many coal fired generators in the US (east coast) it is likely that much of the exhaust finds itself falling directly into the ocean. Estimates for a linger time vary from 2 to 5 days – certainly enough time for the westerly winds to transport the SO2 and associated pollution over the Atlantic. Similar situations exist in Asia. Another factor to consider, as I pointed out, is the exhaust from ships using bunker oil which falls over the ocean as well. The point I was trying to make is that sulphuric acid is so much stronger than carbonic acid that once you factor in all of the relevant parameters, in my view it is difficult to attribute increased acidification of the ocean strictly on increased CO2.
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  26. GaryB # 15 – I never implied we shouldn’t, however 100% of the focus has been on Anthropic CO2 which is incorrect – a factor that continues to be characteristic of the debate. In order to determine the real effect of CO2 on ocean acidity, we need to factor out all of the effects of alternative sources that contribute to a rise on ocean acidity.
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  27. VoxRat # 17 – I stand by my numbers: The following links indicate that the pH of sulphuric acid and carbonic acid are 0.7 and 5.65 respectively. The premise is also based on the concept that pH approximates the negative Log 10 of the molar concentration of dissolved hydrogen ions. http://home.clara.net/rod.beavon/sulphuric_acid.htm http://www.chem.usu.edu/~sbialkow/Classes/3600/Overheads/Carbonate/CO2.html
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  28. VoxRat # 19 – the operative word you use is “Dissolved”. Not all CO2 entering the ocean gets dissolved.. Here is a sketchy outline of the process. As with the O2, the CO2 must cross the surface of the liquid: CO2(g) CO2(aq) It's a little easier for the CO2 to do so than for oxygen, because the oxygen ends of the molecule have a partial negative charge are better able to hydrogen-bond to the water as a result. The CO2 rather slowly acquires a shell of water molecules. A fraction of these hydrated carbon dioxide molecules react with the water to produce carbonic acid (H2CO3): CO2(aq) + H2O H2CO3(aq)
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  29. Geo Guy #26 - Unfortunately, there's no such thing as "the pH of sulphuric acid and carbonic acid". As in the links you've provided, the pH is not only dependant on the strength of the acid (the pKa), but also on the concentration. The sulfuric acid pH example has a concentration of "0.1 mol dm3"... if there would be enough SO2 in the atmosphere to reach such levels, you and I wouldn't be typing this. ;)
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  30. Geo Guy I think what you're suggesting is that we can't reliably attribute pH changes to C02 because there's a possible confounding influence from anthropogenic H2S04. It's possible to attribute pH changes to a particular source without reference to others. For instance, as a simple example let's say you have a container of water and two containers of sulfuric acid. Adding each container (slowly, of course!) of acid will change the pH a certain amount independently of the other. The situation of C02 and oceans is more complicated, of course, because the transport mechanism of C02 into the ocean and the associated chemical circus is more intricate than simply pouring acid into water. To figure out how much pH change can be exerted by a particular source one has to resort to models whether the source is C02 or H2S04. Given that pH changes from H2S04 will be additive with changes from C02, it's not strictly necessary to isolate H2S04 contributions; improving confidence in attribution to C02 can be done by improving the models used to calculate those contributions, coupled of course with direct observations. For those of us (me, for instance) who need some reasonable amount of information on the topic here's a useful paper that describes in detail accessible to us how atmospheric C02 interacts with the ocean: Ocean acidification due to increasing atmospheric carbon dioxide (pdf, Royal Society, Raven et al, 2005). Digging down, here's a really terrific paper describing the development of a model and providing some rich detail (including a fairly comprehensive table of equilibrium reactions) on how these processes can be modeled: Studying ocean acidification with conservative, stable numerical schemes for nonequilibrium air-ocean exchange and ocean equilibrium chemistry (pdf, JGR, MZ Jacobson, 2005)
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  31. GeoGuy (#27) I stand by my numbers: The following links indicate that the pH of sulphuric acid and carbonic acid are 0.7 and 5.65 respectively. " Whatever those links say, your statement makes no sense. The pH of a solution of sulphuric acid can be anywhere from <1 to 7, ***depending on the concentration***. You ***seem*** to be thinking of pKa, not pH. But, as I explained, if the solution your putting the carbonic or sulfuric acid into (in this case the ocean) is at a pH substantially above either pKa, both carbonic and sulfuric acid are going to be contribute comparably to acidification. (They'll differ by a factor of 2, since sulfuric produces two hydrogen ions for every one produced by CO2. "The premise is also based on the concept that pH approximates the negative Log 10 of the molar concentration of dissolved hydrogen ions." I have a bachelor's degree in chemistry and a doctorate in biochemistry GeoGuy. I really don't need you to explain how pH works. Believe me. You're wrong on this.
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  32. GeoGuy (#27) – "the operative word you use is “Dissolved”. Not all CO2 entering the ocean gets dissolved." Actually it is, *by definition*. Unless it's entering a s macroscopic bubbles. "Here is a sketchy outline of the process... [clipped misguided elementary chemistry lesson]" You've described a chemical equilibrium: CO2(aq) + H2O <-> H2CO3 ... but you've neglected the fact that - *in the ocean* - there's a further reaction: H2CO3 + OH(-) <-> HCO3(-) + H2O. So as fast as those CO2's react to produce carbonic acid (H2CO3), they soak up one hydroxide ion (OH-). That's acidification - it has exactly the same effect on the pH as does one half the number of sulfuric acid molecules: H2SO4 + 2OH(-) <-> SO4(2-) + 2H2O
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  33. Well, one thing you should be aware of. Really high CO2 partial pressure levels in oceans come from below, not above. These are upwelling areas and life just loves it. It's like an oasis in desert. Limnol. Oceanogr., 55(1), 2010, 239–248 Ocean acidification hotspots: Spatiotemporal dynamics of the seawater CO2 system of eastern Pacific coral reefs Manzello, Derek P. "During upwelling in the Galápagos, mean pCO2 [...] at five different sites ranged from 53.1 to 73.5 Pa" (524-725 ppm) This water comes from the abyss, has seen surface a long time ago. The same for California Undercurrent. Upwelling water pCO2 is 800 ppm.
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  34. Berenyi Peter: "These are upwelling areas and life just loves it. It's like an oasis in desert." You need to bear in mind there are (at least) three separate things to consider here. (1) pCO2 (2) (some) "life just loves" upwellings because among the things being upwelled are a lot of potential nutrients. (3) What we're talking about here is ocean acidification. All other things being equal, increasing pCO2 will decrease the pH. But all other things are *not* equal in this local upwelling perturbation. Do you know what the pH was?
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  35. #34 VoxRat at 09:47 AM on 25 June, 2010 Do you know what the pH was? Yessir! Guess where upwelling occurs.
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  36. Compare it to distribution of Chlorophyll a concentration along the tropics. Notice huge deep blue desert in south Pacific with rather high pH. At higher latitudes it's a different story, as CO2 solubility increases with decreasing water temperature.
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  37. "... complicated ..." So let us focus on Australia, the Australian scientists, Australian coral reef ... "Coral reefs under rapid climate change and ocean acidification" Hoegh-Guldberg et al., 2007, "Repeated bleaching episodes in the same coral assemblages and the increasing scale and frequency of coral bleaching have been cited as evidence that corals have exhausted their genetic capacity to adapt to rising sea surface temperatures ." "Indeed, the effects of temperature and acidification on even the most basic vital rates in corals, such as growth, mortality, and fecundity, are LARGELY UNKNOWN, as are the physiological trade-offs among these traits." "Consequently, the sensitivity of population growth to climate-induced changes in vital rates remains almost COMPLETELY UNEXPLORED. In the absence of LONG-TERM [!] demographic studies to detect temporal trends in life history traits, predicting rates of adaptation, and whether they will be exceeded by rates of environmental change, is PURE SPECULATION." "The majority of coral generation times, however, are still long (decades) relative to the ACCELERATING PACE of climate change, throwing doubt on the scope of most coral species for RAPID adaptation ..." And here (again) back, "ab ovum": "Abrupt tropical climate change: Past and present"(Thompson et al., 2006). If the former (including even those fairly recent) changes were more violent than the present or similar (and a lot to suggest it), then this question: "It took millions of years for these organisms [calcifying marine organisms] and ecosystems to recover."; is not the slightest importance ... Kleypas et al (2006) : " It is certain that net production of CaCO3 will decrease in the future", "Determine the calcification response to elevated CO2 in . . ", " .. in many cases even the sign of the biochemical response, let alone the magnitude, is UNCERTAIN ". Lough and Barnes (1997) found that "the 20th century has witnessed the second highest period of above average calcification in the past 237 years." Currently, however: "The study shows that the biggest and most robust Porites corals on Australia's Great Barrier Reef have slowed their growth by more than 14 percent since the "tipping point" year of 1990." "The data suggest that this severe and sudden decline in calcification is unprecedented in at least 400 years," Lough: "It is cause for extreme concern that such changes are already evident, with the RELATIVELY MODEST CLIMATE CHANGES observed to date, in the world's best protected and managed coral reef ecosystem," ... however: "The causes of this sharp decline remain UNKNOWN, but our study suggests that the combination of increasing temperature stress and ocean acidification may be diminishing the ability of Great Barrier Reef corals to deposit calcium carbonate," "Dr Lough said there had been some concern that coral growth has been declining in recent times. "However, data from density bands place these results into a larger context. Density bands show that coral growth and calcification on the Great Barrier Reef vary considerably over time."" "Coral records show that there have been several major increases and decreases over the past several centuries." Generally conclusion: "THE CURRENT DECLINE APPEARS TO BE A RETURN TO MORE NORMAL GROWTH CONDITIONS FROM HIGH GROWTH RATES EARLIER THIS CENTURY". ... ??? (http://www.reef.crc.org.au/publications/explore/feat37.html)
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  38. 33.Berényi Péter at 08:51 AM on 25 June, 2010 From Manzello 2010: "These naturally high-CO2 reefs persist near the Ωarag distributional threshold for coral reefs and are thus expected to be the first and most affected by ocean acidification"
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  39. 4. “Carbon dioxide has been high in the past year coral reefs have continued to lay down calcium carbonate”. ... and at the present day (the current state of knowledge), the word: "NORMAL" should suffice for us, the rest is really "pure speculation" ...
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  40. The increase in atmospheric pCO2 in the past 20 years, compared with 1.5 - 1.6% CO2 (free and chemically bonded) in the SS ocean ... Temperature - indeed the variability of El Nino - La Nina, the 90s, it was extremely violent - it is probably the most important here (does not "simply" temperature but its change - up - down). Anthropogenic pressures: period of 90 - those - that period of putting into service a significant number of large cruise ships, whose favorite "tour" is GBR. Direct damage to the GBR are not the most important fact here. Species, ecosystems individual reefs - atolls, it is often endemic. "Mixing species" - from bacteria to starfish ("The 2003 LTMP surveys showed that 15% of the surveyed reefs had outbreaks of crown-of-thorns starfish. This is higher than the number of reefs affected in the 1988 series, which resulted in widespread declines in coral cover on reefs in the central Great Barrier Reef ..." ) - is a disaster for most ecosystems GBR ...
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  41. The Independent Environment Great Barrier Reef polluted by pesticides By Kathy Marks in Sydney Thursday, 22 February 2007 "they show sediment creating a hazy cloud in the water over the reef, blocking out sunlight and preventing photosynthesis, the process which keeps coral alive" "sediment run-off carried pesticides washed off farmland" Well, stop whining about CO2.
    • use pesticides that decompose into harmless stuff in several weeks
    • promote farming practices that limit soil erosion, the Right Thing to Do anyway
    That's it.
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  42. Berenyi Peter: RE: pH Great! So now if we can just get the entire ocean to upwell, we can stop worrying that CO2-induced acidification is going to a problem. Though you did seem to miss thiz bit (that I meant to quote but Peter Hogarth did): "These naturally high-CO2 reefs persist near the Ωarag distributional threshold for coral reefs and are thus expected to be the first and most affected by ocean acidification" RE: pesticides "That's it" Pesticides are identified as a problem, therefore CO2/acidification is not?
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  43. Just add by the “ship and tourists”: AIMS, 1997: “Firstly, the effects of the outbreaks have been confined largely to the central third of the Great Barrier Reef where the majority of tourist developments are located. Such effects may have severe ramifications for the local economy of Queensland and Australia in general.”, “In essence they revealed that the central third of the Great Barrier Reef (between Lizard Island and Townsville) had been affected by outbreaks within the previous 6 years. Within this region approximately 65% of all reefs surveyed were considered to have experienced a recent outbreak of starfish.” And where to from here is “the place” for “acid” - CO2?
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  44. Arkadiusz Semczyszak at 18:31 PM on 25 June, 2010 and Berényi Péter at 08:51 AM on 25 June, 2010 We’re getting off topic. Concentrating on the global issue, I think the overarching concerns on anthropogenic CO2 (specifically) and reduced alkalinity of the Oceans can be summarized in the following images. from here which shows gridded annual average air/sea carbon flux. The ocean is a net CO2 sink and is changing pH most rapidly in areas of highest uptake. From R. Feely, Pacific Marine Environmental Laboratory, NOAA, with atmospheric data from Pieter Tans and seawater data from David Karl. Adapted from Feely (2008) in Levinson and Lawrimore (eds), Bull. Am. Meteorol. Soc, 89(7): S58. See also Sabines testimony and paper on this topic and Fabry 2008 where effects on the ocean ecosystem are discussed, and lack of detailed knowledge and need for more work is acknowledged, but: “Nevertheless, sufficient information exists to state with certainty that deleterious impacts on some marine species are unavoidable, and that substantial alteration of marine ecosystems is likely over the next century”. I think this fairly reflects the view of most published ocean researchers in this field that I have read. The current extremely high rate of increase in atmospheric CO2 is not something encountered in non-catastrophic “normal” geological history, and the trend should give cause for concern. We are correct to look at other factors and details also, but we should not miss the bigger picture. Why (if correct) is the balance of species changing?
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  45. "acid" - it's of course acid?: "The Intergovernmental Panel on Climate Change's worst case scenario predicted that the pH of ocean waters could decrease to 7.85 by 2100."
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  46. ... and whether such reconstructions: http://ioc3.unesco.org/oanet/OAimages/TurleypH.gif - are reliable and in general possible?
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  47. Berényi Péter at 08:51 AM on 25 June, 2010 and Arkadiusz Semczyszak at 18:42 PM on 25 June, 2010 You guys are rather missing the point. VoxRat and Peter Hogarth have mentioned this but it's worth emphasising what the issues are. We can use the Manzello paper [*] that you (Peter) referred to as a guide: You (Peter) are doubly confusing (i) the nutrient content and (ii) [CO2] content (acidity) of cold upwelling waters in relation to (a) fishery productivity and (b) coral sustainability. These need to be seperated out properly: Upwelling cold waters have high [CO2] (and highish acidity), and high nutrient content. These (largely inorganic; e.g. nitrates and phosphates) nutrients are required for the photosynthetic plankton in the surface waters where sunlight penetrates. These phytoplankton use photosynthesis to convert [CO2] to biomass and this process is nutrient-limited. Therefore upwelling nutrient-rich cold waters promote phytoplankton growth and this stimulates bioproductivity higher up the food chain (lots of sardines to fish). The [CO2] levels and acidity of the waters are relatively unimportant for this except for those orgainsms that fix carbonate into their shells and skeletons. This is the problem in relation to acidification of the oceans. Corals are particularly sensitive to acidification, and not surprisingly the areas of upwelling of [CO2] rich waters is detrimental to coral growth. Manzello points this out specifically: He says (p. 245 of the paper Peter referred to):
    "Not surprisingly, reef development is scant in this highly marginal environment and ephemeral on geological timescales (Manzello 2009). Binding calcium carbonate cements do not precipitate[**] above trace levels in this low-Sigma(arag) environment and rates of bioerosion are the highest measured for any reef in the world (Manzello et al. 2008)."
    [*] Manzello, D. P. (2010) Ocean acidification hotspots: Spatiotemporal dynamics of the seawater CO2 system of eastern Pacific coral reefs Limnol. Oceanogr., 55, 239–248 [*] i.e. the calcium carbonate "cement" that physically consolidates coral reefs, can't precipitate (it redissolves) as increased acidification drives down the concentration of dissolved carbonate, shifting the equilibrium between [carbonate(aq) ---- carbonate(precip)] in the direction of carbonate(aq).
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  48. Arkadiusz: ? No, it's not "acid". It's acidification: a drop in pH.
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  49. #38 Peter Hogarth at 18:32 PM on 25 June, 2010 "These naturally high-CO2 reefs persist near the Ωarag distributional threshold for coral reefs and are thus expected to be the first and most affected by ocean acidification" And how do you plan to prevent upwelling? BTW, damage to Galápagos reefs occurred during super El Niño events. When upwelling is suppressed, ocean pH goes up, and corals are starved to death.
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  50. Berényi Péter at 21:07 PM on 25 June, 2010 Peter, you really need to read the Manzello paper whose abstract you linked to. The very fact that upwelling waters are [CO2] rich and thus relatively acidic means that coral reefs struggle in regions of upwelling. Manzello states this explicitly. In fact it's much of the point of his study, namely that as ocean acidification becomes widespread the degradative effects on coral reefs he observes in the eastern Pacific and around the Galapagos, will occur throughout the oceans. I just described this here with an excerpt from the Manzello paper
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