In the past, I have responded to questions at talks I have given on ocean acidification with an “I don’t know.” I hadn’t studied the theory and didn’t want to knee-jerk respond with skepticism just because the theory came from people who propounded a number of other theories I knew to be BS.
The theory is that increased atmospheric CO2 will result in increasing amounts of CO2 being dissolved . That CO2 when in solution with water forms carbonic acid. And that acidic water can dissolve the shells of shellfish. They have tested this by dumping acid in sea water and doing so has had a negative effect on shellfish.
This is one of those logic chains that seems logical on its face, and is certainly scientific enough sounding to fool the typical journalist or concerned Hollywood star. But the chemistry just doesn’t work this way. This is the simplest explanation I have found, but I will take a shot at summarizing the key problem.
It is helpful to work backwards through this proposition. First, what is it about acidic water — actually not acidic, but “more neutral” water, since sea water is alkaline — that causes harm to the shells of sea critters? H+ ions in solution from the acid combine with calcium carbonate in the shells, removing mass from the shell and “dissolving” the shall. When we say an acid “eats” or “etches” something, a similar reaction is occurring between H+ ion and the item being “dissolved”.
So pouring a beaker of acid into a bucket of sea water increases the free H+ ions and hurts the shells. And if you do exactly that – put acid in seawater in an experiment – I am sure you would get exactly that result.
Now, you may be expecting me to argue that there is a lot of sea water and the net effect of trace CO2 in the atmosphere would not affect the pH much, especially since seawater starts pretty alkaline. And I probably could argue this, but there is a better argument and I am embarrassed that I never saw it before.
Here is the key: When CO2 dissolves in water, we are NOT adding acid to the water. The analog of pouring acid into the water is a false one. What we are doing is adding CO2 to the water, which combines with water molecules to form carbonic acid. This is not the same as adding acid to the water, because the H+ ions we are worried about are already there in the water. We are not adding any more. In fact, one can argue that increasing the CO2 in the water “soaks up” H+ ions into carbonic acid and by doing so shifts the balance so that in fact less calcium carbonate will be removed from shells. As a result, as the link above cites,
As a matter of fact, calcium carbonate dissolves in alkaline seawater (pH 8.2) 15 times faster than in pure water (pH 7.0), so it is silly, meaningless nonsense to focus on pH.
Unsurprisingly, for those familiar with climate, the chemistry of sea water is really complex and it is not entirely accurate to isolate these chemistries absent other effects, but the net finding is that CO2 induced thinning of sea shells seems to be based on a silly view of chemistry.
Am I missing something? I am new to this area of the CO2 question, and would welcome feedback.
In a blog filled with spectacular retardedness, this post may well even be the most spectacularly retarded. You know nothing about science. You’ll believe anything, just as long as it helps you not to believe in the greenhouse effect – even to the extent of believing that a lower pH could mean fewer H+ ions being present.
Your science education appears to be based on reading blogs written by idiots, and so you make an enormous fool of yourself frequently. Tell me, just how many scientific papers concerning ocean chemistry have you ever read?
Dissolving CO2 into water does drop the pH and increase the acidity. The reaction is H2O + CO2 yields H2CO3, which then ionizes into a proton and bicarbonate. So at the end of this the total proton load increases and the pH drops. Functionally, adding CO2 to water is the same as pouring carbonic acid into water. The proper question is the one you asked but didn’t answer, how much net effect is there from raising dissolved CO2 by the amount expected in this century. I don’t know the answer to that.
yep I think Nayyer is right, but my chmistry hails from many (20) years ago.
on related notes:
1. air is much less dense than water. There are a lot of H20 molecules in the sea. I mean a lot. It must take an awful LOT of dissolved CO2 to make any difference on ph.
2. remember that ph is logarithmic.
3. I always thought that temperature changes caused balances in the equilibrium states of liquids to change. I thought that increased temp caused sea water to lose its ability to hold CO2…could well be wrong don’t flame me on that…20 years is a long time and i’m sure science has changed in that time. ie rising temp at least partly cause increased CO2?
Adding on to Ali, there is the issue of temperature. Higher overall ocean temp and higher surface temp causing stratification are going to inhibit CO2 absorption. The organic/inorganic carbon cycle ocean is complex. What is being reported as ocean acidification today could be nothing more than what one would expect due to the planet coming out of the little ice age.
This issue is going to be similar to the surface station issue. Those who get to decide where to place sensors, who get to control and interpret data, and who get to design the models, will be the ones who get to frame the debate.
markyg, CO2 doesn’t stay CO2 in the ocean.
CO2 (aq) + H2O H2CO3 HCO3- + H+ CO32- + 2 H+
But the higher the temp, the less CO2 in the air will move in to the water.
I ran the sums once and, if I recall correctly, if the amount of CO2 in the atmosphere increased to 1000ppm (from 385), the pH of the oceans would go from ~8.07 to ~7.97. Given these numbers, it seems a bit misleading (though strictly accurate) to talk about the acidification of the oceans due to increased CO2.
BTW I chose 1000ppm because it is a nice round number and because it is well beyond any reasonable predictions.
Also, my calculations assumed everything else remained equal. Given that we are told to expect an increase in surface seawater temperatures and that warmer temperatures lead to less gas in solution, the result should be less than my calculations suggest.
Just off on a tangent, can anyone suggest what amount of the 280ppm to 385ppm increase in CO2 in the past ~120years is due to increasing temperatures since the Maunder and Dalton minima?
I think you are off about the ‘not adding acid’ part of your analysis, but the point about what makes carbonate dissolve is interesting, and is more important than any problems you may have in your analogy.
As always, the AGW promoters offer misleading information.
Your point about what is more corrosive to carbonate is the fatal omission from our AGW friends.
We actually posted on this subject today also, linking to the same site as you did. Here’s our post:
http://www.c3headlines.com/2009/09/ocean-acidification-another-climate-change-urban-myth-that-climate-alarmists-love-to-scare-journalis.html
Here’s another link that will direct your readers to additional peer-reviewed studies about ocean acidification:
http://www.co2science.org/subject/o/oceanacidification.php
C3H Editor, http://www.c3headlines.com
To Hunter (the one with the capital H),
Hunter>> “Your science education appears to be based on reading blogs written by idiots, and so you make an enormous fool of yourself frequently. Tell me, just how many scientific papers concerning ocean chemistry have you ever read?”
I suggest you attempt to improve *your* science education by navigating to this link:-
http://buythetruth.wordpress.com/2009/03/19/toxic-seawater-fraud/
There you will find references to the scientific papers you seek. eg.
Richardson and Gibbons (2008):
“…no observed declines in the abundance of calcifiers with lowering pH have yet been reported…the role of pH in structuring zooplankton communities in the North Sea and further afield at present is tenuous.”
Vogt et al (2008), experimenting with atmospheric concentrations up to three times current levels,
“…the ecosystem composition, bacterial and phytoplankton abundances and productivity, grazing rates and total grazer abundance and reproduction were not significantly affected by CO2 induced effects.”
Riebesell (2004):
“coccolithophores may benefit from the present increase in atmospheric CO2 and related changes in seawater carbonate chemistry…increasing CO2 availability may improve the overall resource utilization of E. huxleyi and possibly of other fast-growing coccolithophore species…if this provides an ecological advantage for coccolithophores, rising atmospheric CO2 could potentially increase the contribution of calcifying phytoplankton to overall primary production…a moderate increase in CO2 facilitates photosynthetic carbon fixation of some phytoplankton groups…CO2-sensitive taxa, such as the calcifying coccolithophorids, should therefore benefit more from the present increase in atmospheric CO2…”
Gutowska (2008) subjected cuttlefish larvae to CO2 concentrations of 6000 ppm (sixteen times current CO2 concentration), at pH 7.1. Results:
“No differences in soft tissue growth performance were measured between cuttlefish incubated at ~4000 and ~6000 ppm CO2 and controls…Standard metabolic rates of cuttlefish exposed acutely to ~6000 ppm CO2 showed no significant increase or decrease over time…there were no significant differences between the mantle lengths of control cuttlefish and those incubated at 6000 ppm CO2…Interestingly, in the ~6000 ppm CO2 growth trial, the CO2 incubated animals incorporated significantly more CaCO3 [calcium carbonate] into their cuttlebones than did the control group…Functional control of the cuttlebones (i.e. buoyancy regulation) did not appear to be negatively affected by low pH conditions.”
Next time, instead of just sprouting the usual mindless AGW alarmist rubbish, read the post fully to avoid making “an enormous fool of yourself”, as you have obviously done in this instance.
Gee, Hunter is so intelligent that I guess we should just stop debating. His command of the English language and incisive debating skills leave me in awe! </snark off.
Seawater really is an incredibly complex system of ionic interactions, and any model that uses simple calculations of buffering capacity (i.e. freshman chemistry) is going to get it rather wrong. Will increasing atmospheric CO2 change seawater pH? Certainly! How much? Probably quite a bit less than you’d think. How will small decreases in pCO2 in seawater change local biosystems? Worth debating, needs more studying, but it isn’t likely to be huge, unless you are talking about niche systems that are so precariously balanced that almost any change would kill them off.
Firstly, you can learn alot more from past warm periods (empirical data wins out over theory and models am afraid). Studies in the great barrier reef found increased rates of calcification occurred in previous warm periods due to enhanced photosynthesis i.e. the coral grows faster and this obviously offsets any issue with “acidification”. The real thing damaging most reefs is pollution, tourism, commerical fishing etc… deal with these first as they are REAL issues if your concerned about coral reefs!
Secondly, as the ocean warms it will outgass co2, I would imagine this is greater than what is absorbed back due to human addition, the human component is about 3-4% compared to avout 70% from the ocean. Historically co2 has always risen following warming so it makes sense.
The oceans are very complex and to fully understand the future impacts we would also need to know how calcification rates are affected as well as populations of algae, krill, plant life, fish etc…as well as what is happening at the ocean bottom, and trust me, we have no idea! Hence why we should instead look at proxy studies from coral reefs, and these indicate warm is good for coral.
Dont believe that acidification is not a threat? Well then why are corals still alive today when Co2 was around 6000ppm during the Cambrian Era? And yes there were coral reefs back then!
———-
Lough, J.M. and Barnes, D.J. 1997. Several centuries of variation in skeletal extension, density and calcification in massive Porites colonies from the Great Barrier Reef: A proxy for seawater temperature and a background of variability against which to identify unnatural change.Journal of Experimental and Marine Biology and Ecology 211: 29-67.
McNeil, B.I., Matear, R.J. and Barnes, D.J. 2004. Coral reef calcification and climate change: The effect of ocean warming. Geophysical Research Letters 31: 10.1029/2004GL021541.
I’m a complete dumbass.
Great post.
I read that AGW theory slowly dissolves when left in a solution of logic, empirical study and common sense. Could just be something I read on a blog though 😉
The source of the hydrogen ions that is measured as a lowered pH when carbon dioxide is added to water is the water itself. Adding Carbon dioxide lowers the pH of the water by changing the ionic equilibrium in the solution such that there are more hydrogen ions (actually as hydronium ions), than hydroxide ions. Carbon dioxide doesn’t add hydrogen ions, it removes hydroxide ions by forming bicarbonate ions. The result is a new equilibrium in which the [H+] > [OH-], thus a lower pH. This new equilibrium is commonly referred to as carbonic acid, but it is a very weak acid.
The equilibrium involving bicarbonate is sensitive to temperature because carbon dioxide is less soluble in hot water than cold water. As the water is heated, carbon dioxide molecules escape driving the equilibrium backwards and the pH rises toward neutral where [H+] = [OH-].
This is an extreme oversimplification of the acidification of the oceans by carbonation because ocean water is full of many other ions and molecules, some of which serve as buffers that resist changes in pH. Most of these equilibria respond to temperature changes among other things. Furthermore, ocean water is definitely not the same everwhere–in temperature, pressure, or in the oncentration of ions in molecules of various solutes.
Those who argue for AGW and that antropogenic carbon dioxide is making our oceans measurably more acidic ignore the fact that heating carbonated water makes it less acidic.
The increasing amount of carbon dioxide in the atmosphere can be explained by the warming of the oceans due to natural current and climate cycles, geophysical events, and by solar variability. The oceans have generally been warming for about 12 to 15 thousand years, releasing carbon dioxide as it warms. Eventually, it will begin to cool again and we’ll enter another glacial period in which the carbon dioxide content of the atmosphere will be lower.
#
Hunter:
“I’m a complete dumbass.”
September 17, 2009, 1:57 am
Are you sure?
Numb, crass, opinionated, rude, and many expletives too numerous to mention – go you know you like words.
Some tests have been carried out in laboratory conditions which are to my mind of very limited and completely non applicable.
http://news.bbc.co.uk/1/low/sci/tech/7933737.stm
http://www.biogeosciences-discuss.net/6/3087/2009/bgd-6-3087-2009-print.pdf
Warm and benign conditions during the Cretaceous where shallow seas and abundant marine life (coccoliths) were reponsible for the enormous chalk deposits found all over the world, and CO2 levels way above todays values, mean that hysteria over acidity in the sea is somewhat overstated. Over fishing, with consequent disturbance of reefs and pollution (sedimentation) are far more important enemies of marine reefs. Reefs are crucial, as breeding and nursery grounds for young fish, no/barren reefs no future fish stocks.
Warren, this sounds like a good experiment for your son. Two sealed containers of seawater; extra CO2 pumped into one; and measure the effects on simulated seashells.
I predict that there will be no noticeable difference in decay of the seashells.
Adding CO2 to water increases the bicarbonate and carbonate ions (HCO3- and CO3–). That is, it raises the level of dissolved carbonate. That will slow, not increase, the rate at which calcium carbonate dissolves, as well as supplying more carbonate for the coral, etc., to turn into shells.
That analysis does not rule out other effects of added CO2 that could adversely affect the little critters. It won’t significantly affect the PH, but added acid might tend to deplete the alkaline buffering substances, and that might adversely affect coral and shellfish, or the even smaller life forms that they eat. But AFAIK, no such ill effects have been actually linked to CO2 increases. Widespread coral die-offs (“bleaching”) have been reported for a decade or more, but there’s no clear causative link to increased CO2. In fact, coral isn’t dying because it’s CaC03 skeleton dissolves, instead “bleaching” means that the colorfull little animals die and leave behind a white skeleton.
As Stumpy points out, the fossil record shows coral thriving in eras with much higher atmospheric CO2 levels than now. Given this fossil record, CO2 is unlikely to be the culprit in the current die-offs. (Warmer water temperatures could be partly responsible – although many of those fossil coral beds grew when the planet was relatively warm, we generally don’t know how far north they were. And maybe with a little more time it will become clear that the present-day coral isn’t dying out, but shifting northwards…)
First, there are real seashells available.
Second, should the amount of “extra CO2” be realistic? An increase in… maybe 50 parts per million? The smallest size of the containers will be determined by the smallest CO2 container which you can use for measuring.
WIth about 30 gigatons a year being emitted of co2 into the atmosphere per year. Where is the saturation point of co2. Where will the oceans stop absorbing co2.
I would assume that the warmer oceans would stop absorbing sooner than the cooler oceans. Oceans at Hawaii would slow down sooner than the artic.
http://en.wikipedia.org/wiki/Ocean_acidification
Time pH pH change Source
Pre-industrial (1700s) 8.179 0.000 analysed field[3]
Recent past (1990s) 8.104 −0.075 field[3]
2050 (2×CO2 = 560 ppm) 7.949 −0.230 model[2]
2100 (IS92a)[8] 7.824 −0.355 model[2]
This graph suggests to me that saturation has a ways to go.
http://www.sciencedaily.com/releases/2009/09/090915101359.htm
This is suggesting that the consequences may be worse than predicted. I’m finding science usually starts out conservative and then works their way into the strong reality of the situation.
Looks like this is a new area for most people here, so a bit of a ‘learning curve’ to overcome. I found this article that seems directly relevant:
http://www.eoearth.org/article/Marine_carbonate_chemistry
The oceans appear to be basically a carbonate/bicarbonate buffered system, but with all sorts of other stuff dissolved in them. They are also in contact (and hence equilibrium) with carbonate rocks, so are rather different from a simple laboratory buffer solution.
A further point I would like to raise is that marine organisms work against physical equilibria to fix calcium carbonate from dissolved carbonate, using energy to drive the process. They do this on quite a large scale – as far as I am aware all chalk and limestone rocks are created by marine life – so the oceans cannot be described purely by physical equilibria. One of the characteristics of life is that it responds to its environment; my first guess is that marine organisms would respond to increased carbonate dissolution by increasing the rate of deposition.
The CO2 component in our atmosphere is 0.035%. The amount of CO2 in the oceans is 50 times that in the atmosphere. But the total weight of the atmosphere is balanced by the weight of the first (surface)few meters of ocean water. If the atmospheric CO2 goes up from 0.035% to say 0.05%, a new balance will have to be sought between CO2 in the atmosphere and CO2 dissolved in the oceans. So a small proportion of the 0.05% Co2 in the atmosphere will dissolve in the oceans. This will be a fraction of the difference between the original 0.035 % and the new 0.05%, which is a very small amount indeed. Now add this tiny amount to the CO2 gas dissolved in the oceans (which is 50 times that in the atmosphere)and you will get a totally insignificant increase of CO2 in the oceans. Much more CO2 is released from the oceans due to (natural) warming than absorbed by the oceans due to increase of atmospheric CO2 due to whatever reasons, volcanic, anthropogenic, natural biological decay etc.
The acidification of the oceans is scientifically a myth as much as the IPCC’s AGW fairy tale.
Good series of comments here. Sea water is, as others have noted, moderately well buffered to a slightly alkaline pH so whatever (small but appreciable) reduction in pH you would get from any credible increase in the carbon dioxide content in pure water is much reduced once you add those buffers – particularly the carbonate/bicarbonate one.
There is another argument in all this. To be sure. if you add a strong mineral acid you will tend to generate carbon dioxide from calcium carbonate and while dissolving it. However, you are adding not a mineral acud but carbon dioxide and you can’t generate a chemical perpetual motion machine whereby more carbon dioxide in the water generates more carbon dioxide from the shells. It would be an interesting fizzy positive feedback situation.
Hunter,
re⋅tard [ri-tahrd, for 1–3, 5; ree-tahrd for 4] Show IPA
–verb (used with object)
1. to make slow; delay the development or progress of (an action, process, etc.); hinder or impede.
–verb (used without object)
2. to be delayed.
–noun
3. a slowing down, diminution, or hindrance, as in a machine.
4. Slang: Disparaging.
a. a mentally retarded person.
b. a person who is stupid, obtuse, or ineffective in some way: a hopeless social retard.
5. Automotive, Machinery. an adjustment made in the setting of the distributor of an internal-combustion engine so that the spark for ignition in each cylinder is generated later in the cycle.
I am assuming that your are referring to -noun; Slang; 4.b, but it is difficult for me to tell, as I am not nearly the grammatical and syntactical wizard as you.
However, I would suggest that it is you who is the “slow” one here. You missed a fundamental statement, opening sentence “In the past, I have responded to questions at talks I have given on ocean acidification with an “I don’t know.”
And to compound your first mistake, you follow it by disregarding the closing statement “Am I missing something? I am new to this area of the CO2 question, and would welcome feedback.”
Here is where I suggest that it is you who are retarded (ie: slow to learn) by not learning from your first mistake.
On the topic of CO2 into water, PH balance and acidification; Anyone here who owns a pool can tell you that when the water temperature is cool, the PH level rises, when the pool is warm, the PH drops. This, presumably, a side-effect of the gain or loss of CO2 from the surrounding atmosphere. The first thing that always comes to my mind, as it relates to the AGW discussion, if the AGW believers are worried about higher PH levels of the ocean, then they should embrace a warming world, as that would cause a lower PH, not higher.
I personally don’t know a lot about chemistry outside of the fundamentals learned in high school and college, but, through casual observation, it seems to me that the warmer and higher PH level bodies of water tend to harbor higher densities of life as a whole. To me this would suggest two things, 1) that life tends to like warmth, and 2) aquatic life tends to like a little higher PH and more carbonates. These two observations fly in the face of the AGW religious crowd as it suggest that AGW would be beneficial to aquatic life and organic life in general.
I’m making some final preparations for a week long student forum on climate change. I am exploring both sides of the debate, but to be honest with you I do come from the non-skeptic side of the fence, however I do believe that once scientists stop questioning others and even themselves that’s where bad science begins.
With that in mind I hope to put forward opinions from both sides of the arguement, and would appreciate it if I could use some of your posts in my presentation ‘Debunking the climate myths’. If you have anything you wanna add, please post away.
Some of the best will also be added to my blog on New Scientists ‘StudentZone’ which will be launched in the next month.
Finally, I hope that those who contribute will drop the bitching and sniping that seems to be alarmingly prevalent in ths debate, otherwise some heay editing will be in order.
Look forward to reading your comments!
and in quick response to Squidly’s comment “it seems to me that the warmer and higher PH level bodies of water tend to harbor higher densities of life as a whole” and as Jim Turner has quite rightly put “marine organisms work against physical equilibria to fix calcium carbonate from dissolved carbonate, using energy to drive the process”, no, do not forget that increased water temperature reduces the dissolved oxygen content of water, decreasing both its ability to support life, and the remaining communities’ ability to assimilate the input of carbon.
Squidly,
The pool pH changes due to warm water changing things like chlorine. I do not think the changes in CO2 would drive anything close tot he dynamics of a pool’s pH.
And, btw, brilliant work on the troll.
Ecogeek,
Check out where coral reefs live, and then you might wish to rethink the warm vs. cold water.
Good luck on the new site.
I know where they live, it’s called optimum temperatures, chek out the bell curves, just because they live in the tropics, it doesn’t mean they want it any warmer. It’s the same for every organism out there. If the corals can’t find the corrct symbiotic zooxanthellae to exist at a certain temperature, then they cannot perform the photosynethetic part of their energy conversion. Check out coral responses to ENSO cycles.
Please forgive me if my language isn’t as exact as it might be, I didn’t mean cold versus hot, I mean there’s a limit to the stress tolerances of all organisms 🙂
As the temperature of seawater rises, the partial pressure of CO2 rises exponentially. If indeed we are experiencing “global warming”, the CO2 in the atmosphere is the dependent variable, not the independent variable. (This statement assumes that the CO2 given off by rising seawater temperature is much greater than is net CO2 produced on shore).
The amount of CO2 that is presently dissolved in the ocean dwarfs that in the atmosphere. This has been pointed out repeatedly.
I do agree that “The amount of CO2 that is presently dissolved in the ocean dwarfs that in the atmosphere” that is appropriate and natural for the current state of the biosphere,but that doesn’t mean a greater amount would have no effect on the biota!
And your problem with greenhouse gasses is their presence in the atmosphere not in solution, that is an awkward and equaly worrisome symptom of the main problem. And CO2 in WATER would be the independent variable and TEMPERATURE would be our dependent as that should be the changing factor in our theoretical observations.
If you have the time guys, take a read of this paper for what I was saying earlier on Oxygen availability.
Climate Change Affects Marine Fishes Through the Oxygen Limitation of Thermal Tolerance
Hans O. Pörtner and Rainer Knust (5 January 2007)
Science 315 (5808), 95. [DOI: 10.1126/science.1135471]
If you have any that I should have a lok at to put forward for my presentation could you post them, I’m hunting the web, but you guys will know the best places to hit.
Cheers 🙂
I am new to this site, but am greatly encouraged by the debate. Any debate puts paid to the notion that the science on climate change is “settled” and that “consensus” is fact. I am a skeptic. Climate change is occuring and it has always occurred. If not, my city would be under 2kms of ice now. Where did that ice go in the last 10,000 years. According to the AGW theories all mechanisms that controlled climate change in the past are now inactive and only fossil fuel generated CO2 is responsible for climate change. Did the glaciers that covered all of Canada magically evaporate or did the mammoths drive SUVs. According to AGW science either magical wizards removed the ice or mammoths must have driven SUVs. I find it most interesting that every natural history museum has full sections on how ancient climate change affected the earth, the ecosystem and early man and then on a few later panels go on to decry AGW as the latest threat to the planet. Come on people this is ridiculous, the planet and its ecosystem always adapts, survives and ultimately thrives as any review of earth history over the last 600,000,000(Cambrian to present)years clearly shows. Let us concentrate our resources on the eco problems (polluted water, garbage covered landscapes, unregulated stripping of forests and rain forests, air quality etc) that we can do something about and not waste them on a situation that we cannot really affect. Climate change is happening, always has and always will and trying to stop it is like trying to empty the ocean with sand buckets. Last comment: Postulate as you will and argue your postions but let’s cut out the name calling.
I’m a longtime fan of Coyote Blog and Climate Skeptic, but this post was completely untenable.
Adding CO2 to water makes the water more acidic. Period.
Warren’s idea that CO2 is basic because H20 is a reactant for forming bicarbonate is also completely wrong. I don’t think this is a big deal though as I think if someone sat down and explained the chemistry he’d be able to grasp the basics and admit he was incorrect.
Now, speaking to the other side of the isle…
Can someone point me in the direction of an explanation for why (as people have mentioned here) the issue of ocean acidity doesn’t seem to take into affect the rising ocean’s temperatures and how that relates to the Henry’s law constant of CO2?
It seems like there must be a damned good reason. Global Warming Scientists would surely love to say that as the oceans heated up, they’d release more CO2. That’s the sort of positive feedback that their theories rely on. But that is not the dominant theory, so it would seem there’s a good reason why that isn’t the case.
After reading this I decided to go take a look at the IPCC report. It says that while acidification has been predicted, none is yet measured, and that it is very hard to tell the difference between impacts from climate change and decade-scale oceanic oscillations. It also talks about coral bleaching, which has clearly been measured. But again whether that is ENSO or AGW is not easy to say.
You can also go to Wikipedia and search up on ocean acidification to get the case for why the impact could happen. If you want to check out something more serious, search wikipedia for ocean anoxia or anoxic event.
PS – If we don’t do anything to limit ghg emissions, and get seriously into converting coal to oil substitutes after peak oil, 1000ppm co2 equivalent is not implausible in the next century.
This blog is dominated by ignorance and speculation concerning global warming and ocean acidification. So much so that it is difficult to know where to start. Being skeptical is great, but several above seem to think that if they find a quote from a scientific paper that can be used to ‘refute’ warming or ocean acidification, then we should conclude these things are unimportant. This is the same as using a few days when the stock market rose last year to conclude that the recession never happened – it is wrong – read up on the scientific method (which is NOT to search for evidence to support your hypothesis.
As far as ocean carbonate chemistry goes, it is complex, but the acidification part of it is simple enough. Some of those above got it pretty much right. ALthough you may not believe in ocean acidification, your belief does not change the facts. There is no debate about acidification in the ocean. Methods to measure the increase in fossil fuel carbon dioxide by the ocean are so precise that it can be measured very accurately. There is no speculation required. It is undeniable that we have added lots of CO2 to the ocean. It is undeniable (again based on direct measurements) that it is causing the pH (~acidity) of the ocean to decrease (more acidic or less alkaline). Projections of how much more acidic are also large. It is estimated that the surface ocean pH has dropped by 0.1 units since preindustrial times (that is about 25-30% more acidic). Projections by the end of this century are for about another 0.4 units drop, or a 150 to 200% increase in acidity. This is more acidic that the oceans have been for many many millions of years, and the rate of change in acidity is very rapid. We know that the scale of change in ocean pH expected in the future will affect ocean organisms, but the severity of these effects are not known well. We do know that organisms vary in their tolerance to high CO2 levels (low pH). We don’t know how impacts on some groups will affect ocean food webs and ecosystems. Some taxa thrive with higher CO2 levels (mostly photosynthetic organisms). Most animals are stressed by increased CO2 levels, due to disruption of acid base balance, reduced calcification (for some taxa), respiratory stress, and other effects. Much research is focused now on how higher ocean carbon levels will affect individuals species – hopefully we can scale up studies of individuals to populations, communities, and ecosystems, since ecosystem level experiments are difficult. It would be nice to have some ability to predict likely effects of future CO2 scenarios on marine ecosystems and fisheries.
The bottom line – ocean acidification is real whether you like it, or believe it, or not. But we are not yet sure what effects it will have on marine critters. If you want to know more about it, read more of the literature with an open mind, not a mindset searching for a scrap to support your preconceived view. For general reading, find review articles and overview documents (e.g. the Royal Society Report on Ocean Acidification).
James,
Please grant us denialists some links to actually support the long list of claims you make.
Warmer temperatures mean less CO2 in the sea. (That’s part of the reason for increasing atmospheric CO2.) Seawater will become infinitesimally more base, not more acid. In any case, its such a tiny amount it does not matter.
Besides that, temperatures have risen very little, and are now declining slightly. Given the positions of the major Pacific and Atlantic cycles, and the Sun, we can expect more cooling for the next decade or two.
Everyone should relax, we have time to discover more about how the Earth works. Drastic action is not required, and would be extremely foolish and wasteful. Let’s stop the name calling and stick to the science.
I thought the best example was the one where you start with pure water, and then bubble CO2 through it to form hydrogen, carbonate and bicarbonate ions. Yes, the pH goes down. But the number of carbonate ions goes up! Acidity does not necessarily reduce carbonate availability.
Adding CO2 does decrease alkalinity, but it also increases CO3. Adding SO2 or NO2 would tend to increase the concentration of H+ ions, which would shift the CO2 to/from 2H+ + CO3– equilibrium to the left. It’s not simply that the hydrogen was already there, it’s the fact that CO2 forms acid *by making* CO3 ions. And it really the CO3 ions that they’re supposedly worrying about.
It’s analogous to thinking that profits are opposed to taxes. The more tax a company pays, the less profit it can make. So expanding business in the area to boost profits would, by their thinking, reduce total tax revenue. (Profit = CO3, Tax = pH, business = CO2.) The problem is using the wrong measure. If you’re worried about carbonate levels, then measure carbonate levels, not pH.
Besides which, shells evolved in an era when CO2 levels were considerably higher than today, corals have been observed growing near undersea volcanic vents pumping out nearly pure CO2, mussels have been shown to survive quite happily in genuinely acidic conditions (not simply less alkaline), and shelled creatures generally have quite evidently survived levels and changes of temperature, sea level, and acidity over geological time considerably larger than even many of the scare stories, let alone the actual scientific projections, all without going extinct. If they can survive the Eemian, or the post-glacial melting, they probably don’t have much to worry about.
From what we can see ehre, teh AGW alarmists realize that claiming a tiny reduction in alkalinity = acidification is too much of a pile of bs even for them to sell, even setting aside the complete lack of evidence for their panic.
The interesting question is what will be the new source of climate fear?
James, maybe you can provide some references? It would be much more useful than personal attacks and your personal guarantees.
James, I’m not really a denier and I think a lot of what you’ve written about this subject is correct. However the other side does bring up a good point that rising temperatures will reduce the amount of CO2 in the ocean (Per Henry’s Law). So my question, if you’re taking questions, is why are people worried about Ocean Acidification when we’re expecting hire temperatures?
One problem for the ocean acidification panic crowd is that they are too stupid to think skeptics will not check on their abuse of the language.
The pH scale does not have room for acidic and alkali to exist at once.
If something on the alakali side is experiencing lower pH, until it crosses below, 7.0, it is still basic.
It is just less so.
the lack fundamental understanding, and the unwillingness to actually think about stuff or even corroborate the claims of AGW promoters, is one of the hallmarks of AGW true beleivers.
http://www.elmhurst.edu/~chm/vchembook/184ph.html
So for the long winded AGW true believers who declare themselves to be so smart, you might want to check your brainwashing at the door, instead of your brains.
Adding CO2 to seawater, or fresh water, increases the amount of carbonic acid in the sample, pushing it towards the acidic, even though it remains alkaline. It also increases the amount of carbon for marine creatures like coral and shellfish to use in manufacturing calcium carbonate, a primary constituent of their hard bodies.
A simple experiment with dead coral or shells in less alkaline water may show a leaching of carbonate from the shells. But that neglects the living processes whereby the organisms replenish such damage.
More important is the thermal tolerance range of such creatures. It is conceivable that some corals may have narrow temperature preferences, one may ask how they survived previous warm periods. There is some evidence that the algae in the coral polyps has very narrow tolerance to thermal changes, but there are other algaes that enjoy warmer or cooler conditions are willing to take their place, hence the bleaching and unbleaching of certain reefs seen lately.
We have to keep in mind that corals (and all the other hard bodied marine organisms) evolved over hundreds of millions of years. During their existance, temperatures and CO2 levels have been higher and lower than today, often dramatically so. Yet they are still here today.
As has been pointed out in this thread, the major threat to the reefs is bad landuse practices resulting in silt and pollution (read poison) runn-off from adjacent land. Dragnet fishing practices have damaged reefs and sea bottom communities dramatically by physical destruction of organisms. Passing the whole thing off as a result of global warming does nothing to address these solvable problems and may do much to let them off the hook because it diverts attention.
As the sea water temperature warms as we get farther from the “little ice age”, or for any other reason, the partial pressure of CO2 over the water increases exponentially. If this increase is less than the increase in atmospheric CO2 partial pressure due to man or other causes, CO2 would be absorbed by the sea to restore equilibrium. If this increase is greater, then CO2 would go from the sea to the atmosphere. The situation is complicated by such things as ocean CO2 gradients both up and down and from different parts of the ocean which are at different temperatures. The simplistc situation described above probably does not obtain, but the basic principle is correct. Which is cause and which is effect: increased sea temp causes increased CO2 in the air, or does increased CO2 input to the atmosphere cause increased CO2 in the sea? In any case, the ocean surface carbonic acid concentration would be essentially in equilibrium with the CO2 in the atmosphere.
One other thing to consider is the fact that carbonic acid is the way our teeth are recalcified. The process works something like this:
1. Some CO2 from our breath is dissolved into our saliva forming carbonic acid
2. The carbonic acid dissolves calcium in food particles in our mouth
3. The ionic bonds holding the calcium to the carbonic acid are weak and our teeth are able to steal it
Thus we see that carbonic acid aids in the process of building up calcium in one natural system. While coral are not teeth, it is something to think about. I do not remember the reference for this data. If anyone is a dentist please feel free to pipe up!
I’ve not had time to answer any of hte questions posted after my comment until now.
First, some links. Here are a couple links to reports created by experts in ocean chemistry and ocean acidification
http://royalsociety.org/document.asp?id=3249
http://www.ucar.edu/communications/Final_acidification.pdf
“Warmer temperatures mean less CO2 in the sea” Warmer water does indeed hold less gas of any sort, including CO2. But the oceans are NOT saturated in CO2 and thus warming the water does not lead to significant degassing of CO2 from the oceans. As one comment noted, there is considerable variation in the CO2 content of the ocean surface over the globe. THis is due to temperature to some extent, but more to the downwelling (local sinking) or upwelling of waters. Because deep waters almost always have higher CO2 content (due in part to cooler temperature and mainly to the accumulation of respiratory CO2 caused by the oxidation of organic material by animals, bacteria) areas of upwelling are often sources of CO2 that move from the ocean to the atmosphere. Other areas are sinks for CO2. The net flux is naturally about zero. Just as much CO2 enters the ocean as leaves it due to uptake at the surface and its fixation by phytoplankton, and by degassing of deep water CO2 into the atmosphere. The total flux of carbon as CO2 in and out of the ocean is about 90 billion tonnes of carbon (or 330 billion tonnes of CO2) per year. We (mankind) are releasing about 8+ billion tonnes of C (29 Billion tonnes CO2) into the atmosphere yearly. About 1/3rd of this is absorbed by the oceans = ~10 billion tonnes CO2 per year of anthropogenic CO2 (fossil fuel CO2) into the ocean surface. Note that this is about 1 million tonnes of fossil fuel CO2 per hour is absorbed by the ocean surface.
Although some may be skeptical that fossil fuel CO2 is actually absorbed by the ocean, it can be measured very accurately by measuring the stable isotopic ratio of the carbon in a water sample. There are 2 abundant stable isotopes of C. These are 12C and 13C. They exist in a very constant ratio in the ocean, which differs considerably from oil, which is far richer in 13C. Using a mass spectrometer to measure the 12C/13C ratio in a seawater sample, and doing just a bit of math, one can determine the amount of fossil fuel (oil) carbon (or carbon dioxide) in the sample. THis is what oceanographers have been doing for a couple decades, and have documented the inventory of fossil carbon in the oceans. Unlike global warming, which is difficult to unambiguously assign a cause of a change in temperature, we KNOW how much fossil fuel CO2 exists in the ocean. Oceanographers also understand the ocean carbonate system very well, and we KNOW (just as we know 2+2=4) that CO2 is increasing in the oceans due to the addition of Fossil Fuel Carbon, and we KNOW it is make the oceans more acidic.
Some argue (hunter) that the oceans are not getting more acidic and that they are not acidic at all. That is correct, even though hunter is completely missing the point. Ocean acidification is not really the best phrase to describe the change in ocean chemistry that is caused by the increase in total CO2 caused by fossil fuel. The ocean is actually getting less alkaline. But there is nothing magic about alkaline or acidic, except that there are thresholds in its status called the aragonite and calcite saturation state that indicate how easy it is to precipitate calcium carbonate (the 2 major forms created by animals are calcite and aragonite. As the ocean becomes less alkaline or more acidic (choose you own term), the amount of carbonate ions (CO3) is reduced. Carbonate ions are the building blocks for CaCO3, which make up the shells of clams, skeletons of corals, and many other animals and phytoplankton. There is a large body of research now that has shown that as the oceans become less saturated in carbonate ions, calcification is impacted. Corals grow less. If we expose corals to future expected levels of carbonate saturation, some don’t grow. SOme dissolve. That is a major concern.
TJS states that the oceans are now cooling? Where did this come from. The literature (peer-reviewed literature, not newpapers) indicate that global ocean temperatures are continuing to warm. This is pretty undeniable, regardless of any argument over cause. And if you think that my comment about ignorance was name calling, it wasn’t – I meant only that lots of people seem ignorant (i.e. uninformed) about these issues.
STevo; The scenario you describe where pH decreases, but carbonate ions increase, may be possible at some pH levels, but not at any that presently exist in the ocean.
Adding CO2 to seawater causes CO2 + H20 => H2CO3 (carbonic acid) => HCO3 + H+, with some further dissociation to CO3 + H+. But because CO3+H+ => HCO3, is thermodynamically preferred, the extra protons that are produced by adding CO2 to seawater mostly react with any excess CO3. The net result is a reduction in carbonate (CO3) ions with decreasing pH.
I don’t understand the economic analogy. But oceanographers are not simply measuring pH. They are characterizing the entire carbonate system, which includes alkalinity, pCO2, pH, and total dissolved inorganic carbon. Knowing any 2 of these 4 allows one to calculate the others, as well as HCO3, CO3, pCO2, pH, aragonite and calcite saturation states. Carbonate is perhaps the most difficult parameter to measure among these. pH is easier, but can be used as one element to calculate all.
hunter – can you somehow get beyond your whining or at least say something that does more than exhibit how little you understand about these issues?
jnicklin – great comments. But a little off. Although adding CO2 to seawater increases its total carbon content, it also changes the pH and carbonate ion concentrations. It is not completely understood exactly how all organisms calcify, and whether it is the amount of excess carbonate ion available or simply the pH that are key for particular types of calcifiers (e.g. corals, coccolithophores (phytoplankton), foraminiferans, etc. ), but nearly all recent studies that examine rates of calcification in seawater with increasing CO2 (which all have decreasing pH and less CO2) have show reductions in calcification for corals, mussels, crabs, coccolithophores, etc. But NOT ALL have shown this – there have been several exceptions. But there seems to be a higher energetic cost to making calcium carbonate in a more acidic (or less alkaline) ocean – for all of those that calcified more (as well as those that calcified less), they grew less, laid down less organic carbon (e.g. muscle tissue), and most were smaller than the control treatments.
But you point out that temperature is critical – very true. Coral bleaching was first observed in teh 1970s, and is coupled tightly to warm water episodes. It is decimating reefs world wide as we type. There is also concern about multiple stressors – temperature and lower pH may be far worse than just one problem. There is more resaerah addressing this now. And of course other human impacts (fishing, habitat destruction, etc. only add to the problem facing marine ecosystems)
And you correctly point out that the world has been far warmer or has had far higher CO2 levels that exist now. This is absolutely true, and life thrived during these period. But the problem now is that we are changing the pH of the oceans faster and further than has occurred for at least 40 million years, and perhaps far longer. Give thousands of generations, some animals can adapt to higher co2 levels. Some cannot. Corals have disappaered from the fossil record during times of rapid CO2 rises (e.g. the Permian Triassic boundary). Moreover the types of skeletons made by animals has varied through Earth history according to the chemistry of the oceans. For example, aragonite (one form of calcium carbonate) is far more soluble than calcite (another form). Aragonite will dissolve at a higher pH than calcite. – this is one reason that many deep-sea calcifiers make calcite, not aragonite. So our concern is that due to the rapid change in ocean chemistry, some animals may not have the ability (ie.. genetic diversity) to adapt. This is difficult to test experimentally, but the paleorecord is helpful in providing hints. Periods of mass extinctions that have been linked to high atmospheric CO2 (e.g peirod of intense volcanism when CO2 levels rose in the atmosphere and ocean), have often had much higher rates of extinction for calcifying species. These events, though more severe that what we are causing, may be analogous to what is happening now. And if so, these taxa may recover, but it required about 5 million years following an average mass extinction for the fauna to rediversify. That is a long time…
Ted Rado – good comments. The data on ocean chemistry are quite clear that ocean carbon levels are increasing. Fossil fuel influx from the higher Co2 levels of the atmosphere are outstripping any potential loss of carbon from the ocean due to warming. I don’t understand the reason you state that CO2 increases exponentially over the water with increasing temperature .
Take a look at James Orr’s web site (I am not this James). He has several relevant publications on ocean chemistry.
http://www.ipsl.jussieu.fr/~jomce/
Also take a look at NOAA’s ocean acidification page
R STone. I don’t know much about tooth calcification, but I am pretty sure you’ve got this wrong. We need an expert on this to clarify it for us.
http://www.pmel.noaa.gov/co2/OA/
It is time to set Professor Peabody’s “wayback” machine. What year professor? The year 1964, Sherman.
To Miss Coen’s 6th grade science class experiment.
You will need a bottle of calcium rich lime water and a soda straw.
Open the bottle, insert the straw and exhale through the straw so that your breath bubbles up through the lime water. After a few minutes of this you will notice that a white precipitate starts to form in the bottom of the bottle. What is this mysterious substance? Calcium carbonate. Conclusion: carbon dioxide from your breath is dissolving into the water where it is combining with the calcium to form the precipitate. This process removes both the calcium and the carbon dioxide from the solution.
It’s elementary. (Hint: the oceans are full of calcium).
Richard: Miss Coen’s limewater experiment is not relevant to CO2 being absorbed by the oceans’s. Limewater is a solution of calcium hydroxide, and has a very high pH because it contains twice as many hydroxide ions as calcium ions. So when you bubble CO2 through it, CO2 as an acidic gas reacts with 2 hydroxide ions to form carbonate ion, which is the dominant form of CO2 at high pH. Then, when the carbonate concentration has risen high enough to exceed the solubility of CaCO3, solid CaCO3 precipitates.
The pH of the ocean is nowhere near as high, and the most abundant base present in seawater is the carbonate ion. So, when CO2 is absorbed by seawater, the following reaction takes place
CO2 + CO3= + H2O -> 2 HCO3-
THis reaction has a very large equilibrium constant (about 1000) so the favoured reaction direction under most conditions is from left to right. So the effect of ocean acidification by CO2 is to decrease carbonate concentration (and pH), forming more HCO3- (which is already the dominant form of CO2 at seawater pH). Reducing the concentration of CO3= eventually makes CaCO3 liable to dissolution. This is essentiually what ocean acidification is all about.
All of this is elementary chemistry, and as a researcher in the field of CO2 marine chemistry, I am frankly appalled at some of the erroneous arguments put forward on this site. I know many of the authors of the Royal Society report personally, and to suggest that they don;t undertsand basic chemistry is frankly ridiculous.
Keith H,
Chemistry is not just about chemical reactions Keith. Chemical reactions
themselves say nothing at all about the quantities of reactants or products
involved in any process, nor the final effects of the release of those
products.
It is true that chemical reactions predict adding CO2 to sea water will make it more acidic. However, whether the contribution of anthropogenic CO2 will significantly lower the pH of sea water, or have any noticeable effect on calcareous marine organisms is the important question. Especially given the following incredibly small amounts (comparatively) of anthropogenic CO2 compared to the total CO2 in the oceans.
There are also other chemical reactions that act against ocean acidification e.g.
1. The large, natural buffering effect of sea water combined with it’s already relatively high pH (~8.2)
There are several sets of buffering reactions which exist in sea water. One
is the well known carbonate/bicarbonate buffer which many have mentioned here but this buffer is not the only buffer active in the atmosphere/hydrosphere/lithosphere system.
The Earth has a set of other buffering mineral reactions;-
The geochemical equilibrium system anorthite CaAl2Si2O8 – kaolinite Al2Si2O5(OH)4 has, at the pH of ocean water, a buffer capacity which is a thousand times larger than a 0.001 M carbonate solution (Stumm & Morgan, 1970).
In addition we have clay mineral buffers, and a calcium silicate + CO2
calcium carbonate + SiO2 buffer (MacIntyre, 1970; Krauskopf, 1979). All together these buffers give in principle an infinite buffer capacity (Stumm & Morgan, 1970).
2. The fixation of large amounts of dissolved CO2 by marine phytoplankton.
This last point is important and can be summarised in the following overall
net reaction;-
CO2(g) + H2O + Ca2+(aq) CaCO3(s) + 2 H+(aq)
CO2 in the atmosphere is in equilibrium with carbonic acid dissolved in the
ocean, which in turn is close to CaCO3 saturation and in equilibrium with
carbonate shells of organisms and large calciferous deposits in the ocean.
From the equation above it is clear that if the partial pressure of CO2(g) is increased, the net reaction will go towards the right because of the Law of Mass Action. (provided there is enough Ca+2 in solution). This will fix more CaCO3, as the system achieves equilibrium. (This is in fact the source of the world’s massive limestone deposits.)
These two factors combined mean that there is very little chance of increased CO2 levels seriously affecting marine organisms due to ocean acidification, or anything else.
Much research has already supported this conclusion;-
Richardson and Gibbons (2008):-
“…no observed declines in the abundance of calcifiers with lowering pH have
yet been reported…the role of pH in structuring zooplankton communities in
the North Sea and further afield at present is tenuous.” In addition, they write that the “larvae of sea urchins form skeletal parts comprising magnesium-bearing calcite, which is 30 times more soluble than calcite without magnesium,” and, therefore, that “lower ocean pH should drastically inhibit the formation of these soluble calcite precursors.” Yet they report “there is no observable negative effect of pH.”
In fact, they say that echinoderm larvae in the North Sea have actually
exhibited “a 10-fold increase [our italics] in recent times,” which they say has been “linked predominantly to warming (Kirby et al., 2007).” Likewise, they further note that even in the most recent IPCC report, “there was no empirical evidence reported for the effect of acidification on marine biological systems (Rosenzweig et al., 2007)
Vogt et al (2008), experimenting with atmospheric concentrations up to three times current levels:-
“…the ecosystem composition, bacterial and phytoplankton abundances and
productivity, grazing rates and total grazer abundance and reproduction were not significantly affected by CO2 induced effects.”
Riebesell (2004):-
“coccolithophores may benefit from the present increase in atmospheric CO2
and related changes in seawater carbonate chemistry…increasing CO2
availability may improve the overall resource utilization of E. huxleyi and
possibly of other fast-growing coccolithophore species…if this provides an
ecological advantage for coccolithophores, rising atmospheric CO2 could
potentially increase the contribution of calcifying phytoplankton to overall primary production…a moderate increase in CO2 facilitates photosynthetic carbon fixation of some phytoplankton groups…CO2-sensitive taxa, such as the calcifying coccolithophorids, should therefore benefit more from the present increase in atmospheric CO2…”
Gutowska (2008) subjected cuttlefish larvae to CO2 concentrations of 6000 ppm (sixteen times current CO2 concentration), at pH 7.1. Results:-
“No differences in soft tissue growth performance were measured between
cuttlefish incubated at ~4000 and ~6000 ppm CO2 and controls…Standard
metabolic rates of cuttlefish exposed acutely to ~6000 ppm CO2 showed no
significant increase or decrease over time…there were no significant
differences between the mantle lengths of control cuttlefish and those
incubated at 6000 ppm CO2…Interestingly, in the ~6000 ppm CO2 growth trial,
the CO2 incubated animals incorporated significantly more CaCO3 [calcium
carbonate] into their cuttlebones than did the control group…Functional
control of the cuttlebones (i.e. buoyancy regulation) did not appear to be
negatively affected by low pH conditions.”
References:
Stumm, W. & Morgan, J.J. (1970): Aquatic chemistry. An introduction
emphasizing chemical equilibria in natural waters. John Wiley & Sons, 583 pp.
MacIntyre, R. (1970):”‘Why the sea is salt.”, Scientific American 223 (5),
104-115.
Krauskopf, K.B. (1979): “Introduction to geochemistry”; 2nd edition.
McGraw-Hill, Inc., 617 pp.
Richardson, A.J. and Gibbons, M.J. 2008. “Are jellyfish increasing in
response to ocean acidification?” Limnology and Oceanography 53: 2040-2045.
Riebesell, U. 2004. “Effects of CO2 enrichment on marine phytoplankton.”
Journal of Oceanography 60: 719-729.
Gutowska M. A., H.-O. Pörtner, Frank Melzner. (2008) “Growth and
calcification in the cephalopod Sepia officinalis under elevated seawater
pCO2”
Keith H,
I think you are fibbing about who you are, what you do, and who you know.
The basic thing is that to claim something is ‘acidifying’ when it is not makes you less than truthful.
The other is that you write like a troll, not a serious worker.
Perhaps you know those researchers as you clean their offices, but you do not know them as peers.
I attempted to post this a couple days ago, but it failed.
First, some links. Here are a couple links to reports created by experts in ocean chemistry and ocean acidification
http://royalsociety.org/document.asp?id=3249
http://www.ucar.edu/communications/Final_acidification.pdf
“Warmer temperatures mean less CO2 in the sea” Warmer water does indeed hold less gas of any sort, including CO2. But the oceans are NOT saturated in CO2 and thus warming the water does not lead to significant degassing of CO2 from the oceans. As one comment noted, there is considerable variation in the CO2 content of the ocean surface over the globe. THis is due to temperature to some extent, but more to the downwelling (local sinking) or upwelling of waters. Because deep waters almost always have higher CO2 content (due in part to cooler temperature and mainly to the accumulation of respiratory CO2 caused by the oxidation of organic material by animals, bacteria) areas of upwelling are often sources of CO2 that move from the ocean to the atmosphere. Other areas are sinks for CO2. The net flux is naturally about zero. Just as much CO2 enters the ocean as leaves it due to uptake at the surface and its fixation by phytoplankton, and by degassing of deep water CO2 into the atmosphere. The total flux of carbon as CO2 in and out of the ocean is about 90 billion tonnes of carbon (or 330 billion tonnes of CO2) per year. We (mankind) are releasing about 8+ billion tonnes of C (29 Billion tonnes CO2) into the atmosphere yearly. About 1/3rd of this is absorbed by the oceans = ~10 billion tonnes CO2 per year of anthropogenic CO2 (fossil fuel CO2) into the ocean surface. Note that this is about 1 million tonnes of fossil fuel CO2 per hour is absorbed by the ocean surface.
Although some may be skeptical that fossil fuel CO2 is actually absorbed by the ocean, it can be measured very accurately by measuring the stable isotopic ratio of the carbon in a water sample. There are 2 abundant stable isotopes of C. These are 12C and 13C. They exist in a very constant ratio in the ocean, which differs considerably from oil, which is far richer in 13C. Using a mass spectrometer to measure the 12C/13C ratio in a seawater sample, and doing just a bit of math, one can determine the amount of fossil fuel (oil) carbon (or carbon dioxide) in the sample. THis is what oceanographers have been doing for a couple decades, and have documented the inventory of fossil carbon in the oceans. Unlike global warming, which is difficult to unambiguously assign a cause of a change in temperature, we KNOW how much fossil fuel CO2 exists in the ocean. Oceanographers also understand the ocean carbonate system very well, and we KNOW (just as we know 2+2=4) that CO2 is increasing in the oceans due to the addition of Fossil Fuel Carbon, and we KNOW it is make the oceans more acidic.
Some argue (hunter) that the oceans are not getting more acidic and that they are not acidic at all. That is correct, even though hunter is completely missing the point. Ocean acidification is not really the best phrase to describe the change in ocean chemistry that is caused by the increase in total CO2 caused by fossil fuel. The ocean is actually getting less alkaline. But there is nothing magic about alkaline or acidic, except that there are thresholds in its status called the aragonite and calcite saturation state that indicate how easy it is to precipitate calcium carbonate (the 2 major forms created by animals are calcite and aragonite. As the ocean becomes less alkaline or more acidic (choose you own term), the amount of carbonate ions (CO3) is reduced. Carbonate ions are the building blocks for CaCO3, which make up the shells of clams, skeletons of corals, and many other animals and phytoplankton. There is a large body of research now that has shown that as the oceans become less saturated in carbonate ions, calcification is impacted. Corals grow less. If we expose corals to future expected levels of carbonate saturation, some don’t grow. SOme dissolve. That is a major concern.
TJS states that the oceans are now cooling? Where did this come from. The literature (peer-reviewed literature, not newpapers) indicate that global ocean temperatures are continuing to warm. This is pretty undeniable, regardless of any argument over cause. And if you think that my comment about ignorance was name calling, it wasn’t – I meant only that lots of people seem ignorant (i.e. uninformed) about these issues.
STevo; The scenario you describe where pH decreases, but carbonate ions increase, may be possible at some pH levels, but not at any that presently exist in the ocean.
Adding CO2 to seawater causes CO2 + H20 => H2CO3 (carbonic acid) => HCO3 + H+, with some further dissociation to CO3 + H+. But because CO3+H+ => HCO3, is thermodynamically preferred, the extra protons that are produced by adding CO2 to seawater mostly react with any excess CO3. The net result is a reduction in carbonate (CO3) ions with decreasing pH.
I don’t understand the economic analogy. But oceanographers are not simply measuring pH. They are characterizing the entire carbonate system, which includes alkalinity, pCO2, pH, and total dissolved inorganic carbon. Knowing any 2 of these 4 allows one to calculate the others, as well as HCO3, CO3, pCO2, pH, aragonite and calcite saturation states. Carbonate is perhaps the most difficult parameter to measure among these. pH is easier, but can be used as one element to calculate all.
hunter – can you somehow get beyond your whining or at least say something that does more than exhibit how little you understand about these issues?
jnicklin – great comments. But a little off. Although adding CO2 to seawater increases its total carbon content, it also changes the pH and carbonate ion concentrations. It is not completely understood exactly how all organisms calcify, and whether it is the amount of excess carbonate ion available or simply the pH that are key for particular types of calcifiers (e.g. corals, coccolithophores (phytoplankton), foraminiferans, etc. ), but nearly all recent studies that examine rates of calcification in seawater with increasing CO2 (which all have decreasing pH and less CO2) have show reductions in calcification for corals, mussels, crabs, coccolithophores, etc. But NOT ALL have shown this – there have been several exceptions. But there seems to be a higher energetic cost to making calcium carbonate in a more acidic (or less alkaline) ocean – for all of those that calcified more (as well as those that calcified less), they grew less, laid down less organic carbon (e.g. muscle tissue), and most were smaller than the control treatments.
But you point out that temperature is critical – very true. Coral bleaching was first observed in teh 1970s, and is coupled tightly to warm water episodes. It is decimating reefs world wide as we type. There is also concern about multiple stressors – temperature and lower pH may be far worse than just one problem. There is more resaerah addressing this now. And of course other human impacts (fishing, habitat destruction, etc. only add to the problem facing marine ecosystems)
And you correctly point out that the world has been far warmer or has had far higher CO2 levels that exist now. This is absolutely true, and life thrived during these period. But the problem now is that we are changing the pH of the oceans faster and further than has occurred for at least 40 million years, and perhaps far longer. Give thousands of generations, some animals can adapt to higher co2 levels. Some cannot. Corals have disappaered from the fossil record during times of rapid CO2 rises (e.g. the Permian Triassic boundary). Moreover the types of skeletons made by animals has varied through Earth history according to the chemistry of the oceans. For example, aragonite (one form of calcium carbonate) is far more soluble than calcite (another form). Aragonite will dissolve at a higher pH than calcite. – this is one reason that many deep-sea calcifiers make calcite, not aragonite. So our concern is that due to the rapid change in ocean chemistry, some animals may not have the ability (ie.. genetic diversity) to adapt. This is difficult to test experimentally, but the paleorecord is helpful in providing hints. Periods of mass extinctions that have been linked to high atmospheric CO2 (e.g peirod of intense volcanism when CO2 levels rose in the atmosphere and ocean), have often had much higher rates of extinction for calcifying species. These events, though more severe that what we are causing, may be analogous to what is happening now. And if so, these taxa may recover, but it required about 5 million years following an average mass extinction for the fauna to rediversify. That is a long time…
Ted Rado – good comments. The data on ocean chemistry are quite clear that ocean carbon levels are increasing. Fossil fuel influx from the higher Co2 levels of the atmosphere are outstripping any potential loss of carbon from the ocean due to warming. I don’t understand the reason you state that CO2 increases exponentially over the water with increasing temperature .
Take a look at James Orr’s web site (I am not this James). He has several relevant publications on ocean chemistry.
http://www.ipsl.jussieu.fr/~jomce/
Also take a look at NOAA’s ocean acidification page
R STone. I don’t know much about tooth calcification, but I am pretty sure you’ve got this wrong. We need an expert on this to clarify it for us.
http://www.pmel.noaa.gov/co2/OA/