|As the oceans absorb more and more CO2, they
may become more acidic and that grave consequences can be expected. Recent
measurements suggest that this is somewhat the case. But what is the story?
Should we be alarmed? How much is known and how much is not? Is ocean acidification
another hoax, a swindle, or do we need to pay serious attention? What are
the threats to the oceans? How does ocean acidification work? What is the
carbon cycle? In this chapter we will try to foster an in-depth understanding
of the CO2 processes in the ocean and where present science fails.
Scientists' overwhelming consensus about ocean acidification is deeply disturbing, as if there exists no doubt; as if there are no uncertainties; as if we know it all. It is equally worrisome that this chapter is the ONLY place in the world where doubts and uncertainties are raised. Our ignorance exceeds knowledge by a wide margin. It's never time not to be skeptical.
|An introduction to ocean acidification and what this chapter is all about (located on this page) (8 pages)|
|The conclusion is on this page, but go to the two other parts first.|
|the main part for understanding ocean acidification and the reasoning behind it, deals with the carbon cycle, how acid the oceans are and by how much it varies, evidence of acidification, the carbonate system and why it is feared that acidification could cause disaster. (31 pages)|
|part 3 mentions all the missing science, uncertainties and misconceptions. It gives a good idea of where the science of ocean acidification is at and how much credence we can attach to the many fears that have been published. (3 pages)|
|Learn how the global climate works and why the IPCC is wrong. Very extensive and important for environmentalists. (140 pages)|
|Corrupt scientific institutions and their rogue scientists. It is time to hold individuals to account and to mention their names. Corruption is always about individuals. A collection of absurd articles. (10 pages)|
|Glossary of terms used; cutting through the gobbledegook. (on this page)|
|Books, publications, references and links (on this page)|
|A log of recent changes to this section (on this page)|
& related chapters
|DDA: the Dark Decay
Assay and ecological discoveries made with a pH meter.
pH meter: how does a pH meter work?.
sea water: what sea water contains, including atmospheric gases. Important for this chapter.
periodic table of elements and a chemistry primer to allow you to understand the chemistry in this web site.
Table of the important elements for life, in the universe, planet, plants, animals.
Threats to land, sea and air: a summary of the many threats created by human activity.
Geologic time table: ages and periods of life on earth and earlier (7 p)
Science needs skeptics: understand how scientists, searching for new discoveries, are also afraid when they are found by others
Science, technology and human nature: the three forces that destroy the planet are expected to save it too. Optimism? Madness?
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The oceans have an 'acidity' measured on a pH scale of around 8.0, a figure larger than neutral pH=7.0, which means that they are alkaline or basic. The word alkalinity thus means the opposite of acidity. The pH of the oceans has been a mystery and remains a mystery because it depends on many factors. For instance, oceanographers think that the alkalinity of the sea depends on a chemical balance with rocks, particularly limestone rock. From this one can compute that the ocean's pH should be around 8 and that it has not varied by much over hundreds of millions of years.
|One of the important variables in this chemical balance is carbon dioxide CO2. As CO2 dissolves in water, the water becomes mildly acidic (clean rain water has a pH=5.6 to 6; in the diagram 5.7), enough in fact to dissolve calcium from soils and to create dripstone formations inside caves while it evaporates. Intuitively one may think that a doubling in CO2 would result in a doubling of acidity but this is not the case as this graph shows. Without CO2, pure rain water would have a neutral pH of 7.0, and that is where the graph begins on left. Initially CO2 is very willing to dissolve, thereby rapidly acidifying the otherwise pure water, but eventually this slows down. The red dot is placed at the current situation with CO2 around 350ppm at average temperature and pressure. From here a doubling in CO2 will contribute to a much reduced acidification of only 0.15 pH units or an increase in acidity of around 30%. Note that this is not just a theoretical curve but has been measured by titration. This behaviour of CO2 also applies to sea water, but here the situation is much more complicated due to the buffering effect of limestone.|
CO2 'binds' with water like: CO2 + H2O <=> H2CO3 <=> H+ + HCO3- <=> H+ + H+ + CO32-
In this equilibrium equation the double arrow <=> means 'in balance'
(equilibrium) or that the chemical reaction can move both ways. The symbols
H, O and C stand for hydrogen, oxygen and carbon and their numbers are
given by the digit following. The superscripted + and - and 2- symbol denotes
their ionised states with loose electrons. In the right hand side are more
H+ ions, which are measured by a pH meter as 'more acidic'.
Of the four 'states' that CO2 can assume, carbondioxide CO2 is a mere 1%,
bicarbonate HCO3 is 93% and carbonate CO3 8% . But the total amount of
carbon dissolved in the oceans is just short of 40,000Gt (Pg) compared
with less than 700Gt in the atmosphere. The sea is a massive carbon dioxide
reservoir, in balance with an even more massive limestone reservoir of
40,000,000Gt carbon in marine sediments .
|Note that the above equations depend somewhat on pressure and also on temperature. The graph shows how CO2 dissolves according to temperature in an atmosphere of pure CO2, but degassing can be assumed to behave similarly for lesser concentrations (60/2000= 3% per degree C; some say 4%). Applied to an ocean of 38,000 Gt CO2, would equate to 1140Gt/ºC or 12/44 x 1140 = 311GtC/ºC. Note that gigaton Gt, one billion metric tonnes, is the same measure as petagram Pg, but we'll use Gt in this chapter and that the atmospher now holds about 700Gt carbon. [To convert from CO2 to C, multiply by 12/44.] Note also that these measurements hold for pure water and 100% CO2 and are not necessarily valid for sea water and low concentrations of CO2. Note also that human emissions are about 7GtC per year.|
This equation is a gross simplification of the seawater system because seawater has many more elements that are likely to play a role. One of these is Calcium (Ca2+) which 'binds' with CO3 like: Ca2+ + CO32- <=> CaCO3 to form limestone as in corals and shells. There exist several forms of limestone, but this is only a finer point (aragonite, calcite, magnesium calcite, ...). The production of limestone by organisms is called calcification. De-calcification on the other hand can be done either by organisms who calcify (echinoderms for instance) or those who dissolve limestone (boring sponges, worms, molluscs, many bacteria) and it can also happen chemically without organisms (coral sand dissolving back into sea water).
It is thought that the carbondioxide in the sea exists in equilibrium with that of exposed rock and bottom sediment containing limestone CaCO3 (or sea shells for that matter). In other words, that the element calcium exists in equilibrium with CO3. But the concentration of Ca (411ppm) is 10.4 mmol/l and that of all CO2 species (90ppm) 2.05 mmol/l, of which CO3 is about 6%, thus 0.12 mmol/l. Thus the sea has a vast oversupply of calcium. It is difficult therefore to accept that decalcification could be a problem as CO3 increases. To the contrary, it should be of benefit to calcifying organisms. Thus the more CO2, the more limestone is deposited. This has also been borne out by measurements (Budyko 1977).
The bit missing at the beginning is that CO2 (atmosphere) <=> CO2 (sea water) or in other words, that the carbondioxide in the air is in balance with that in the surface water, which has not been proved. Note in this respect that rising water temperatures will expel CO2 from this huge reservoir and in doing so, also raise acidity.
It is reasoned that if the amount of CO2 in the atmosphere rises, then
more of it will dissolve in the water, working all the way through the
chemical reactions, to an increase in acidity and an increase in carbonate
CO3. Scientists believe that the sea in pre-industrial times was 'saturated'
relative to dissolved limestone, and that recent increases in CO2 have
'desaturated' the sea (beginning in the antarctic sea), with possible dire
consequences for sea life. But we have observed that calcium skeletons
dissolve back into what scientists call 'saturated' CO3.
|A valid comment from
a reader, Feb 2008
Dear Dr. Anthoni,
I read part
of http://www.seafriends.org.nz/issues/global/acid.htm and I believe a
found a significant flaw in it.
I used basic equilibrium equations for ion dilution and found that the concentration of Ca2+ is proportional to the square of the concentration of H+ (acidity) and inversely proportional to the partial pressure of carbon dioxide. Now, because the concentration of bicarbonate is immensely greater than the concentration of H+, an increase of 10% in the pressure of carbon dioxide will result in basically an increase of 10% in the concentration of H+. Because the concentration of calcium grows with the square of the concentration of H+, that would result in an increase of 10% in the concentration of Ca2+. Now, what that means is that the calcium would come from rocks or from biological calcium carbonate. By the way, the problem is that the concentration of CO3 would decrease, and not increase. The sea would effectively suck the CO3 from the organisms, releasing their Ca2+. So, you are right in that an increase of CO3 would not be a problem, but an increase in CO2 would produce a decrease in CO3.
much CO2 comes down in rain?
Assuming that a pH of 5.6 of a raindrop is caused by CO2, this equates to 1.18E-5 mol/L ~ 1.2E-2 mol/m3. Total average annual rainfall on Earth is estimated at 990mm ~ 1m [Wikipedia], and the surface of our planet is 510E6 km2 = 5.1E14 m2. Thus total annual rain volume = 5.1E14 m3, containing 6.1E12 mol CO2. One mol CO2 = 44g or 4.4E-5 tonne. Thus in all rain, the amount of CO2 that rains down is 268E7 t = 2.68 Gt = 0.73GtC. Which is a very small amount and part of the 'balance' between ocean and atmosphere.
propagated by scientists and the mainstream media:
My personal experience with acidity in the ocean stems from many pH measurements that led to the discovery of half a dozen elementary ecological laws that, if confirmed, would turn the whole acid ocean debate on its head. It would in fact send most publications on this subject to the dustbin. That was in 2005, and mainstream scientists have not reacted since. So let's review what these discoveries are about (read the DDA chapter):
Since it was first published, a tsunami of me-too publications have seen print, but objective analysis from a wide angle of perspective, is still missing. Most scientific articles are not free, as if scientists have so much to hide. But fortunately the two most important ones are still free, Impacts of ocean acidification .. report of a workshop by NSF, NOAA, USGS (PDF) by J A Kleypas et al. and a clumsy report from the Royal Society UK: Ocean acidification due to increasing atmospheric carbon dioxide (PDF) but which has high educational value. Much has been done with computer models, but these are only as valid as their underlying assumptions, and can neither be proved right nor wrong.
Note1: In upwelling areas,
cool deep water reaches the photic (light-) zone. This water is more acidic
and it also contains nutrients. Those nutrients were produced from sinking
biomatter that became decomposed by bacteria, in darkness underneath the
photic zone. As the nutrients became available as soluble salts, also the
water became more acidic (less alkaline). In the process, also more CO2
dissolved into the water. When the deep water reaches the surface, the
nutrients start plankton blooms which also make the water more alkaline,
which in turn limits productivity. However, it is observed that upwelling
areas remain relatively acidic, thereby promoting productivity. It could
also be that a high turnover of nutrients, possible by active planktonic
decomposition, lowers pH in upwelling areas.
It is assumed that you have read part 2 carefully and part 3 cursorily (superficially) before reading the conclusion here, so read it again later.
Nothing in the sea works as expected:
its physics, chemistry, biochemistry, physiology, biology and ecology do not work as thought;
truth is often opposite to intuition.
The sea is weirder than we can possibly imagine.
To learn about the sea, forget what you were taught at school, open your mind and begin from scratch.
It is an important message that I want you to take home and keep in
the back of your mind whenever you read about marine science or planetary
science. It is a message for scientists too.
Dead planet thinking: most oceanographers, physicists, chemists treat the planet as a dead planet, where every force, every process can be described and captured in an equation, and then simulated by a computer. But life frustrates every attempt, as it corrupts equations, while also adapting to changing circumstances. Of all these, the sea is the worst with its unimaginable scale, complexity and influence. We may never be able to unravel the secrets of the sea.
Opening with these thoughts, the (bio)chemistry of the sea is so complicated and unknown that the scare for acidic oceans is entirely unjustified. It is true that humans should act from a position of humility and prudence, adjusting to nature while never exploiting more than 30% of the environment but we have gone far over that limit. Today nature is adjusting to us and we cannot change that without a much smaller human population and much less waste (CO2 is part of human waste). Well, that is not going to happen. So we have to accept that nature is now changing. An important part of that is an increase of the life-bringing gas carbondioxide. With higher CO2 levels, plants will produce more. Hopefully the world will become warmer too, and all this is welcome to the starving billions. As oceans become more acidic, they will become more productive too, adjusting to the new scenario. There will be no 'tipping points' but there could be some unexpected and unforeseen surprises. The world has been changing and adapting to major changes since it came out of the last ice age, and the changes caused by fossil fuel will be relatively small.
As far as the science of ocean acidification goes, there are some major errors and conflicts, and the amount of missing knowledge is much larger than what we know. Scientists have uncritically accepted the findings of the IPCC with critically low 'pre-industrial' levels of CO2, but has anyone tried to grow plants and seedlings at 180ppmv CO2?
Kleypas et al (2006) state "It is certain that net production
of CaCO3 will decrease in the future", and then place at highest priority
for future research "Determine the calcification response to elevated
CO2 in . . [just about every marine organism with a shell]", and "..
many cases even the sign of the biochemical response, let alone the magnitude,
is uncertain". Clearly this is an unscientific and contradictory
statement in the light of present ignorance (not knowledge). Their advice
is to do more studies in elevated CO2, but will they also look at reduced
levels of 180ppm (the hypothetical pre-industrial level)? It is not in
their list of recommendations.
Will they also evaluate my own discoveries of slush and symbiotic decomposition by which organisms live inside a 'cocoon' of lower pH for higher productivity? Not likely - they have ignored it completely since 2005.
What annoys me is that an entirely hypothetical threat is blown up out
of all proportions, while at the same time the foremost threat to our seas,
that of degradation (eutrophication), remains insufficiently acknowledged
and investigated. In the world's degrading coastal seas, many questions
can be studied that also relate to ocean acidification, for acidification
is also a symptom of degradation. What is the main threat to the world's
coral reefs - hypothetical decalcification or actual degradation?
|If this chapter has been of use to you, tell others, as many as you can, so that they too may benefit. Link to this page to help people find it. And if you are financially comfortable, consider making a donation to encourage this work.|
|Glossary of terms
Here is a short list of the strange words used in this chapter. For a glossary on marine science, read /books/glossary.htm and for geology /books/geogloss.htm
anthropogenic: (Gk: anthropos= human being; genere=to
create) man-made, in the case of carbon dioxide, by burning fossil fuels,
burning forests, degrading soils, making cement, etc.
aragonite: (from Aragon, a place in Spain) a needle-like (orthorhombic) crystal structure of limestone CaCO3 with some variations, as produced by most molluscs and corals. Aragonite dissolves more easily than calcite.
aragonite horizon: aragonite is the kind of limestone that shells are made of. It dissolves into seawater if the concentration of carbonate ions CO3 is too low. The boundary concentration is called the aragonite 'horizon', which becomes more pronounced with depth. Note that this entirely a hypothetical concept, the relevance of which to calcifying organisms, has not been demonstrated.
calcification: turning calcium and carbonate ions into hard calcium carbonate (calcite) or similar hard limestone (aragonite)
calcite: another word for calcium carbonate, laid down by organisms like coralline algae, some sponges, some plankton organisms, and many others. It may occur as fibrous, granular, lamellar, or compact. Marble is a form of calcite.
calcite horizon: calcite is a hardy form of calcium carbonate (see above). It dissolves when the concentration of carbonate ions becomes less than the calcite horizon. The calcite horizon has a lower concentration of carbonate ions than the aragonite horizon because calcite does not dissolve as readily. Note that this is an entirely hypothetical concept.
DIC: Dissolved Inorganic Carbon: all inorganic carbon molecules and ions like CO2, HCO3, CaCO3. It also contains slush and dissolved polysaccharides and any biomatter that passes through filtration paper (e.g. small bacteria and viruses).
equilibrium: many chemical reactions can go both ways, resulting in an equilibrium that can be disturbed.
magnesium calcite: a soft limestone that includes magnesium ions Mg in the place of calcium Ca.
nacre: the mother-of -pearl limestone inside shells. Nacre does not decalcify (dissolve) as readily as calcite and aragonite.
polysaccharides: a collective name for sugar-like molecules including storage polysaccharides such as starch and glycogen and structural polysaccharides such as cellulose and chitin. In the sea the protective slime of organisms is often made of polysaccharides. Many kinds of polysaccharide exist.
RDOC: Recalcitrant or Resistant Dissolved Organic Carbon, a collection of biomolecules and other particles that resist being decomposed by natural bacteria, equivalent to the substance named slush by us (see below)
sequestration: (L: sequestrare= to commit for safekeeping) the process by which substances are taken out of circulation, as in the carbon cycles.
slush: (slush as in partly molten snow, named by Floor Anthoni) a collection of short biomolecules that remain as a result of incomplete decomposition. For some reason these molecules are difficult to decompose into nutrients without an additional source of energy. The most simple of these is perhaps dimethylsulfide CH3.S.CH3. Dimethylsulfide (DMS) is a cloud forming molecule that plays a decisive role in the Earth's temperature regulation. Note that scientists discovered Recalcitrant Dissolved Organic Carbon (RDOC) about a decade ago. It is probably identical to our slush. (see publications supporting or refuting Anthoni's findings)
The scientific literature and Internet are awash in articles relating to ocean acidification, mainly as part of a world-wide scare for global warming. Most are repeats of what others wrote, superficial and scare-mongering, and not worthy of mentioning here. Of the scientific articles, most are not freely available. So, here is a collection of the ones worthy of your attention.
Budyko, M I (1977): Climatic changes. Am Geophys Union, p 128. Budyko, M I: Global Ecology.1980 Caldeira, K and M Wickett (2003): Anthropogenic carbon and ocean pH. Nature 425: 365. (not free) but available from http://www.thew2o.net/images/folder/PDF%20Ocean%20Observers/Ocean%20Acidification%20November.pdf. Computer simulations based on assumptions. No experiments. http://pangea.stanford.edu/research/Oceans/GES205/Caldeira_Science_Anthropogenic%20Carbon%20and%20ocean%20pH.pdf Doney, Scott C (2006): The dangers of ocean acidification. SciAm March 2006. (not free) A grossly exaggerated account. Freely, R A et al. (2004): The impact of anthropogenic CO2 on the CaCO3 system in the oceans. Science, 305, 362-366. (not free) Henderson, C (2006): Paradise lost. New Scientist 5 August 2006 :29-33. (not free) Idso, Craig D (2009): CO2, global warming and coral reefs: prospects for the future. http://scienceandpublicpolicy.org/originals/co2_coral_warming.html free PDF (81 pages). An excellent review of published science confirming that corals adapt well to warmer seas, rising seas and acid oceans. In fact, they love it! Must-read! Jacobson, Mark Z (2005): Studying ocean acidification with conservative, stable numerical schemes for nonequilibrium air-ocean exchange and ocean equilibrium chemistry J. Geophys. Res. Atm., 110, D07302, April 2, 2005. Extensive equilibrium calculations based on known equilibrium constants, assuming that the ocean is in equilibrium with the atmosphere. Scenarios for 275, 375, 750ppmv CO2 and 0-25ºC. Computer model for future pH. Kleypas J A et al. (2006): Impacts of ocean acidification on coral reefs and other marine calcifiers. Free from www.isse.ucar.edu/florida/www.ucar.edu/communications/Final_acidification.pdf (10MB, free) An honest account, including uncertainties and missing knowledge. A must-read. Unfortunately focuses on calcification rather than ecosystem functioning. Also gives an historic timeline and chronicles all organisations involved. Orr, James C., Victoria J. Fabry, Olivier Aumont, et al. (2005): Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms. Nature, 437, 681-686. (not free) Computer simulations based on assumptions. No experiments. http://www.ipsl.jussieu.fr/~jomce/acidification/paper/Orr_OnlineNature04095.pdf Robinson Arthur B , Noah E Robinson, and Willie Soon (2007): Environmental effects of increased atmospheric carbon dioxide. J Am Phys & Surg (2007) 12, 79-90. An objective account showing strong correlation of temperature and solar activity, both recent and in past centuries. Also shows effect of CO2 outgassing from the oceans. http://www.oism.org/pproject/s33p36.htm Oregon Institute of Science & Medicine (free HTM & PDF) Royal Society UK, Raven, J A et al. (2005): Ocean acidification due to increasing atmospheric carbon dioxide. The Royal Society Policy Document 12/05; 55pp; available free at http://www.royalsoc.ac.uk/displaypagedoc.asp?id=13539 Educational but a dishonest account, failing to mention uncertainties and missing science. Lacking experimental facts. "Ocean acidification is a powerful reason, in addition to that of climate change, for reducing global emissions of CO2 to the atmosphere to avoid the risk of irreversible damage to the oceans. We recommend that all possible approaches be considered to prevent CO2 reaching the atmosphere. - excellence in science -" [sigh] Sabine, C L et al. (2004): The ocean sink for anthropogenic CO2. Science, 305, 367-370. (not free) a novel tracer method for tracing anthropogenic carbon dioxide in the oceans. Makes far-reaching conclusions. Sarma, V, T Ono, T Saino (1971): Increase of total alkalinity due to shoaling of aragonite saturation horizon in the Pacific and Indian Oceans: influence of anthropogenic carbon inputs. Geophys Res Lett 29, 1971. Wikipedia article 'ocean acidification' http://en.wikipedia.org/wiki/Ocean_acidification Written by the scaremongers without balance. Provides many links to suppportive science and many media articles and even an upcoming scare movie. A link to the Seafriends balanced article is consistently removed. No doubting or uncertainties allowed! Acid Test: the global challenge of ocean acidification (movie) - a new propaganda film by the National Resources Defense Council, fails the acid test of real world data. By Dr Craig D Idso, Jan 2010. http://scienceandpublicpolicy.org/images/stories/papers/originals/acid_test.pdf (free)
NOAA (National Oceanic and Atmospheric Administration) educational section about severe weather phenomena.