Ocean acidification

[4wd]

What to make of this, i find this analysis that CO2 has next to no effect on ocean PH very convincing.
http://wattsupwiththat.com/2013/07/08/ocean-acidi-what/

The concluding points:

1. It is Interesting to note that we somehow have an accurate measurement of ocean acidity from 200 years ago when the apparatus to measure pH was only invented in 1924 and it wasn’t conceived as a measurement until 1909. It should be impossible to conclude within .1 pH unit the actual oceanic pH 200 years ago.

2. The maximum possible change from atmospheric CO2 pre industrial to today is less than .001 pH units, it is thus impossible to measure

3. Even if we could measure .001 pH units there are plenty of questions on the accuracy and calibration techniques associated with the measurement

3. It is impossible for CO2 to deplete carbonate ions in solution

4. Rivers and freshwater lakes are more susceptible to carbonic acid from atmospheric CO2, so why are we worried about the oceans?

5. It is essentially chemically and biologically impossible for carbonate dependent organisms to suffer from CO2 increases

6. Carbonic acid is not the same as hydrochloric or acetic acid.

7. pH from carbonic acid tells us nothing about the CO2/Carbonate system

8. There have been no experiments to demonstrate harm, only hypothesis and models.

9. The experimental framework for testing carbonate organisms with increasing CO2 is easy, yet unperformed

10. The organisms most susceptible to ocean acidification from CO2 evolved at a time when concentrations were 15 times higher than today.

11. Ocean acidification means nothing if the rate at which CaCO3 is being produced exceeds the rate at which carbonic acid consumes it.

12. The buffer capacity of the ocean is huge and incorporates carbonic acid, further demonstration of CO2 overwhelming this buffer is needed.

 

[Devonian]

I like his point one. By similar logic small periods of time didn't exist before clocks were invented. As to the rest, well as ever I'll listen to the experts, oceanographers, ocean scientists, ocean chemists, first.

Edited July 10, 2013 by Devonian

[knocker]

I have a book by C.P. Summerhayes and S.A. Thorpe, "Oceanography". It contains a complex detailed chapter, "The Marine Carbonate System", and when i say complicated I mean complicated, And I don't recognize too much of what I've just read. I could go through it in detail I suppose but like Dev. I think I'll just stick to the peer reviewed papers I've read.

 

EDIT

I will just add this.

 

An increase in atmospheric C02 increases the total amount of inorganic carbon within the sea. While this increases the buffering capacity, it also induces a slight increase in the ocean's acidity and thus acts to oppose further entry of the gas.

 

The pH of sea water varies over a surprisingly narrow range, centred at pH 8±0.5. The most important point is that the dissociation of carbonic acid (H2C03) forms a buffering system, which may be summarised by the general weak acid-conjugate base equilibrium, equation (12.2), which results in a solution pH given by equation (12.3), where K. is the equilibrium constant for the dissociation reaction. Small additions of acids or bases alter the ratio of anion (HC03-) to acid (H 2C03) only slightly, and have little effect on the pH of the solution. The buffering capacity is the extent to which the pH is changed by a given addition of acid or base. The higher the concentration of carbonic acid, the greater the buffering capacity. 

(note I haven't bothered with the equations)

 

Reproduced courtesy of the above.

Edited July 11, 2013 by knocker

[knocker]

I've had another quick glance at this and ignoring his irrelevant mutterings about fresh water experiments he goes on to say, To tackle ocean acidification you need to understand chemistry; pH, alkalinity, buffers, etc. A self-evident comment but I see no explanation of alkalinity and one of buffers is very shaky. Anyway this if it's of any interest.

 

 

 Definitions of alkalinity and dissolved inorganic carbon

 

The alkalinity, A,, of sea water is the combined negative charge due to hydrogen carbonate (HC03) and carbonate ions (CO_3^2-), expressed in molal concentrations. Alkalinity is based on sea water being electrically neutral and is determined by titration (and therefore given the subscript t). In practice, the alkalinity is the amount of acid (hydrogen ions) needed to convert all the anions back into their respective un-ionised acids. The alkalinity equation expresses electroneutrality between the positively and negatively charged ions, equation (12.13), which can be rearranged to give equation (12.14), where [sA). the surplus alkalinity, is the concentration of all weak acids other than boric and carbonic acids The second and third ionisation constants of boric acid are very low, so that boric acid is the major contributor to A, from the borate system. In sea water, ([OH-) - [H•]) and the amount of SA are small,so equation (12.14) may be simplified, to give equation (12.15). SA cannot be ignored in anoxic regions, when sulphide, ammonia, and phosphate concentrations may be very high.

 

Typical values for the alkalinity of sea water are given Table 12. 1. The carbonate alkalinity, CA. is the contribution to alkalinity from carbonate and hydrogen carbonate, equation (12.16), and is normally obtained by subtracting the borate contribution from A,. The borate contribution, [b(OH)₄.-1. is obtained from the expressions for total boron, B_t, and the equilibrium constant for boric acid dissociation, K6, equations (12.17)-(12.19). These equations are also a function of salinity, pressure, and temperature.The borate contribution is usually 3-5% of CA.

 

The total dissolved inorganic carbon concentration, DIG, is defined as the concentration of all of the dissolved forms, and is given by equation (12.20). Note that the terms ([HC03-] and [CO_3^2-]) refer to the total equilibrium concentrations and include contributions from ion pairing with Na•, Ca2+, Mg2•, etc. (see Box 12.3). There are other weak acids and bases that are potential contributors toward the alkalinity of sea water, but under typical conditions their concentrations are extremely small; thus, their contributions are usually much less than 1% of A, and can be ignored in the above calculations. (In the oceanographic literature, total alkalinity is sometimes referred to as TA or simply A; carbonate alkalinity as Ac; total carbonate as TC02, TIC, or L,C02.)

 

At the pH of most ocean waters, less than 1% of the inorganic carbon exists as ([C02(aq)] + [H2C03]), and the H2C03 concentration is only about 0.2% of that of C02(aq).

 

It is important to remember the definition of alkalinity as the concentration of hydrogen carbonate and carbonate ions. It is not a measure of the pH or how alkaline sea water is. Once this is recognised, it is easy to appreciate that sea water alkalinity and acidity change in the same direction: where the DIG is high, so are alkalinity and acidity (low pH); conversely, where the DIG is low, so are alkalinity and acidity. (my emphasis).

 

One of the few places where inorganic precipitation of calcium carbonate occurs is on the Bahamas Banks, where the sea is shallow and warm, and salinity is high (exceeding a salinity of 37). The warmer and more saline the water, the lower the solubility of gases, including C02. The concentration of CO/- is also large, and often rises sufficiently for the water to be supersaturated with respect to CaC03, so that the inhibiting effect of the MgC03 ion-pair is overcome, and small crystals of calcium carbonate (in the form of aragonite) are precipitated. In these conditions, the term (A, - DIG) is large.This helps to explain the apparent contradiction that when the DIG is high, calcium carbonate is more likely to dissolve, and vice versa.

 

(I've left the equations out)

 

 

 

 

Source

 

C.P. Summerhayes, S.A. Thorpe, "Oceanography", Wiley

Edited July 11, 2013 by knocker

[Methuselah]

I've had another quick glance at this and ignoring his irrelevant mutterings about fresh water experiments he goes on to say, To tackle ocean acidification you need to understand chemistry; pH, alkalinity, buffers, etc. A self-evident comment but I see no explanation of alkalinity and one of buffers is very shaky. Anyway this if it's of any interest.

 

 

 

Source

 

C.P. Summerhayes, S.A. Thorpe, "Oceanography", Wiley

He has the appearance of being a bit of chancer, knocker - all bluff and bluster. A bit in the Monckton mould, perhaps?

[knocker]

He has the appearance of being a bit of chancer, knocker - all bluff and bluster. A bit in the Monckton mould, perhaps?

 

I googled him to find out who he was and nothing obvious appeared but didn't spend that much time on it. As you say Pete, or is it Robin? Anyway it's such a complicated subject along with the chemistry of the oceans it's impossible to sum up in a few paragraphs. IMO anyway.

[Methuselah]

I googled him to find out who he was and nothing obvious appeared but didn't spend that much time on it. As you say Pete, or is it Robin? Anyway it's such a complicated subject along with the chemistry of the oceans it's impossible to sum up in a few paragraphs. IMO anyway.

Indeed, knocker...I spent months working through all those oceanic CO2/carbonic acid/calcium carbonate/aragonite equilibria; and I never drew his conclusions...And, whoever said that 'carbonic acid is [...] the same as hydrochloric or acetic acid', for heaven's sake?

[4wd]

Just because it was on Watts doesn't mean there must be something fundamentally wrong or misleading to discover.
Also the background checks to see if he might be funded by Koch didn't work I see.  

whoever said that 'carbonic acid is [...] the same as hydrochloric or acetic acid'
He referring to the misleading demonstration video to simplify the 'official' stance on what might be going on.
You need to read the article not just the summary.
 

[knocker]

Indeed, knocker...I spent months working through all those oceanic CO2/carbonic acid/calcium carbonate/aragonite equilibria; and I never drew his conclusions...And, whoever said that 'carbonic acid is [...] the same as hydrochloric or acetic acid', for heaven's sake?

 

Quite and why is a further demonstration of CO2 overwhelming this buffer needed?. The buffer doesn't have to overwhelmed to increase acidification. It's part of the whole complex system.

[knocker]

Just because it was on Watts doesn't mean there must be something fundamentally wrong or misleading to discover.

Also the background checks to see if he might be funded by Koch didn't work I see.  

 

 

Funny enough I wanted to see whether he was an oceanographer although I'd already placed my bets.

[laserguy]

I'm more concerned about the pH of me homebrew than the oceans. It's a right bugger to get it correct - chucking alkalis in to make it more acidic an' stuff. Anions, onions,cations, pH buffers - it's enough to drive a man to drink!