The acid test

I'm confused. In the post you link to above, JPL found that pH changed by 0.1, but this video claims that 'ocean acidity' (they make no difference between shallow or deep waters as opposed to the JPL paper) has increased by 30%. A change from pH 8.2 to 8.1 is less than 1% change in pH, however. So where is the 30% number coming from? H+ concentrations?

Yep.
(Though the numbers here are rounded and real values differ by location and other factors).

pH is a log scale.
Here an item in [square brackets] means concentration.

By definition [H3O+] = 10^(-pH)

At pH 8.1: [H3O+] = 10^(-8.1) = 7.9x10^-9
At pH 8.2: [H3O+] = 10^(-8.2) = 6.3 x10^-9

The absolute difference is:
(7.9x10^-9) â (6.3x10^-9) = 1.6x10^-9

The relative difference is:
(1.6x10^-9) / (6.3x10^-9) = 0.25 = 25%

...sorry, that's a pH change of less than 2%, not 1%.

so if they are discussing H+ concentrations, a doubling of 'acidity' reduces the pH to just under 7.9 in specific areas.

How does a basic solution dissolve calcium carbonate?

Max,

Because different substances have different solubility/dissolution constants, none of which are dependent on the arbitrary division between an acidic and basic solution.

Calcium carbonate exists in equilibrium with bicarbonate ion and several other species, including aragonite and calcite. The equilibrium state of each species depends on the H+ ion concentration.

V.I., according to Wikipedia's entry on carbonic acid, there is not an equilibrium between CO2 and carbonate ions. The fully protonated acid is in equilibrium with CO2. It seems rather weird to me to say the least. There is also a table of pH's and the concentration of the different carbonate ions, but it only goes up to pH=7. At that point the carbonate ions have concentrations on the order of 10^-9 molar or less. How do such small concentration affect solid calcium carbonate in rather high concentrations in shells?

Here's the wikipedia entry:

http://en.wikipedia.org/wiki/Carbonic_acid

Here we go - ocean acidification, the next big fraud. The oceans have often been absorbing and releasing far more CO2, and the slight rise of CO2 of recent times is essentially meaningless.

Hi Peter.

Did you get a chance to think about my earlier questions about your link to McIntyre?

Very nice, but I'm disappointed that it didn't mention the possible consequences of letting sulfate-reducing bacteria run wild with the Oceans' biomass.

Has anyone seen any research on the pH we'd have to get to for significant HS blooms?

"The oceans have often been absorbing and releasing far more CO2, and the slight rise of CO2 of recent times is essentially meaningless." - POS

Maybe not so meaningless:

http://e360.yale.edu/content/feature.msp?id=2241

"A new study says the seas are acidifying ten times faster today than 55 million years ago when a mass extinction of marine species occurred. And, the study concludes, current changes in ocean chemistry due to the burning of fossil fuels may portend a new wave of die-offs"

There is an interesting and disturbing paper in the current edition of the Proceedings of the National Academy of Sciences of the USA, which examines the effects of increasing ocean acidification on the behaviour of some fish species. The link to the paper is here:

http://www.pnas.org/content/early/2010/06/24/1004519107.full.pdf

This is from the abstract:

"....we use a combination of laboratory and field-based experiments to show that levels of dissolved CO2 predicted to occur in the ocean this century alter the behavior of larval fish and dramatically decrease their survival during recruitment to adult populations. Altered behavior of larvae was detected at 700 ppm CO2, with many individuals becoming attracted to the smell of predators. At 850 ppm CO2, the ability to sense predators was completely impaired. Larvae exposed to elevated CO2 were more active and exhibited riskier behavior in natural coral-reef habitat. As a result, they had 5â9 times higher mortality from predation than current-day controls, with mortality increasing with CO2 concentration...."

These results are not based on modelling (for those of you who are of the mistaken belief that there is something wrong with using models). These results are based on actual trials under a variety of environmental conditions, and show concusively that under certain conditions, the behaviour of some species changes dramatically, such that they actually seek out their predators, with obvious consequences (although the behaviour of the predator has not been modelled, and would make an interesting experiment in itself).

So an increase of CO2 makes some fish think predators smell nice thats amazing. Do they explain how it does this or do they just show a correlation between fish smell and CO2 levels?