Replies

It's pH is 5 something, as is distilled water that's been exposed to the atmosphere.

Precisely.

Seawater pH is 8.1+/-0.1, that's good enough. Calling a change within that range acidification for the purposes of justifying "serious problems" for coral is flat out BS.

Sorry that you don't get it. A small shift in the pH of seawater means a large shift in the saturation state with respect to calcium carbonate (shifting the equilibrium toward bicarbonate and away from carbonate ion). Reducing the seawater concentration of carbonate ion makes calcification a much more difficult physiological process for the organisms to accomplish.

Not BS. Basic marine chemistry.

Once all the components of the system are included, there is no net change in CO₃^2-, because the increase in CO2 causes an increase in dissolution.

Not in surface waters. Surface seawater is currently 6x supersaturated with respect to CaCO₃. Acidification drastically lowers the supersaturation state, making calcification much more difficult, without causing any significant dissolution aspects to kick in. There might be a few places where the surface waters actually bedome undersaturated with respect to aragonite, which will be tough on the aragonitic species. Deep-sea dissolution won't have an immediate effect; wait a couple thousand years maybe, and it might.

IOWs pH does not depend on alkalinity in the real system, it depends on the saturation conc of the alkaline earth components Ca and Mg and all the various dissociation constants.

Ca and Mg don't vary nearly as much as carbonate ion.

Re: Seawater pH is 8.1+/-0.1, that's good enough. Calling a change within that range acidification for the purposes of justifying "serious problems" for coral is flat out BS.

"Sorry that you don't get it. A small shift in the pH of seawater means a large shift in the saturation state with respect to calcium carbonate

You're doing the same thing i pointed out was done in htat paper. You think the matter's covered by alkalinity, but as I pointed out, it's not.

"Reducing the seawater concentration of carbonate ion makes calcification a much more difficult physiological process for the organisms to accomplish."

No, not more difficult. It takes slightly longer. In fact if you read the damn paper, you'll see they're puzzle why the corals grow anyway, regardless of their simplistic understanding of the matter.

"Not BS. Basic marine chemistry.

The presentation of the chemistry is faulty and the whole "corals are in serious trouble" claim is BS.

Re: Once all the components of the system are included, there is no net change in CO₃^2-, because the increase in CO_{2_{causes an increase in dissolution.}}

" Not in surface waters."

What do you mean, not in surface waters? Coral grows in shallow water on a lime bed, in and around sources of Ca, so it will dissolve locally, as I said.

"Surface seawater is currently 6x supersaturated with respect to CaCO3. Acidification drastically lowers the supersaturation state, making calcification much more difficult, without causing any significant dissolution aspects to kick in.

Nonsense. The words "drastic" and "much more difficult" don't apply, and the corals agree.