Thanks for putting your post in context, Seden33. It makes it all a bit clearer.
In regard to the pH in different areas of the ocean I have no idea directly, needless to say. However I expect the researchers are able to measure pH quite accurately. (More accurately than I can measure pH in my fishtank :D)
As I understand it, the PNG reefs were of interest because they provided some insight in a 'live example' of what could potentially happen if the oceans as a whole acidified to the same extent.
Your find was a good one and now I understand why you posted it, I agree with you that it has some relevance.
