Some of that hoopla surrounds the finding that a small drop in pH will prevent some marine organisms from producing a shell.  Lower pH being more favourable to the dissolution of carbonates, the shell seems to dissolve faster than it is produced.
Good point.  I read that article also and did a little investigation of my own.

Here is a great article that describes what you are talking about.

The Chart on Page 11 says it all.
Maybe SS can spiff if up a bit.