I just blew one of the pictures up in PS, and there has been some doctoring, but I don't believe it is completely faked. Mostly what I noticed was some smudging (as they noticed), and perhaps something was done with the acropora at the top, some of the edges of the clam at the top don't look completely natural at high magnification.
It's also possible that they did some color enhancement with the blues, but I can't tell for sure.