I've read that this is a known problem...the underwater domes will be floating above the lagoons when you start the game. I'm not sure if my issue is related, but ever since I've tried using the underwater domes, the game will crash every couple of minutes. I deleted the domes (they're not worth the trouble) to see if the game will still crash. I haven't played since last night when I noticed the problem, so we'll see if the domes are crashing the game.