During the rerun of "LA X, Part II" before "What Kate Does" airs, I noticed that the scrolling information bar said that the springs in the temple are natural springs on the island, and that the temple was built around it. I'm also going to argue that the springs are no longer clear because of the death of Jacob (which I feel was plainly obvious, but please feel free to argue against it). I know it's probably already obvious that Jacob and the island are very strictly bound together, but this is definitely still significant as supporting that claim.
I didn't really have any more to say on that except that I had kind of an "oh man..." moment when I saw that. Any thoughts or comments?