[Mind Bender]

Hi,
And thanks for reading this! Last weekend I traded of a couple of acoustics for a Washburn D12S-12, a 12 string acoustic. It handled very nice! And it didn't sound bad at all either. Even though the strings looked, and sounded like they came with the guitar when it was new. I brought it home and played on it for an hour or so. I set it down and when I sat there looking at it, I noticed a crack running from the bridge to an inch or so away from the bottom edge. I felt it there while I was playing, but couldn't see it at all. So I thought it was something spilled on it that needs to be cleaned off.
Is there anything that should be done to it now? Or wouldn't a crack like that weaken the guitar at all?
Thanks again.