Whilst not denying the possibility of methane bubbles, the websites quoted are hardly awe inspiring scientific facts....
One is an article about an article published in the other (that itself offered no concrete proof) and another has this exceptionally stirring quote,
This explains why ships are lost in the Bermuda Triangle, but it doesn't explain why planes are lost there as well. According to the Navy, the Bermuda Triangle is one of two places on earth where a magnetic compass points to true north instead of magnetic north. A navigator who didn't compensate for that "could find himself far off course and in deep trouble," according to the Navy website.
Hmmmm.