OK, I've seen something like this. When we were cruising off the coast of Somalia, I was hard at work on my ship after sunset (OK, I was fishing) and I fell asleep for about 5 hours. When I woke up around 1AM, the sea was as white as milk. It was really freaky; like I was in some alternate universe (Because the sea at night is pitch black). I went up to the "Smoke Box" and asked my pals what the heck was going of and they thought it was either methane or CO2 bubbles.
It didn't explode when we tossed our butts over the side, either.
My $.02
