Also, here's the thing with the deep ocean. Assuming heat flow is linear (straight up or straight down), and maybe that's a really shitty assumption...
We know the Earth's mantle is super rough ridin' hot relative to the water temperature, and we know the surface temperature should average 60 or 70 degrees F worldwide...so I'd guess there is a steady temperature gradient from the depths to the surface. Apparently this isn't true and I wonder why.