If you stop to think about it the whole idea of 'sea level' bogus. The earth may SEEM to be 'rock solid' to us..but it's not. The reality is that the earth is a YUGE molten gob...with a thin crunchy crust on top...the earth is spinning like a gyroscope...and wobbling (due to sciency things).

If you've ever had the 'pleasure' of watching a fat lady jog down the street...you kinda get the idea of what the 'skin' of the earth is doing...on a much grander scale.

Whelp...the ocean is just sitting there...like sweat on that gal jogging...
it's gonna be affected as well.