For my fantasy world, I have what I think is a really cool idea. The world is flat, and elliptical in shape. If you touch the silvery edge, well, let's just say bad things will happen. (Not relevant...) This edge is an impenetrable, indestructible wall.
This world is like a coin, with two sides. Each side is the same (for the purposes of the question), and the giant island slopes downward until it meets itself. This leaves most of the ocean without a solid floor.
Assume that gravity is magically inclined to drag everything down to the equator of the "coin". with 1g of force, and this gravity is the same all around.
The world has a high "ceiling" of sorts, above each surface, uniformly heating and lighting each side of the coin. ~72°F
That is the full extent of the world, no sun, moon, or stars for you to be concerned about.
If an object sunk into the sea, it would sink until it reached the bottom of the oceans, a mile from each surface. A fish happily swimming on one side would appear upside down from the other.
My question is, how would aforementioned changes affect the ocean?