Vertical ocean biomes

What: Make the top layer of ocean warm ocean and the bottom deep ocean.

Why: It would simulate differing ocean pressure as you go deeper and more specifically the different fauna and geography at different levels. It would also imply there was an ice age as in real life there is a line where the shoreline was before glaciers melted. Also it would make good use of the new vertical biomes.

How: Below y 45 have all ocean become cold ocean.