And lets say this life is intelligent. It floats in this Great Ocean.
What would this life need? Well, since this life is a mix of solid and liquid, thus it would need some solids and liquids to replenish itself.
Obviously, the liquid is all around this life and there is no problem with it's supply, but solids would mainly be at the bottom of the ocean and saturated in the liquid as well but in lesser amounts.
Therefore, the main resource needed by life would be the solid state. In other words the life in this ocean would need pure elements of solids to exist. All these minerals, solts, etc, would be greatly valued by life in the Ocean..
But the problem is that all of that solid is at the bottom which is hard to reach due to density, since it is UNDER the bottom of the ocean.
Not only that, but the minerals are not in a pure form, they are "oxidised" and combined with other minerals.
That means that not only the minerals have to be mined from under the bottom of this ocean but also they have to be refined.
And this is not a simple task for life in the ocean.
But since the life is intellegent it would think and come up with a solution how to mine and refine these mineral.
What is ver interesting is that it is very hard to refine any mineral inside liquid. You would actually need a low density environment to allow for fairly pure refinement.
That calls for some enclosed system which would have that low density, gaseous atmosphere, where it would be suitable to refine minerals from any mixed state.