I have a place up the road and during the summer visit this was a much discussed subject with locals, expats and visitors alike. Several salient points arose, firstly the whole area used to be a swamp - some parts still are, a dolphinarium type structure is big, very big, and you would need an awful lot of concrete to be poured just to make sure it wouldn't sink. If it did start to sink then it would crack and from my knowledge of hydraulics this would let the water out! Equally it would also need two rather large pipes to the sea, one for clean seawater in and one for foul seawater out. Try as we might no one could identify a suitable route for these pipes from the sea to the proposed site - although with enough money you can achieve most things.
This is another idea doing the rounds that generates topics for the forum. Now I have heard that there are plans for a F1 circuit in Uzumlu . . . . . . . .