As it says on the tin.
<<<REMOVED partial screenshot after reading comment from Stardock Staff elsewhere>>>
Checking the XML file, it appears all three Aquatic Biosphere improvements have been set to Player Wonder instead of Colony Unique.
Not going to post all three improvements, but here is a sample of part of the first improvement:
It should be: <IsColonyUnique>true</IsColonyUnique> for all three.
Found this messing around with the new campaign, for what it is worth.
I suppose I could have been misreading things and it's that Aquatic Races get one tile period, empire wide, per tech age. If so, fair enough and ignore this post. Not really sure of the utility of it then, as three extra tiles empire wide really doesn't seem like that much of a benefit, especially on maps larger than Small.
But I suppose that's a discussion for another time.