A Cultural History
First edition: That's gotta be Richard Powers! (Checking ISFDB.org: Confirmed.)Aquanaut in yellow: I was cautiously guessing Dean Ellis, but then I noticed a faint signature at the bottom right. David K. Mattingly. (ISFDB is silent, but the owner of the painting confirms it here.
Cheers Bill, I've updated this post and the other two with your intel. Much appreciated