The sky is WAY too over-exposed... try lowering your aperature and using a longer shutter speed. I feel that this helps me bring out the closer things (trees and the rest of the green) while not over-exposing the sky as much.
I think the sky looks better, but personally I would like to see some detail in the trees. Thats what I tried to bring out in the version I photoshopped.
I really like those underwater pics. Considering I know absolutely nothing about underwater photography take this at face value.
1. I assume your using a flash and I think its overexposing the lighter features.
2. Your focus is off (not bad just off)
hope you post more. I really enjoy sea life pics.