Hmmmm....."the strange dark patches" at the top....
The picture is taken at an island in a fjord on the west coast of Norway. Partly, the patterns on the top are reflections from the mountains on the other side. But there is more....
The version I posted was made in January (when the picture was taken). I had to go back to the original to find out - and realised that the file I posted is a file I played with to add more texture/air on the top. It looks a bit strange - rather sloppy finish. I normally wouldn't publish a file like that.
The "original" version can be seen at http://www.pbase.com/jazzfoto/image/97439973