I managed to get down to the beach last night just before dark and experimented a little with the camera.  This is a 30 second image of Sandbridge Beach in Virginia Beach (The Sanctuary condos in particular) taken from the middle of Sandbridge Pier.  It was taken at the tail end of sunset, and the lights from the pier illuminated the water in the foreground. The yellowish lights from the pier mixed with the blueish water made for greenish water in the foreground. Yellowish + blueish = greenish. And Mother Nature provided the sunset color.