I'm a total newbie to video and just did my first two small kdenlive "projects" with footage shot during my dives in European lakes and stone pits. I hope you will enjoy them. The original footage was 1080p FullHD (Traunsee) and 720p HD (Halle). This is not the usual warm water diving, this is diving in 8°C nutrient-rich water. However, Traunsee has a several minute scene swimming with a swarm of perchs in shallow, "sunny" water.

Traunsee/Austria: http://www.youtube.com/watch?v=ShdUjAkER2s
Halle/Germany: http://www.youtube.com/watch?v=ojDvxKqj1_w

Thank you to the developers for working on kdenlive, which proved to be very useful to me noob!