Here some interesting videos on the marine environment:
Shifting Baselines – A video about the Decline of the Marine Environment
The End of the Line – A documentary about the impact of overfishing on our oceans
Capt. Charles Moore on the seas of Plastic – TED, Ideas worth spreading
Peter Tyack: the intriguing sound of marine mammals – TED Ideas worth spreading, 2010
The Blue Planet: Seas of Life, BBC Documentaries, 2002, narrator: David Attenborough, ASIN: B001957A4E