From the first moment a wave washes over you and the camera dips below the water to reveal the wonderful world of coral-filled seas inhabited by myriads of strangely beautiful and oddly fierce creatures, you will feel lucky to have got there without getting wet and while able to breathe on your own.
The deep sea is, of course, a big-fish-eat-smaller-fish world, and a Mantis-shrimp-eat-shellfish world, and a Giant Pacific octopus-eat-crab world, and the movie can't do anything to disguise that's mostly what goes on down there. It can only make it more palatable by having Johnny Depp (best known to kids as Captain Jack Sparrow from "Pirates of the Caribbean," and Kate Winslet, best known to everyone as Rose, who didn't go down with the "Titanic") narrate simple information in reassuring chatty voices about how that's what keeps nature in balance. Of course, besides inevitable death, a lot of reproduction also keeps nature in balance, but there's not much of that seen in this movie, except for a remarkable moment when all the coral (which, perhaps because they happen to look more like plants than creatures related to jellyfish and sea anemones, are deemed safe sexual objects) spawn at the same moment.
Tucked in too is a brief verbal nudge about stopping over-fishing the seas, as that destroys the environment. But what conveys that message much more strongly than words are the remarkable images captured by Howard Hall and his crew in oceans around the world. Danny Elfman's score is suitably evocative, although it's sometimes upstaged by the very loud crunching of something with very big teeth eating something whose shell wasn't quite tough enough to save it.
Take the plunge. This is one instance where it's totally delightful to feel like you're swimming with sharks. Starring assorted sea creatures. Narrated by Johnny Depp and Kate Winslet. Directed by Howard Hall. Produced by Michele Hall and Toni Myers. An IMAX release. Documentary/Large-Format. Rated G. Running time: 40 min