Planet Earth III

Episode
Episode 2 - Ocean
Broadcast Info
2023 (59 mins)
Description
Much of our world remains virtually unexplored, for most of it is underwater. The ocean covers two thirds of the planet and is home to eighty per cent of all animal life, yet we know little about it. Presented by David Attenborough, this ground-breaking film journeys through the vast and varied ocean to reveal the extraordinary behaviours and adaptations required for life here. The shallow seas of the tropics may look like a paradise, but they are a battlefield, where even predators like the deadly lionfish must beware... Nothing is what it seems! The clown frogfish, the reef’s most extraordinary hunter, carries a fishing rod on its head, baited with a shrimp-like lure which can prove fatally seductive. Away from the tropics, in the cold waters off North America, the sun fuels forests of giant kelp. It is a dangerous place for young horn sharks - giant sea bass and large sharks patrol through the kelp, but the real danger is buried beneath. A little horn shark unwittingly stumbles into the ambush of the angel shark. With a lightning strike, it is swallowed whole, but it is not over yet - the little horn shark has a secret weapon. Winter storms can batter the forest and rip the kelp from the seabed, casting it away into the open ocean. Out in the big blue, the floating kelp becomes a vital lifeline for animals such as flying fish, which use them to lay their eggs - but they must lay thousands, because these eggs are on the menu for hungry blue sharks. Life in the vastness of the open ocean relies on these islands of seaweed, but today they are being replaced by something altogether different. Plastic. Every year 12 million tons ends up in the ocean. It is lethal to many, but some animals are learning to take advantage of these plastic rafts - meet the Columbus crab. An open ocean creature with a big problem. Columbus crabs are poor swimmers so to find a mate they must hitch a lift. Passing turtles can help, and in fact provide a permanent home for a pair of crabs. In return the crabs provide an onboard grooming service - a relationship that works so well, these turtles are often home to a devoted Columbus crab couple. Finding a partner in the ocean is not always easy. In the Sea of Cortez, mobula rays perform astounding, acrobatic leaps to attract other rays - resulting in a gathering of vast numbers. All the noise, however, attracts a family of specialist ray-hunting orca that have a unique strategy to catch the fast and agile rays. The least known parts of the ocean are its great depths. To venture there requires specialised vessels to withstand the crushing pressure. As you leave the surface behind, sunlight fades and you enter an alien world, encountering a massive siphonophore, longer than a blue whale, and a gulper eel with huge jaws that can engulf prey larger than its own body. By the time you reach the seabed two miles down, the temperature has dropped to near freezing - so cold the eggs of a mother pearl octopus would take over 10 years to develop. She heads to a special place where warm water escaping from the seabed creates a thermal spa. She is joined by twenty thousand female octopus all here to raise their eggs - the largest known gathering of octopus on planet earth. The warm water speeds up her eggs’ development, but it will still take two years and in that time this devoted mother will not leave them - not even to feed. It is an extreme effort that will eventually kill her. In today’s ocean, animals are having to compete with us. Off the coast of Chile, South American sea lions have learnt clever techniques to raid fishermen’s nets - which they now do in their thousands, but it comes with a huge risk. As the net is drawn in, the sea lions must get out quickly or they risk being crushed and drowned. Sadly, the inexperienced young and pups don’t get out in time, and some pay the ultimate price. Animals have evolved in remarkable ways to the demands of life in the ocean. But can they now adapt to the new challenge... living alongside us?
Genre
Science; Natural History

How to cite this record

The Open University, "Planet Earth III". https://learningonscreen.ac.uk/ou/search/index.php/prog/247245 (Accessed 10 Jan 2025)