In the final episode, Becky and Emily wrap up with wisdom from the Blue Planet team and hear the thoughts of children who are learning about protecting the environment.
Marine biologist and acoustics expert, Steve Simpson, talks about the intricacy of recording the delicate sounds of the clownfish. He reveals that it can be very noisy underwater.
Sir David talks about his hopes and fears about the future of our oceans and shares his optimism for the young people who are forcing politicians to do things to protect it.