Transcript for 'Blue Planet' captures the fascinating behaviors of underwater creatures
It's the awe-inspiring new series taking a deep dive into parts unknown. "Blue planet 2" were able to explore the world beneath the ocean's surface like never before. New environments discovered. An under water lake of toxic Brian and sulfur surrounded by flourishing eco system. The cure for cancer could lie here. In this B Rine. What's different about this series. We've really tried to tell unbelievably surprising and new stories from the ocean. The ocean is such a giant, giant part of our planet is really unexplored. They spent four years on the project. We spent unprecedented 6,000 hours under water so never seen before behaviors and on top of that another thousand hours in deep sea submersibles exploring new worlds in the ocean's deep abyss. What was your favorite part. The day we filmed this volcanoe. Went down to see something we weren't sure what we were going to see. It's like I went to another planet that day. And came back to Earth to tell people about this extraordinary world. Filming on every continent in 39 countries across every ocean. To see what a whale sees going to be very exciting. Cameras attached to suction caps placed on these whales following their every move. Whoa! We were very keen to find a way to give the audience the experience what it would be like to ride onto back of a killer whale and we worked hand in hand with aspiring scientists up in Norway. Behind the scenes hungry sharks reminding the crew this is their territory. Humans are foreigners here, battling out against each other. Over a whale carcass and the crew's submarine. . Oh, he's pushing us. Go! And the were bumping at the sub? Yeah. Six gill sharks moved in and got very territorial about this big dinner. But once they realized it's a big yellow electronic thing not a big yellow animal then they carried on just getting on with it. They filmed in complete darkness feasting on glowing plankton. New diving technology and just as importantly a new understanding of ocean life has enabled us to take the audience to new world reveal never seen before behaviors. Producers follow these for six weeks. Fish definitely have personality. Like Percy, cracking open a can plam shell with his tiny mouth. But it was the him bold squid catching producers off guard. We were capturing behaviors we didn't know were going to happen until we got down there. They will hunt wherever they can. These are hungry animals. There's this tug of war between one squid caught another squid because they do eat each other it's this whole canablistic fight going on 900 meters off the coast of C Hile. While there's fascinating creatures under water it also highlights the effects of global warming and pollution and increasing temperatures wreaking havoc on coral reeves home to one quarter of all marine species and in Sarasota bay, dolphins dieing. There's high mortality rate first born calves is higher than what we expect and clearly there's something else going on. An estimated 8 million tons of plastic are dumped into the ocean each year condam nating the waters which could be causing the decline in dolphin populations. After only trolling for 20 minutes this is what we're pulling out. These are tiny but leave toxins in the water. The queen banned plastic straws and bottles, Buckingham palace outlining a new waste plan. We're at a cross roads right now. It's not too late to change the future to make it what we want. It's really important to us people do come away thinking oh, I can do something. There's a native American phrase we don't inherit the Earth from our an Crestors we borrow it from our grandchildren and for me that real Loy strikes a cord. Everybody can do little things, and it adds up and collectively makes a huge difference. For many people the oceans are out of site out of mind. We wanted to make people fall in love with the oceans and recognize we're actually more closely connected to the ocean than we thought possible. For "Nightline" in London. The finale of "Blue planet 2" airs tomorrow on bbc America.
This transcript has been automatically generated and may not be 100% accurate.