In this final episode, we're looking to the future. The Oceans Treaty which was finally passed last year after decades of negotiations was momentous - but what actually is it? And will it do anything? Senior Policy Advisor Lisa Speer was at the UN HQ in New York when the announcement was made, and joins Hannah to break down what it means, why it's exciting - and what obstacles still stand in the way.

Hannah speaks with Hawaiian community leader Uncle Sol about his island's relationship to the ocean and what the Oceans Treaty means to him; and she also meets Marion Atieno Osieyo, creator and host of the award-winning Black Earth Podcast, for an inspiring chat about the future of conservation.

You can watch the moment the Oceans Treaty announcement was made at the UN Headquarters here: https://www.youtube.com/watch?v=vEEhCjMgFPQ

The podcast is over for now, but we're continuing the conversation on our social media channels. Come and join us @oceanspod on Instagram, TikTok and Twitter. And if this series has inspired you and you want to help in some way, go to https://act.gp/life-underwater.

Everyone knows the oceans are changing. Sea levels are rising, the water's heating up, coral is bleaching. But away from the scary stats, what do the changing oceans actually look like - what impact are they having on us now? Hannah is joined by climate activist Shaama Sandooyea, who explains how climate change is impacting her home nation of Mauritius, and grammy-nominated DJ and environmental toxicologist Jayda G travels to the studio to tell Hannah about her new CNN film, 'Blue Carbon.'

Also - you'll meet Wilson dos Santos, known locally as Safico, one of a community of fishermen from Laguna in southern Brazil who have developed a unique working relationship with the dolphins there. Many thanks to Safico the fisherman, to Ana Cremer Dotto for doing the interview and to João Valle Pereira for the translation.

Follow the show @oceanspod on IG, TikTok & Twitter for bonus content and stunning underwater footage.

If you want to know more about the oceans and how to protect them, come and join us here: https://act.gp/life-under-water.

Hannah's been getting updates from onboard the Arctic Sunrise, one of Greenpeace's research ships, since the beginning of the series - from Panama where it set sail out into the Galápagos Islands marine reserve. We heard as it crossed the equator, and we've learnt about the pioneering research the scientists and volunteers have already done on seamounts in the area. And now, they've finally anchored and we're joining them onboard for an episode all about Galápagos.

You'll meet Sophie Cooke, the expedition lead; Captain Mike, the man behind the wheel; Andrea Vera, an Ecuadorian scientist; and Hannah is lucky enough to be able to catch up with Spanish Actress Alba Flores (from Netflix's Money Heist), who's just got back home after spending a week onboard.

Follow the show @oceanspod on IG, TikTok & Twitter for footage from onboard the Arctic Sunrise, and to see videos of what Alba got up to during her time there.

If you want to know more about the oceans and how to protect them, come and join us here: https://act.gp/life-under-water.

Hollywood has a lot to answer for when it comes to how we view sharks. The Great White, we all know. But sharks have been around since before the dinosaurs, and in that time they've evolved into 538 different species of all different shapes and sizes - and counting. Sharks with glow-in-the-dark armpits, sharks that can fit in your pocket, sharks with spots, sharks with frills. Isla Hodgson joins Hannah in the studio, and she's got some astonishing shark facts up her sleeve.

Also - you'll meet Shaama Sandooyea, a climate activist from Mauritius who staged the world's first ever underwater climate protest.

Follow the show @oceanspod on IG, TikTok & Twitter for bonus content, shark footage, and to see the photo of Shaama's underwater protest which made global headlines.

If you want to know more about the oceans and how to protect them, come and join us here: https://act.gp/life-under-water.

3 billion people rely on the oceans for their livelihoods. But who are they? What are their stories? Hannah's moving away from the ocean's wild animals and meeting its humans instead. She's joined by lifelong fisherman Jerry Percy, and speaks with freediver and ocean advocate Hanli Prinsloo about who the oceans are for.

Also - Frida Bengtsson, a researcher who focuses on fisheries, tells her success story of working with fisheries in the Barents Sea.

Follow the show @oceanspod on IG, TikTok & Twitter for bonus content.

If you want to know more about the oceans and how to protect them, come and join us here: https://act.gp/life-under-water.

They're like aliens from another planet. There are over 300 species and counting, from the size of your fingernail to 10 metres across. They live on the ocean's surface, and in its darkest depths. But how intelligent are they, really? How do they use tools? And what's it like to meet one in the wild? Eminent marine biologist and science communicator Helen Scales joins Hannah in the studio.

Also - meet Gretchen Früh-Green, one of the scientists who discovered the Lost City, which some believe could be the origin of all life on Earth.

Follow us on IG, X and TikTok for bonus content and to see footage of the world's biggest octopus nursery: @oceanspod.

Watch the coconut-carrying octopus here: https://www.youtube.com/watch?v=RUN6c5yWJhQ

If you want to know more about the oceans and how to protect them, come and join us here: https://act.gp/life-under-water.

Did you know that pretty much anything goes in international waters? Past a certain point somewhere beyond the coast, national jurisdiction ends and the Wild West begins. There's no police force for the ocean, so with rampant piracy, smuggling and illegal fishing - who's in charge? Maritime lawyer Richard Caddell joins Hannah in the studio.

Also - we meet Steve Truluck, whose life changed when he started watching whales off the coast of Scotland. His work with Orca Watch brings that joy to other people.

Follow us on IG, X and TikTok for bonus content and to see Steve's footage of killer whales for yourself: @oceanspod.

If you want to know more about the oceans and how to protect them, come and join us here: https://act.gp/life-under-water.

The world's longest mountain range is actually in the middle of the ocean - the mid-Atlantic ridge, at more than 40,000 miles long. But who knows about these mountains? How high are they? Where are they? What lives on them? Hannah is joined by South African actress and TV presenter Amanda Du Pont, who spent two weeks on a Greenpeace ship on a research expedition to Mount Vema in 2019. And she welcomes marine scientist Lucy Woodall back into the studio, who's led expeditions to seamounts all around the world.

Also - there's another update from the Arctic Sunrise en-route to the Galapagos Islands. They've made a stop-off at the ocean mountains near Galapagos.

Follow us on IG, X and TikTok for bonus content and to see original footage of these seamounts for yourself: @oceanspod.

If you want to know more about the oceans and how to protect them, come and join us here: https://act.gp/life-under-water.

Antarctica is one of the harshest environments you can imagine. Winds can reach 200mph and the lowest temperature ever recorded was -89 degrees Celsius. But the monochrome above the waves is matched by the explosion of colour beneath them. The Southern Ocean is home to more than 9000 species, many of which can only be found there. Hannah is joined by scientist Lucy Woodall, who led the first expedition to find Shackleton's ship Endurance, and Antarctic historian John Dudeney.

Also - meet Bhakti Sharma, the youngest person and the first Asian to complete a long-distance swim in all five oceans, the most recent being the Southern Ocean.

Follow us on IG, X and TikTok for bonus content and to see what the Southern Ocean looks like under the waves: @oceanspod.

If you want to know more about the oceans and how to protect them, come and join us here: https://act.gp/life-under-water.

Hannah's asking all the questions you ever wanted to know about whales. Did you know they have culture? She's joined by whale legend Hal Whitehead, whose close encounters with sperm whales and understanding of their culture has completely changed how we view these enormous animals.

Also - we've had an update from the team onboard the Arctic Sunrise, the research ship that's on its way to the Galapagos Islands.

Listen to Roger Payne's groundbreaking whale song recording here: https://www.youtube.com/watch?v=sjkxUA041nM

Listen to his last ever interview here: https://www.youtube.com/watch?v=APtmz_BAWPg

Follow us on IG, X and TikTok for bonus content and whale videos: @oceanspod.

If you want to know more about the oceans and how to protect them, come and join us here: https://act.gp/life-under-water.

What does the bottom of the ocean look like? What animals can exist down there, with no sunlight? And how deep is the ocean, really? Hannah is joined by the submarine pilot John Hocevar.

And you'll meet Quack Pirihi, who explains why they can't be Maōri without the oceans.

Follow us on IG, X and TikTok for bonus content and incredible submarine footage: @oceanspod.

If you want to know more about the oceans and how to protect them, come and join us here: https://act.gp/life-under-water.