Review: ‘How Deep is Your Love’ Doc Reminds Us to Save Our Oceans
by Alex Billington
March 28, 2025
There’s an ongoing battle to save a part of this planet from destructive mining that most people don’t know about. Not only do they not know about the battle, they also don’t even know much about the area greedy corporations want to mine. This new documentary titled How Deep is Your Love shines a light on both of these aspects. The film just premiered at the CPH:DOX Film Festival in Copenhagen this month, playing in their Science section, after first premiering at the True/False Film Fest in the US earlier this year. How Deep is Your Love is yet another urgent, meaningful, entirely captivating modern documentary film about environmental issues that most people need to be informed of right now. We cannot wait on this issue. We cannot clean things up and replant and reseed this part of the world once it’s destroyed – even if it’s far away from us. The doc focuses on deep sea mining of underwater rocks called manganese nodules – containing precious minerals which manufacturing industries are desperate to get their hands on. But which creatures and deep sea animals live down there? That’s what the scientists in this film are sent to find out and study…
How Deep is Your Love is written and directed and filmed by British doc filmmaker Eleanor Mortimer, presenting her first feature documentary after making many other shorts previously. Mortimer takes a much more calm and cool approach to introducing us to this worrisome problem with deep sea mining. The film features Mortimer’s voice throughout as a narrator, not only discussing what is happening with all of these scientists we’re watching, but also adding poetic storytelling to the footage. The other doc film about deep sea mining is narrated by Jason Momoa, and her voice is as opposite from his as any could be – an entirely different approach to voicing the same concerns. Mortimer boards a big boat which has been funded by the corporations as part of a requirement to fund research & science before they begin mining. It’s packed with a team of scientists and mechanics, who send robotic vessels down to the bottom of the Pacific Ocean with cameras and collection buckets. Their goal is to discover & classify deep sea creatures down there in order to hopefully indicate that this is a protected area of the planet that we cannot mine or risk killing all of these animals. All the while the threat of the mining industry looms over them – will they start mining anyway…?
Mortimer’s doc How Deep is Your Love is the second major documentary I’ve watched in the last few years about nodule mining. The other one is called Deep Rising – it first premiered at the 2023 Sundance Film Festival a few years ago (read my review). I’m glad there are already two docs about deep sea mining, but I’ll admit it’s hard to get anyone to watch or care about them. On one hand, all that matters is that these films bring attention to ocean nodule mining in hopes that more people speak out and do what they can to stop it before they destroy the ocean(s). On the other hand, these films also matter because they’re both trying to being cinematically intriguing films about our beautiful planet and the people trying to protect & save our planet. Mortimer’s doc is much more tender, much more poetic and charming, with a woman’s touch & gaze in the filmmaking & storytelling. She’s not trying to yell that: we need to do something! She is showing us how scientists are already trying to do something, but is it enough? Can it make a real difference? Now that we’re informed, everyone living on land needs to do more to stop deep sea mining and keep the oceans safe.
The best part of Mortimer’s doc is all the footage of the sea creatures this research vessel encounters. There are countless organisms and animals and unique species that we’ve never seen living down there. They’re so cute! And so ancient! Don’t touch them! Don’t destroy their environment like we already have with so much of the land on Earth. The Clarion–Clipperton zone in the Pacific where they want to mine is around 2.5–3.7 miles (4–6 km) deep, and it’s hard to get down there. Even the submersible robot they send breaks down a few times. They capture rare footage of these animals then try to collect them for scientific sampling – only once a species has been identified can it be used to stop the mining. The film’s pacing is a bit uneven, and the lightness of her voice does lack urgency discussing this destructive situation. However, I was still moved by the film anyway, enough so that I must write about it as well and continue to talk about deep sea mining, too. One of the most eye-opening moments is when Greenpeace activists perform an anti-mining stunt by latching onto their boat, unaware it’s full of scientists also trying to stop mining. Which makes the scientists and viewers stop and think – are we doing what is right to prevent deep sea mining? What else can we do?
Alex’s CPH:DOX Rating: 7.5 out of 10
Follow Alex on Twitter – @firstshowing / Or Letterboxd – @firstshowing
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