A new documentary brings previously unseen life on the Pacific abyssal plain into view and underscores the danger industrial mining poses to those ecosystems. How Deep Is Your Love follows a Natural History Museum research team and an underwater robot called Isis on a 12-day voyage to the Clarion Clipperton Zone, a biodiversity-rich stretch of ocean between Hawaii and Mexico that mining companies prize for its mineral nodules.
The film records a 3-mile, 5km descent that takes Isis about five hours, and captures creatures never before filmed at those depths, including an unidentified neon-pink sea cucumber nicknamed Barbie Pig. Other odd forms win nicknames such as Headless Chicken Monster and Psychedelic Elvis Worm, as scientists watch the live feed from a camera 5,000 metres below the surface and catalogue species in real time.
Mortimer, the director, frames the film as an ode to taxonomists and the painstaking work of naming life from the deep. Even after DNA is collected, she says, it can take up to 14 years to formally name a species. The point is sharpened by a startling statistic the film presents: humans have observed only 0.001% of the deep seafloor, commonly defined as depths below 500 metres where sunlight disappears.
How Deep Is Your Love does not fit neatly into activist polemic or traditional nature documentary. Mortimer’s narration is dreamlike and philosophical, and the film intercuts life at sea with scenes at the International Seabed Authority in Jamaica, where talks earlier this year ended without a regulatory framework and left gaps in data needed to set environmental thresholds for mining.
The film stages a moral dilemma plainly: studying a creature often requires bringing it to the surface, a trip many abyssal animals cannot survive. Mortimer says she wants people to connect with and cherish the deep: "I want people to fall in love with the deep sea, I want people to connect with it." The production credits list Luna Films and Ngauruhoe Films, presented by Sandbox and co-produced with science adviser Muriel Rabone.
How Deep Is Your Love premiered at the Margaret Mead Film Festival in May 2025 and opens in selected UK cinemas on 2 October. The film closes on a plea for empathy, suggesting that public attention could be decisive as scientific teams race to identify species before mining developments make that impossible.
