Dir: Eleanor Mortimer | UK Doc 100’
The ocean may cover more than two-thirds of the Earth’s surface, yet its deepest regions remain among the least familiar places on our planet.
In How Deep Is Your Love?, director Eleanor Mortimer takes us into this remote, largely invisible world, where life has adapted to conditions that seem almost beyond imagination. What begins as an expedition into the unknown gradually becomes a story about our own future: how much can we take from the natural world before we undermine the very systems on which our survival depends?
The film follows a team of marine biologists on a scientific expedition to the Clarion-Clipperton Zone in the Pacific, a vast stretch of seabed rich in minerals and home to an astonishing variety of little-known organisms. Their task is to investigate and catalogue these creatures, some of which may be entirely new to science. The narrative is driven by the researchers’ curiosity and the unpredictable discoveries that emerge from their work, lending the film a sense of adventure without losing sight of its larger implications.
Mortimer’s visual approach makes the most of this strange underwater environment. Against the darkness of the deep, unfamiliar creatures appear in unexpected shapes, colours and textures, their delicate bodies seemingly designed for another universe. There is something almost otherworldly about these images, which challenge our assumptions about where life can flourish and what it can look like. The contrast between the scientists’ painstaking observations and the extraordinary organisms they encounter gives the film both intimacy and visual excitement.
Yet the expedition carries a growing sense of urgency. The mineral deposits beneath the seabed have attracted commercial interest, raising questions about whether deep-sea mining should proceed when so little is known about the ecosystems it could disturb. The film’s scientific investigations thus acquire a wider significance: discovery is no longer simply a matter of expanding knowledge, but of deciding how that knowledge should inform our actions.
This is where How Deep Is Your Love? becomes particularly thought-provoking. Human progress has too often been measured in terms of what can be extracted, developed or exploited, with the consequences for the natural world considered only afterwards. The deep ocean presents an opportunity to reconsider that approach before irreversible damage is done. Its unfamiliar inhabitants may seem remote from our everyday concerns, but their existence is a reminder of how much remains to be understood about the planet we inhabit.
Mortimer does not need to resort to apocalyptic predictions to make her point. The film’s combination of scientific enquiry, unexpected beauty and the looming prospect of industrial intervention is sufficient to raise uncomfortable questions about humanity’s priorities. Its underlying message is that survival in the future will require more than technological ingenuity or access to new resources: it will demand restraint, curiosity and a willingness to recognise the limits of our knowledge.
With its soothing narration How Deep Is Your Love? offers a compelling reminder that the unknown is not necessarily an empty space waiting to be exploited. It may instead be a world of extraordinary complexity, whose value we have barely begun to appreciate. Before we disturb it, perhaps we should first understand it.
IN CINEMAS from 2 October 2026