Interior architecture creates new natures in the UNDERWATER FACTORY. Here, ‘nature' is a co-produced relationship of organisms and environments. I focus on a critical species in the Anthropocene: the disappearing kelp forests of the Southern Ocean. Kelp is a major marine habitat-forming species but 90% have already been lost. This factory operates within the sea with mechanisms, humans and other species interacting for mutual survival. By developing interventions that nurture the forest, train others in non-invasive kelp harvesting, experiment with bio-materials, and increase awareness of 'working-with' other species, I create new possibilities for designing our industrial spaces of the future.