The Source of Life dome displayed at Expo 2025 Osaka-Kansai demonstrates a compact, closed-loop approach to growing fresh food in tight urban spaces, blending aquaculture and layered hydroponics inside a 21-foot, greenhouse-inspired structure designed to recycle water and nutrients efficiently.
The dome is built around four water zones that host marine, brackish and freshwater species, with waste from those animals feeding plants above. Microbial processes turn ammonia into nitrates that plants use, creating a nutrient cycle that mimics natural wetlands. That biological engine lets the system run with minimal external chemical inputs.
Stacked above the tanks are four hydroponic tiers arranged by salt tolerance, from sea-adapted greens to delicate herbs and leafy vegetables. Salt-tolerant greens sit over the seawater tank while tomatoes and semi-salt-tolerant crops occupy the brackish level. Herbs, lettuce and other freshwater-friendly plants grow above species like sturgeon, and edible flowers take the topmost layer where sunlight is strongest.
Transparent ETFE panels cover the dome and admit broad, soft light while helping stabilize internal temperatures and humidity. A set of pumps circulates nutrient-laden water upward and returns treated water to each tank, so the system retains nearly all of its resources. The configuration deliberately reduces waste by keeping water and nutrients in continuous motion.
The compact footprint makes rooftop or small-plot installations realistic, turning underused urban spaces into productive food sites. Instead of relying on distant monoculture farms, a city could distribute dozens of these domes across roofs and community sites to shorten supply chains. Residents would gain direct sightlines to where their greens and herbs originate, increasing transparency and food literacy.
Designers from Osaka Metropolitan University and the Tokyo University of Marine Science and Technology modeled the dome on natural recycling systems rather than on conventional farm layouts. By copying wetland dynamics, the setup balances biodiversity with productivity and buffers against environmental swings. That biological variety helps stabilize yields and reduces dependence on soil and predictable weather patterns.
Scaling this model could change resilience calculations for urban food systems, especially when transportation or large farms are disrupted. A distributed network of closed-loop domes would keep some food flowing into neighborhoods even during storms or supply interruptions. For people with balconies, small yards or no ground at all, a dome offers a practical path to locally produced, fresh ingredients.
Beyond resilience, the dome highlights how integrated aquaculture and hydroponics can stretch scarce urban resources like water and rooftop area. Each drop is reused, and the stacked design multiplies production per square foot compared with horizontal beds. It also opens room for community programs at schools, senior centers and housing complexes to host hands-on learning about ecology and food systems.
The prototype shown at Expo 2025 points to practical questions rather than polished answers: How will maintenance be handled at scale, what are realistic energy and labor costs, and how do we ensure biosecurity in dense urban settings? Those operational details will determine whether domes stay curiosities or become commonplace infrastructure. Still, the concept demonstrates a clear route for putting fresh, traceable food closer to where people live.
