The Blue Fields Project
A Demonstration of Offshore Deep-Cycling Limu (Seaweed) Farming in Hawaiʻi Waters
Project Overview:
The Ocean Era MARINER team has launched an offshore seaweed cultivation array, located 8 nautical miles off Makalawena Beach, Hawaiʻi, as the final phase of a five-year Department of Energy–supported initiative. Anchored at a depth of 400 meters, this demonstration project tests whether Hawaiʻi’s deep ocean environment can support native limu (seaweed, or macroalgae farming).
Why Seaweed?
Fast-growing native seaweeds like Caulerpa (green) and Halymenia (red) are promising sources of delicious foods, and biomass for other products and processes:
No fresh water needed.
No Fertilizers Needed: Uses deep-sea nutrients.
Creates habitat and increases biodiversity and productivity.
Potential Products: Edible limu, soil additives, cosmetics ingredients, and biomaterials.
How does the system work?
Our submersible ring mimics natural nutrient upwelling, but without the upwelling:
The rig is lowered weekly to a depth of 200 meters to reach an optimal nutrient saturation depth, allowing the limu to absorb essential minerals. It is then raised back to the surface, where the limu performs photosynthesis using sunlight. This process ensures the plants receive all the nutrients and energy they need to thrive.
During the cycle, natural ocean currents gently stimulate the limu, which promotes more vigorous and healthy growth. By combining this natural motion with a precise weekly cycle, we create an efficient and self-sustaining environment for offshore macroalgae farming.
Acknowledging Our Impact?
While we aim to reduce dependency on land-based resources, this project does require support systems that use conventional energy:
Regular fuel-powered boat trips for monitoring and maintenance.
Use of scuba tanks filled on land via electrical compressor systems.
We’re not presenting this as a zero-emissions operation — instead, this pilot strikes a balance between practicality and progress, helping us assess the real-world scalability and trade-offs of offshore macroalgae farming.
Early Results & Next Steps
Halymenia has shown up to 8% daily growth in land-based flume tank simulations
Caulerpa trials indicate fast, reliable growth in nutrient-enhanced conditions.
In this offshore trial, we’ll monitor survival, growth, and ecological impact.
This project is a mock commercial trial, designed to test technologies and inform future designs that could one day scale with cleaner energy and more efficient logistics.
Why it matters?
The Blue Fields project demonstrates a first-of-its-kind, site-specific model for regenerative ocean farming in Hawaiʻi. With continued refinement, this approach could:
Support Hawaiʻi’s food security and ocean health.
Help reduce fertilizer use and restore coastal ecosystems.
Contribute to better nutrition for Hawai`i’s consumers. We’re proud to share this final phase with our stakeholders — not as a finished solution, but as a tangible, tested step toward one.