Scarcity of resources increase while linear nutrient flows from land to sea contribute to marine eutrophication, and consequently loss of biodiversity. It is imperative to change the linear nutrient flows from land to sea into circular nutrient flows in order to conserve bioavailable nitrogen and phosphorus in the technosphere. Land-based fish production in recirculated aquaculture systems (RAS) provide opportunities to capture and utilise emissions of nutrients and CO2 for cultivation of macroalgae in Integrated Multitrophic RAS (IMRAS). Hereby emissions are turned into revenue streams generating a double crop production, while alleviating the biosphere from negative impacts of nutrient and CO2 emissions.
Ulva – opportunistic green macroalgae, grows explosively under favourable conditions, generates high biomass production, and are attractive for European and global food and feed markets. Pure Algae has found a unique method and developed a technology for increasing the yield and bioremediation capacity of Ulva (figure 1) and keep this process stable over a long period of time (figure 2), while monitoring the quality of the seaweed as a result herof (figure 3)
Results prove that Ulva biomass can be produced in high output and high quality when integrating a vertical seaweed cultivation system into the RAS industry. This will be further developed and scaled up in the ValueFarm project.