Scalable Coastal and Offshore Macroalgal Farming
Marine macroalgae, also referred to as seaweeds or kelp, are a group of exceptionally diverse aquatic plants. Macroalgae can be found along nearly all coastlines around the globe and in some cases also in the open ocean. They have traditionally been used for food and feed, as well as fertilizer. In 2016, the world produced approximately 26 million wet metric tons of seaweed, primarily through highly labor-intensive farming techniques. While macroalgae production has increased six-fold over the past quarter-century, the current state of macroalgae “mariculture” is not capable of achieving the scale, efficiency and production costs necessary to support a seaweed-to-fuels industry. Dramatically increasing productivity will require significant advancements in the domestication of macroalgae and new farming technologies. To accelerate the development of critical tools and technologies, the MARINER program is supporting projects in five areas: 1) Integrated Cultivation & Harvest System Design, 2) Critical Enabling Components, 3) Computational Modeling, 4) Monitoring Tools, and 5) Breeding & Genomic Tools.
Project Innovation + Advantages:
The University of Alaska Fairbanks will lead a MARINER Category 1 project to design and develop replicable model farms capable of cost-effective production of sugar kelp, a type of macroalgae suitable for large-scale cultivation is U.S. ocean waters. Much of the cost of kelp farms is related to expensive anchor components, and the laborious process of installing and planting individual longlines between opposing anchors. Another 20% of the cost is ascribed to the harvest process and transport. The team plans innovations to reduce both equipment and operating costs. First, the team will implement a two-point mooring system, anchoring the longline superstructure to only two opposite anchors. Two-point moorings will reduce project costs, and they will allow the superstructure to be more easily lowered to avoid damaging storms or to take advantage of cooler water temperatures or additional nutrients available at lower depths. The reduced complexity of their proposed design also allows the deployment of an entire 1 hectare farm in less than a day. The team seeks to integrate the entire farming process, including seed production, outplanting, grow-out, harvest, and re-seeding. A particular emphasis will be on the development of cost-effective harvesting methods based on technologies applied in the commercial fishing industry. Test deployments for the integrated system are planned for locations in Alaska and New England. Additionally, team members working in Alaska will investigate the potential for “ultra” long-line systems of greater than 1 km in length. These systems may be exceptionally well suited for deployment in the protected waters of the expansive Alaska coastline.
If successful, MARINER projects strive to develop the tools needed to allow the United States to become a world leader in marine biomass production for multiple important applications, including the production of biofuels.
Production of biofuels and bioenergy from domestically produced marine biomass could ensure that the U.S. has at its disposal a scalable, domestic source of low-carbon energy supplies.
Growing large amounts of macroalgae would not compete with land-based food crops, requires no fresh water and can be grown without the addition of energy-intensive, synthetic nitrogen fertilizer. Large-scale macroalgae cultivation may help reduce the negative effects of nutrient overload and ocean acidification in many coastal ocean regions.
A domestic macroalgae industry would not only create a valuable new source of domestic energy, but also create significant new economic and employment opportunities in many waterfront communities along the U.S. coasts from Maine to the Gulf of Mexico, Alaska, and the Pacific Islands.