SeaweedPaddock Pelagic Sargassum Ranching
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 Southern Mississippi (USM) will lead a MARINER Category 1 project to design and develop a semi-autonomous enclosure, called a seaweed paddock, to contain and grow mats of free-floating Sargassum, a brown seaweed species native to the eastern Atlantic and the Gulf of Mexico. One of the major cost drivers for production of macroalgae is the expense of the farming equipment, particularly anchors used to hold the farms in place in a particular spot in the ocean. Unlike most kelps, Sargassum does not require anchoring to a fixed structure, but rather will grow as a floating mat at the ocean surface. By leveraging this feature, the USM team will reduce the equipment and cost required to produce this seaweed. The system's Sargassum mats are enclosed by a floating sea fence that can be dynamically positioned by wave powered drones, operated remotely onshore by a single person to ensure maximum exposure to nutrients while avoiding ships and storms. Ocean health is improved in these areas where the collection of mats use excess nutrients in ocean deadzones, reducing ocean acidification while increasing dissolved oxygen levels from photosynthesis. Over the course of a yearlong mission that never returns to shore, the system could grow over a hundred thousand tons starting from a single ton of seaweed.
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.