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Cultivating Marine Biomass as an Ocean Solution
Dr. Anthony T. Jones
The U.S. Department of Energy (DOE) forecasts that by 2050 the energy portfolio will have a large biofuel component. Current biofuels from subsidized corn for ethanol production is unsustainable; besides, corn has higher value as a food and animal feed supply. Terrestrial sources of biomass compete for arable land, freshwater and fertilizer with conventional agricultural demands. DOE recognizes the extensive underutilized space available in the U.S. Exclusive Economic Zone (EEZ), which is one of the world’s largest and exceeds the terrestrial space of the U.S. In the EEZ, there is plenty of water and space for marine biomass cultivation, plus a reservoir of nutrients below the thermocline.

This year, DOE’s Advanced Research Projects Agency (ARPA-E) launched the research program Macroalgae Research Inspiring Novel Energy Resources (MARINER) to fund projects to advance disruptive cultivation and harvesting techniques to enable profitable and energy-efficient production of marine biomass with seaweeds or macroalgae in the oceans. Traditionally, seaweed cultivation is labor intensive in sheltered embayments, primarily in Asia, not in open ocean or offshore environments. The challenge is to develop industrial-size economies of scale to supply biofuels or chemicals at costs below comparative terrestrial biomass production.

The four areas of interest of ARPA-E MARINER are: the design and field testing of integrated cultivation and harvest systems; models to support operations; sensors to monitor growth, composition and nutrient concentration; and development of advanced breeding tools. The program’s goal is to meet 10 percent of domestic energy need from biofuels derived from seaweed in three decades. That ambition represents 200 million dry tons annually. Costs targets are under $80 per dry ton.

Mark Capron, a wastewater treatment engineer from Ventura, California, and his team at Ocean Foresters has a vision of creating massive seaweed-based ecosystems that produce biofuels for energy, expand food supply and sequester carbon dioxide. This vision won in the Most Innovative Business Model and Technology category at the 2017 American Society of Civil Engineers’ Grand Challenge to adopt innovation to reduce infrastructure life cycle costs by 50 percent by 2025.

Seaweed plantations are envisioned to total the size of Nebraska in the Gulf of Mexico, reusing nutrients from the Mississippi River and wastewater treatment plants, significantly reducing wastewater treatment costs, eliminating dead zones and restoring the health of the ocean. This is based on seaweed’s conversion of carbon via photosynthesis that yields production of food and biofuels. Revenue of $50 billion per year in seaweed for biofuel, $50 billion per year in fish and shellfish (25 times the current U.S. seafood consumption) and savings in the hundreds of millions for disposal costs at wastewater treatment facilities are projected. Benefits also include restored biodiversity and rectifying dead zones by utilizing a greater portion of the nutrients in agricultural runoff. Offshore oil and gas structures in the Gulf of Mexico can serve as existing assets to construct and build out massive seaweed farms. Newer technologies related to automation of tasks associated with the cultivation, harvesting and processing of seaweed are in development.

An important aspect of the growth of ocean forests is the role macroalgae have in pulling carbon dioxide from the atmosphere. Macroalgae cover 3.5 million sq. km in coastal areas and have net primary production on the order of 1,520 terragrams of carbon per year, of which 173 terragrams per year are sequestered. Eighty-eight percent of the sequestered carbon is transported and sequestered in the deep sea.

The European Union has identified the need for development of seaweed farming as a means of utilizing the northern European marine environment and providing good jobs for coastal villages. The EU funded a program to examine advanced textiles for open-sea cultivation of seaweed, specifically looking at 2D seaweed cultivation substrates. The result was a spin-off technology company, AT˜SEA Technologies in Belgium. AT˜SEA, with support from textile giant Sioen Industries, has developed sheets of advanced textile at 2 by 10 m. The sheets can be seeded with algal spores and set on buoy lines for a growth season of four to six months. A consortium of companies with expertise in spinning, weaving and applying coatings to textiles, cables for anchoring, and chemical dispersant of fertilizer via microcapsules joined the effort. The technology won the New Materials category at Techtextil 2015. AT˜SEA now offers turnkey seaweed farm systems to supply food and food additives and biomaterials for cosmetic and pharmaceutical markets, and will eventually produce biomass for biofuels.

This is the first attempt at offering a solution for industrial-scale cultivation of seaweed for the European Market. Labor costs need to be considered in designing cost-effective and economically feasible operations. If the sheets can be wound on rollers with the floatation incorporated into the sheets, then the cultivation sheets could be deployed by aerial or marine drones and harvested remotely by robots.

Such innovation bodes well for seaweed as an ocean solution. We should stay tuned for the role of seaweed in the coming years in improving coastal water health and providing local jobs.

The oceans are important for the health and security of any water-bound country. As VAdm. Paul Gaffney II (U.S. Navy, retired) wrote in an editorial in USA Today in June, the new presidential administration must not “forget the oceans” as it builds a policy framework for the nation.

Oceanographer Dr. Anthony T. Jones uses his deep knowledge of ocean processes to solve ocean challenges. Jones founded Intake Works LLC in Sacramento, California, to deliver clear, sterile saltwater to desalination facilities while “leaving the fish in the sea.” The company comprises oceanographers, marine and coastal geologists, and experts in horizontal directional drilling and marine construction.


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