Growing in the ocean: Developing seaweed farming pegged as sustainable alternative to land-based agriculture

30 Jan 2023 --- Farming more seaweed could unlock the potential to feed the world’s ballooning population, expand fuel production and sustainably feed animals. A new study has revealed that expanding seaweed production globally with significant-sized ocean farms could prop up food security, provide nutritious ingredients, address biodiversity losses and, crucially, help move away from land-based agriculture.

Seaweed’s potential is currently untapped as there are many more species that have yet to be studied from a commercial perspective and specialized breeding programs could see seaweed become much more refined in the same way that key crops like wheat and corn have been developed by decades and decades of breeding.

Noting how seaweed farming, currently a nascent industry, has massive potential as an alternative to growing crops on the land, researchers from the University of Auckland, Australia, pinpoint seaweed farming as an answer to some of the biggest challenges facing global food systems today. 

Their study identifies parts of the ocean suitable for seaweed cultivation. They claim these ocean areas could reduce the impact of land agriculture and constitute 10% of the human diet. 

“Our study found that expanding seaweed farming could help reduce demand for terrestrial crops and reduce global agricultural greenhouse gas emissions (GHG) by up to 2.6 billion tons of CO2-equivalent per year,” says Ph.D. Candidate Scott Spillias from UQ’s School of Earth and Environmental Science. 

Versatile seaweed brimming with potential 
Seaweed has great commercial and environmental potential as a nutritious food and a building block for commercial products, including animal feed, plastics, fibers, diesel and ethanol, the study highlights. 

Researchers mapped the potential of farming more of the 34 commercially important seaweed species using the Global Biosphere Management Model.

They estimated the environmental benefits of various scenarios based on land-use changes, GHG emissions, water and fertilizer use, and projected changes in species presence by 2050.

There are millions of available hectares of ocean where seaweed farming could be developed.“In one scenario where we substituted 10% of human diets globally with seaweed products, the development of 110 million hectares of land for farming could be prevented,” Spillias explains.

“We also identified millions of available hectares of ocean within global exclusive economic zones (EEZs), where farming could be developed.”

An EEZ is an area of the sea in which a sovereign state has special rights regarding the exploration and use of marine resources, including energy production from water and wind.

Where to grow?
The researchers found that the largest share of suitable ocean water was in the Indonesian EEZ, where up to 114 million hectares are estimated to be suitable for seaweed farming.

“The Australian EEZ also shows great potential and species diversity, with at least 22 commercially viable species and an estimated 75 million hectares of the ocean being suitable,”  Spillias continues, pointing out that there are many native species of seaweed in waters that had not yet been studied from a commercial production perspective.

“The way I like to look at this is to think about ancestral versions of everyday crops – like corn and wheat – which were uninspiring, weedy things,” he says.

“Through thousands of years of breeding, we have developed the staple crops that underpin modern societies and seaweed could very well hold similar potential in the future.”

The researchers stress that the seaweed solution would have to be carried out carefully to avoid displacing problems from the land to the ocean.

Seaweed: Food for humans and animals
In many applications, seaweed is making waves in food for people and animals. 

IFF has developed a red seaweed flour to stabilize plant-based milk, while Cargill has developed its first seaweed powder WavePure ADG 8250, a marine ingredient to accentuate smooth and creamy textures in dairy while offering gelling and thickening properties.Researchers mapped the potential of farming more of the 34 commercially important seaweed species.

Another example of seaweed innovation comes from food biotech company NewFish which ferments New Zealand microalgae and underused seafood to create meat-free charcuterie.

The company is exploring the unique nature of New Zealand pāua (abalone), microalgae and macroalgae (seaweed).

The seaweed category has grown more than 63% in the last five years, according to reports by industry players, as consumer awareness about seaweed’s mitigation of climate change and health benefits continues to grow.

Awareness surrounding the nutritional benefits of seaweed – such as its high content of iodine, calcium, magnesium, iron, vitamins and antioxidants – has led to innovative product development, including novel functional beverages and desserts.

Bill Gates is backing Rumin8, a start-up targeting methane emissions in agriculture through its synthetically replicated red seaweed. 

Launched last July, the EU-funded SeaMark project also awards cash injections for sustainable seaweed ingredients. 

The new study is published in Nature Sustainability.

By Gaynor Selby