Growing nutritious microalgae in onshore aquaculture systems could help increase food production by over 50% and feed a projected 10 billion global population by 2050, according to a new study. Researchers explored how growing algae onshore could close the future gap in society’s nutritional demand while also tackling environmental impacts, but they also highlighted the difficulties that lie ahead for algae farming.

Today’s food production is unsustainable and inefficient. Agriculture is the backbone of food production but with high environmental costs and plenty of greenhouse emissions, there’s a lot to improve. In the ocean, most wild-capture fisheries are already fully exploited or over-exploited, and current marine aquaculture is insufficiently developed and also comes with environmental impacts.

This is where onshore aquaculture systems enter. Researchers from Cornell University argue that growing algae in onshore aquaculture facilities can make a big difference.

A wide array of benefits

The researchers used models to predict yield based on environmental and logistical factors, such as sunlight and topography, and found the coasts of the Global South are the best locations for onshore algae farming sites.

“We have an opportunity to grow food that is highly nutritious, fast-growing, and we can do it in environments where we’re not competing for other uses,” Charles Greene, the study’s senior author, said in a statement. “And because we’re growing it in relatively enclosed and controlled facilities, we don’t have the same kind of environmental impacts.”

Producing food from marine microalgae cultivated in onshore aquaculture facilities comes with many nutritional and environmental advantages when compared to land agriculture, the researchers said. Marine microalgae account for a large, untapped source of high-quality nutritional protein. Many species have a protein content larger than 40% dry mass.

Marine microalgae also provide nutrients that are lacking in vegetarian diets, such as essential amino acids, minerals found in meat and omega-3 fatty acids often found in fish and seafood. Algae grow 10 times faster than traditional crops and are more efficient in the use of nutrients than land agriculture, as they can capture excess nutrients and use them again.

By reducing agriculture’s demand for arable land, the cultivation of marine microalgae can also reduce greenhouse gas emissions and biodiversity loss, the researchers said. They calculated that microalgae could produce a similar amount of protein than soybeans with a cultivation area of 13,700 square kilometers, saving 95 times as much as cropland.

“We just can’t meet our goals with the way we currently produce food and our dependence on terrestrial agriculture,” Greene, a professor of atmospheric sciences, said in a statement. “Algae can actually become the breadbasket for the Global South. In that narrow strip of land, we can produce more than all the protein that the world will need.”

While the potential of microalgae-based aquaculture is significant, the researchers acknowledged there are many challenges ahead to scale it globally – starting with the location. There are many places available in the tropics and subtropics, but cultivation facilities will have to be close enough to sources of seawater to avoid excessive transport costs.

Even more challenging is the requirement for carbon dioxide, which has to be added to the ponds. The costs of supplying this gas, both energetic and financial, must be kept low. For this, carbon dioxide should be produced on-site from non-fossil carbon sources, the researchers said, suggesting the use of direct air capture or bioenergy with carbon capture and storage.

The study was published in the journal Oceanography.