The ocean is the answer to future food security but we’re not using it: scientists

The vast majority of coastal countries on Earth are missing out on a valuable resource to ensure future food security, according to newly published research.

Published in the journal Nature Ecology and Evolution, the research has found that the world’s oceans contain numerous “hot spots” for marine aquaculture, or ocean-based fish farms, which could produce 15 billion tonnes of fish every year: over 100 times current seafood consumption globally.

“There are only a couple of countries that are producing the vast majority of what’s being produced right now in the oceans,” said lead author Rebecca Gentry, from UC Santa Barbara’s Bren School of Environmental Science and Management. “We show that aquaculture could actually be spread a lot more across the world, and every coastal country has this opportunity.”

However, an unwillingness by governments to seriously explore aquaculture could seriously jeopardise this.

“There is a lot of space that is suitable for aquaculture, and that is not what’s going to limit its development,” said Gentry. “It’s going to be other things such as governance and economics.”

A fish farm in Dugi Otok, Croatia

At present, many countries choose to import much of their seafood, despite significant potential to meet their own needs.

The US, for example, imports over 90% of its fish, resulting in a trade deficit for seafood alone that tops $13bn. However, it could produce its entire domestic supply using just 0.01% of its ocean territory.

Worldwide, the story is similar: aquaculture could match the entire seafood production of every wild-caught fishery using a combined area the size of Lake Michigan: less than 1% of the total ocean surface.

And with food security under increasing threat, it is only a matter of time before countries take aquaculture seriously.

“Marine aquaculture provides a means and an opportunity to support both human livelihoods and economic growth, in addition to providing food security,” said co-author Ben Halpern, executive director of the National Center for Ecological Analysis and Synthesis (NCEAS). “It’s not a question of if aquaculture will be part of future food production but, instead, where and when. Our results help guide that trajectory.”

Cages used in marine aquaculture

With such potential, it is no surprise that aquaculture is already on the increase.

“Aquaculture is expected to increase by 39% in the next decade,” said study co-author Halley Froehlich, a postdoctoral researcher at NCEAS. “Not only is this growth rate fast, but the amount of biomass aquaculture produces has already surpassed wild seafood catches and beef production.”

However, if aquaculture is going to be a core part of future food production, it needs to be managed properly, something that hasn’t always happened in the past. In the 90s, the poor management of shrimp farming in Thailand led to a boom and bust that left vast coastal areas barren.

“Like any food system, aquaculture can be done poorly; we’ve seen it,” said Froehlich. “This is really an opportunity to shape the future of food for the betterment of people and the environment.”

Bionic leaf creates its own fertiliser to fuel new ‘green revolution’

Researchers have invented a new bionic leaf that uses bacteria, sunlight, water and air to make fertilizer in the very soil where crops are grown. It is hoped that the leaf will be able to serve a vital role in kickstarting a new ‘green revolution’ like that of the mid-20th century.

The first green revolution saw a massive increase in the use of fertiliser on new wheat and rice varieties, helping to double agricultural production. Though far from a perfect solution – the  increased use resulted in serious environmental damage – the United Nations (UN) Food and Agriculture Organization have said that the move quite possibly saved millions of lives.

However, while it served at the time, a new green revolution is required. With the world’s population expected to grow by another 2 billion by 2050, a solution to boost production without having to clear masses more land for farming is urgently required.

A multi-pronged approach will be necessary, but the bionic leaf could play a vital role.

“When you have a large centralised process and a massive infrastructure, you can easily make and deliver fertiliser,” said Dr Daniel Nocera.

“But if I said that now you’ve got to do it in a village in India onsite with dirty water — forget it. Poorer countries in the emerging world don’t always have the resources to do this. We should be thinking of a distributed system because that’s where it’s really needed.”

Nocera is known for his previous work on artificial leaves turning sunlight into liquid fuel, which we reported on here, and is now looking to turn that expertise towards the creation of fertiliser.

Previous iterations of the leaf, when exposed to sunlight, paired a water-splitting catalyst with the bacteria Ralstonia eutropha, which consumes hydrogen and takes carbon dioxide out of the air to make liquid fuel.

Radishes grown with the self-fertilising bionic leaf, right, alongside those grown with conventional methods. Image courtesy of Nocera lab, Harvard University

Last June, Nocera’s bionic leaf even reached the point of providing biomass and liquid fuel yields that greatly exceeded those from natural photosynthesis. Now, by using Xanthobacter bacteria, the leaf can fix hydrogen from itself and carbon dioxide from the atmosphere to make a bioplastic that the bacteria store inside themselves as fuel.

“I can then put the bug in the soil because it has already used the sunlight to make the bioplastic,” Nocera explained. “Then the bug pulls nitrogen from the air and uses the bioplastic, which is basically stored hydrogen, to drive the fixation cycle to make ammonia for fertilising crops.”

The research team have already tested the ammonia production of the system but have found real proof in growing radishes. Using the system to grow five crop cycles, they found that the vegetables receiving the bionic-leaf-derived fertilizer weigh 150 percent more than the control crops.

With this success behind them, Nocera has said that the next step is boosting throughput to get to the point where farmers in locations such as India or sub-Saharan Africa can produce their own fertiliser.