How to start a farm under the sea

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Ten years ago, Luca Gamberini’s father, Sergio, decided to pursue what seemed to Luca a crazy project to grow plants under the sea.

The Gamberini family business, Ocean Reef Group, specializing in diving and scuba diving equipment. Agriculture was not part of the picture. But after the idea of ​​planting underwater crops emerged from a dinner between Sergio – who had a passion for gardening, as well as scuba diving – and one of his farmer friends, he decided to go for it. ‘try.

“It was kind of a bet, a funny joke,” says Gamberini. “And my dad was like, ‘hey, you know what, I’m really going to try this.’ And he did. And it worked.

To start, they used small, curved, transparent balloons sunk underwater and filled with air, forming an underwater dome. Initially, the family kept a live plant underwater, then tried to plant a basil seed, which germinated and grew.

But Gamberini says he initially didn’t really see a good reason for it. “I was the number one hater. I opposed it so much,” he says.

He was also opposed to the decision to implement the program off Noli, Italy – the family’s usual vacation spot – as it would mean they would always end up working while on vacation, rather than relaxing.

Luca Gamberini takes care of the plants inside one of the biospheres © Giacomo d’Orlando

But about five years ago, the first time he visited one of the larger, rigid new underwater domes the family had developed, he found himself changing his mind.

“My first minute in one of these great environments, I was like, ‘Ah, okay, that’s pretty cool,'” he says. “These rigid domes look so much better and are incredibly easy to handle. They make a lot more sense and make the technology work. So that’s when I went from being the number one hater and opponent of the project to being the number one fan.

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Today, Nemo’s Garden – the start-up resulting from that dinner conversation – has six domes, each containing around 2,000 liters of air, located at depths between 5 and 11 meters.

To tend to the plants, divers enter the domes from below, their legs still floating in the water as their upper torsos emerge into the air of the biosphere. When the plants are harvested, they are placed in reusable bags or containers, which are sealed and brought to the sea surface for collection.

Harvested plants are brought to the surface

After harvest, the plants are placed in sealed bags or containers, before being brought to the surface © Giacomo d’Orlando

The company has grown a wide variety of plants underwater at the site in Italy, from its brand of basil to other medicinal and culinary herbs, strawberries, lettuce, tomatoes, beans, quinoa and even tobacco (for vaccine purposes, says Gamberini).

Besides the fact that the dome is suitable for crops that require a very humid environment, the limitations are mainly related to size, explains Gamberini. “Due to the geometry of the dome, we cannot grow large objects. We need to grow high-value, high-demand products.

Plants are grown in a nutrient-rich solution (a method known as “hydroponics”), eliminating the need for soil. Meanwhile, the domes provide the water needs of the plants by harvesting fresh water from seawater. The domes are slightly warmer than the outside temperature of the sea, which means that the water from the “bottom » of seawater evaporates inside the dome and condenses on its curved inner surface as fresh water. It then “rains” on the plants.

Basil growing inside a dome in Nemo's Garden

Basil begins to grow from the hydroponic cones in one of the biospheres © Giacomo d’Orlando

This configuration also allows an exchange of CO2 from the ocean inside the dome, adds Gamberini. “We’ve noticed that this environment doesn’t really need to be replenished as much,” he says.

In many ways, the technology is similar to vertical farming systems: it is a carefully monitored, controlled, soilless environment away from the farmer, with live cameras in each module. But in the underwater system, the surrounding sea provides an incredibly stable thermal environment for plants, reducing energy consumption.

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Sunlight reaching the water is also sufficient for plant growth, Gamberini adds, compared to LED lights on vertical farms, which again consume energy. He also says the plants grow faster and have higher levels of essential oils.

There might even be an ecological benefit. A grant-funded survey in 2019 concluded that the structure of Nemo’s garden is likely to have a positive impact on the local ecology of the area. “The amazing thing about the ocean is that every time you put something underwater that acts like an artificial reef, the ecosystem flourishes,” says Gamberini.

Biosphere in Nemo's Garden

The biospheres are located off Noli in Italy, at depths of 5 to 11 meters © Giacomo d’Orlando

So, could this form of farming really be scaled up to compete with conventional farming? Dr George LittleJohnassociate professor of plant and fungal biology at the University of Plymouth, says he thinks niche production is more likely.

He notes that the technology is not yet at a stage where it is a viable means of producing high crop yields and cannot currently provide the high calorie and protein foods needed as the basis of our diets. “This is [also] common to many vertical farming systems,” he adds.

Underwater farming has the advantage of not taking up land space, says Littlejohn, but it also has several pitfalls, including the extra energy inputs needed to supply nutrients to plants, the inconveniences of planting and harvesting, and high maintenance of the whole system.

He also notes that the plants are already well adapted to thrive in the conditions found on landwhere they have access to the full spectrum of light, time of day information via light and temperature signals, as well as nutrients and CO2.

Tree of Life at Nemo's Garden

At the center of Nemo’s garden is the ‘tree of life’, through which cables are routed to the biospheres to power the cameras © Giacomo d’Orlando

However, Littlejohn says developing controlled growth environments in challenging locations, as Nemo’s Garden does, is “essential” for future space exploration. “It may be that the knowledge gained from underwater culture offers benefits by exploring farther than we can yet see,” he says.

Of course, Nemo’s Garden isn’t the only project pushing the boundaries of plant cultivation. Others include the University of Arizona Lunar greenhouse prototypeplant growth experiments currently being conducted on the International Space Station, and NASA’s OMEGA Systemthat floats on the surface of the sea and grows algae.

Despite the spatial aspect of Nemo’s Garden pods, Gamberini says that imagining the technology being used on another planet such as Mars is “way above [his] salary level”.

There could be application in space travel, he says. The intense flavors of crops grown in high-pressure underwater habitats could be useful in bringing flavor to foods eaten in low-pressure environments – like in space – where our taste buds can go haywire.

The Garden of Nemo team

The team celebrates a final harvest on the beach © Giacomo d’Orlando

But the potential impacts of underwater farming here on Earth are perhaps more useful for the foreseeable future. Gamberini says he sees underwater farms as an option, especially for coastal communities outside the western world, like the Maldives, which lack arable land for farming but have many experienced divers. “I think it’s a really viable option to put next to all the other technology that’s coming,” says Gamberini.

For now, the company is considering its next step in scaling, having been selected for the acceleration program of Neom, Saudi Arabia’s controversial megaproject to build a futuristic smart city from the ground up. in the desert. This fall, Nemo’s Garden will present business and feasibility studies to build 30 biospheres for the project, which could produce 3.1 tonnes of basil per year with current technology.

Gamberini hopes that next year they could set up a project in Neom to be the world’s first real underwater farm.

By 2030, he would like the company to employ hundreds of people and set up underwater domes around the world. “No one has done this before,” he says. “We can only learn by experience.”

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