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Future trend: Under-water farming

"Farming" among fish and algae

To grow fruit, vegetables, and herbs sustainably under water over the long term; this is the plan being pursued by the initiators of "Nemo's Garden". Plants have been thriving in this new system for cultivation in large balloon-like structures, so called biospheres, which are anchored to the sea bed at a depth of up to ten metres. The process is underpinned by an ingenious supply system and a revolutionary vision.

Nowadays, industrial agriculture often consists of large scale monocultures. Constant technological and chemical improvements enable faster plant breeding. A study by the UN Environment Programme's International Resource Panel in 2010 found that agriculture is one of the most important reasons for the ecological imbalance. Now imagine mass agriculture without pesticides and fertilisers; agriculture that does not require large quantities of freshwater. Sergio Gamberini, President of the Ocean Reef Group which is also responsible for the project "Nemo's Garden", is pursuing precisely this vision.

"Our aim is to create an under-water farming system where fruit and vegetables grow similar to those grown in a traditional greenhouse, but in an ecologically sustainable manner. We want to support agricultural development in areas where it is limited by geographic and environmental factors," says Gamberini. As such the Ocean Reef Group uses its expertise and technology from diving to create farming under water that is not dependent on climate. This will help to counteract water scarcity, droughts, desertification, growing world population, and hunger.

Hanni Rützler, nutritional scientist and researcher of food trends from Austria, views the project "Nemo's Garden" as a good start in this context. "There won't be just one technology dominating the earth over the coming decades. We need a wide range of options to feed the entire population. Under-water farming demonstrates the potential our earth has to offer."

Starting with basil

The project "Nemo's Garden" began in the summer of 2012. Sergio Gamberini installed the first biosphere anchored to the sea bed off the coast of Noli, a small Italian town. This was used to grow basil very successfully. He anchored two more biospheres, much larger in size, a year later. These biospheres are similar in concept to traditional greenhouses, but only have a volume of 800 litres. They are made up of a metal structure which is covered by a polymer film, like a balloon. "Biospheres are extremely resistant to sea water on the one hand, and on the other hand, they are very transparent so as to allow for incoming sunlight. Fruit and vegetables can thrive in them," says Sergio Gamberini.

The products grown in the biosphere do not require any pesticides due to their location deep in the sea. There are no pests there. Disruption of under-water ecosystems is thus avoided. Only a natural fertiliser is added to the plants. "However, we want to replace this with a product made out of algae in the future to create a completely sustainable life cycle in 'Nemo's Garden'," says Sergio Gamberini.

The biosphere generates the water required for plant growth on its own. Photos: Nemos Garden

Condensation ensures irrigation

The biosphere also generates the water required for plant growth on its own after a short time, since the air inside the balloon is warmer than the temperature of the sea water outside. The water evaporates and condenses on the inner walls of the balloon. This condensed water meets all the standards laid down for the irrigation of plants, and it would also have the potential to be used as drinking water. "Therefore, apart from the temperature of sea water, fruit and vegetables from our cultivation are not affected by the worldwide effects of climate change," says Sergio Gamberini, who sounds quite pleased about this.

The prerequisites for cultivation in the depths of the sea are: a biosphere that enables very high transmission of light, the different temperatures inside and outside the biosphere, and the resulting condensation of sea water. The key to a successful harvest and in turn the success of the project are "Agrinauts", a word created from "agriculture" and "astronaut" which describes the divers who regularly dive to individual biospheres to carry out maintenance, harvest vegetables and fruit or carry out scientific studies.

Growth begets attention

Research and development have paid off so far. The enthusiasm and the workload for "Nemo's Garden" showed an increase in 2014 and 2015. "We installed a biosphere with a volume of 2,000 litres in 2014. We were able to grow lettuce in it," Sergio Gamberini reminisces. The project gained considerably more media attention in 2015 and also attracted interested tourists who went diving. "We tried to grow different varieties of herbs, fruit, and vegetables in Nemo's Garden The conditions under water were not suitable to some, but a majority of them were grown successfully. "

"Nemo´s Garden" continued to grow steadily in 2016. Data collected over the entire growth cycle of the plant was evaluated, additional biospheres installed, and other types of fruit and vegetables were tested for cultivation. The quality and quantity of the plants reached its peak at this time.

Wide range of plants

An extensive range of products is being successfully grown in "Nemo's Garden". Herbs such as basil, thyme, oregano, and coriander can be found in the under-water farms along with lettuce, peas, courgette, tomatoes, and onions. Different varieties of flowers, aloe vera, stevia, honey melon sage, and other plants which can be used as natural remedies are also being grown.

However, harvesting these products is quite a complex undertaking for the team from "Nemo's Garden". "We are testing a system of farming here that has not been in existence until now. This presents new challenges, chief among them are the conditions at sea," says Sergio Gamberini. "Working under water requires a lot of physical energy, time, and technical resources. Added to this are environmental factors like changing tides, strong currents or waves."

Turning vision into science

Nevertheless, Sergio Gamberini and his team want to continue working meticulously in the future. They want to investigate to what extent the pressure generated under water has a positive effect on the growth of the plants. "However, the greatest challenge is to create an awareness for our cultivation methods as sustainable cultivation practice in the human consciousness. We want to explain and prove our observations in more detail with the help of different branches of science," says Sergio Gamberini. Should this come about, the vision of "Nemo's Garden" will have a better chance at being fulfilled in the future.

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