When Jules Verne created Captain Nemo, he could not imagine that his fantasy would one day become reality: an underwater greenhouse built in Noli, on the western Ligurian coast. L'Orto di Nemo is the first underwater hydroponic cultivation project, an idea born from the Genoese engineer Sergio Gamberini, when about 8 years ago he anchored a transparent pocket of air to the bottom of the sea. The results were extraordinary, so much so that research was pushed in this direction especially thanks to the 2015 Expo. The project, however, is still in the testing phase, to better study the dynamics that are triggered within these biospheres. So far, the best results have been obtained with basil and other aromatic herbs, such as stevia, salads, goji berries and aloe.
However, figuring out which plants are suitable for this type of experimentation is not easy. To help a team of agronomists from the University of Pisa, who are carrying out various research to select which types to carry out the tests on. The university is one of the scientific partners of the Orto di Nemo, a project started 8 years ago and promoted by Mestel Safety of the Ocean Reef group, a company that deals with underwater instruments, with the aim of creating an alternative system of agriculture for areas where climatic or economic conditions make it more difficult for vegetables to grow on land.
The most suitable is basil (the hydroponic plant that can grow even without soil), which is grown in methacrylate biospheres of 2 meters in diameter, sort of transparent air-filled balloons (about 2 liters in volume), immersed in the sea between 6 and 10 meters deep. Once anchored with chains on the seabed, the air is blown inside which, being lighter, is positioned in the upper part.
Such underwater greenhouses can contain from 65 to 95 seedlings. These are ecological and self-sustainable structures that do not pollute our sea: the sunlight penetrates the surface and warms the air, until it reaches the plant inside the biosphere and, at the same time, the water contained inside inside it evaporates without salts, becoming sweet. In this way water is automatically supplied to the plant, without the need for additional energy, collected through capacitors to feed the plants. Fertilizer brought from the surface is then added to the demyralised water.
In order not to waste the water during the day, it is made to slide thanks to a system of pipes into the support of the plants, in a continuous cycle. The system is regulated from the shore through a control unit powered by solar energy and at night, however, it is provided with lights positioned inside each dome.
According to the results, basil grown in underwater biospheres is greener, aromatic and rich in antioxidant substances (polyphenols). Furthermore, the high presence of methyl eugenol makes it even more fragrant than the classic Genoese basil. Also production is much faster compared to traditional methods: in less than 2 days the seed is transformed into a young plant, against 5/7 days on dry land. Sometimes, there is a difference in the size of the leaves (the carotenoids increase), but as far as the taste is concerned, there are no big differences.
All characteristics that differentiate it from the one grown on balconies, thanks to the constant temperature (around 26°C), rather high humidity (which can even reach 90%), but above all the absence of insects and parasites so as to avoid the use of pesticides.
It seems simple, but in reality there are many difficulties that researchers have encountered in this adventure. For example, you need astate authorization to mount and fix the biospheres. At the beginning there were time limits, currently the permit has been granted all year round, so as to push the research of this new cultivation technique. In addition, plants suffer from salt water and direct sun exposure, so you need to pay close attention when you touch them or bring them to the surface, but above all you need to keep the biosphere clean so that it is not covered by marine life, blocking the light to filter. In fact, the garden is monitored 24 hours a day.
A real revolution in agriculture as we know it. This system solves quite a few problems in those areas which, due to lack of land or fresh water or even parasites or excessive temperature variations, make it impossible to grow certain products. For the future? One thinks of automation and water and energy independence.
