Seabed crops make a ripple
IN the homeland of pesto, a group of diving enthusiasts has come up with a way of growing basil beneath the sea that could revolutionise crop production in arid coastal areas around the world.
The pungent green herb has long been synonymous with the steep, terraced cliffsides of Liguria, the northern Italian region known for its spectacular coastline and for producing one of the world’s best- loved pasta sauces.
Those two standout features of the region could now become even more intimately associated, thanks to the efforts of Sergio Gamberini.
A diving nut and specialist in underwater communications, Gamberini has begun growing basil in large plastic spheres anchored to the sea bed 100 metres offshore and eight metres below the surface in an experiment he has dubbed “Nemo’s garden”.
“The idea came to me because I wanted to create more interaction between the surface and the diving activity,” Gamberini said.
Having started with a simple plastic ball into which he placed a tub with herb seeds planted in compost, he is now in his fourth season of production from an underwater garden comprised of three “biospheres” which he is allowed to keep in the water for three months a year.
“I chose a typical activity of farmers, and I said ‘ why not bring it under water?’” he said.
“I realised that there was an opportunity to create a new site to grow vegetables.”
Evaporation ensures humidity between 80 and 90 per cent inside the spheres, the condensation provides the necessary moisture and, even well below the waves, there is enough light to ensure the plants regenerate their oxygen supply via photosynthesis.
Having proved the system works, Gamberini’s challenge now is cost- efficiency.
“I don’t know if it will be the future because we have to prove that it can be selfsupportable,” he said. “If a pound of lettuce ( grown underwater) costs too much, it won’t have a future.”
The primary advantage of underwater growing is the stability of thermal conditions.
“The sea maintains the temperature without a great difference between day and night,” said Gianni Fontanesi, who runs the project.
In late June, the water on the coastal shelf of the northern Mediterranean is 25 degrees, while inside the spheres the temperature reaches 29 degrees. The plants are thriving in an environment where they are protected from insects and parasites.
The results have been encouraging, with the spheres producing more densely leafed plants than is usual.
“In the longer term, this could be a solution for arid regions next to the sea,” said Gamberini, who admits there is still much work to be done to do it on a larger scale.
CONTROLLED ENVIRONMENT: Project co- ordinator of Nemo's Garden, Gianni Fontanesi, checks his underwater crop in immersed biospheres off the coast of Italy.