A diver collects Cystoseira cuttings from the seabed off the Greek island of Gyaros in the Saronic Gulf. Cystoseira is a genus ofalgae brown, very sensitive to water pollution and often used as a biological indicator of the state of the sea.
Replanting underwater forests to restore the Greek islands
Divers from the Hellenic Marine Research Centre transplant cuttings of Cystoseira, an algae vital to the survival of the Mediterranean.
BarcelonaRising temperatures, human pressure, overfishing and pollution are leading to Mother Nostrum at a point of no return. There are many scientific voices warning.
At a an initiative similar to those that exist in Catalan and Balearic waters, On the Greek island of Gyaros in the Saronic Gulf, a group of scientists from the Hellenic Centre for Marine Research are working on a project of extreme difficulty and no small importance: repopulating the rocks of the coastal seabed with cuttings of Cystoseira, a rapidly disappearing species of brown algae that sustains biodiversity. Reuters photographer Stelios Misinas dived with them to show us, in detail, the laborious process they use to collect, cultivate, and finally replant the algae.
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A temperate climate algae
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The harvest
Maria Salomidi, a marine ecologist at the Hellenic Centre for Marine Research, collecting Cystoseira to grow cuttings in the lab.
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Cultivation in the laboratory
Oceanographer Andrea Ramirez prepares nutrient solutions for Cystoseira cultivation at the Hellenic Centre for Marine Research (HCMR) laboratory in Anavyssos, near Athens, Greece.
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In the laboratory
The cuttings of Cystoseira They are manipulated in the laboratory. The algae species is rapidly disappearing, and reversing this situation is vitally important because it is key to maintaining coastal biodiversity in the Mediterranean.
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The cuttings
Cystoseira cuttings are placed on clay tiles for laboratory cultivation at the Hellenic Centre for Marine Research (HCMR). Cystoseira is one of the most widely distributed algal genera in temperate regions of the Northern Hemisphere, such as the Mediterranean, and provides essential habitat for many invertebrate and fish species.
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A successful project
Once the plants are prepared, the divers transport the Cystoseira cuttings back to the sea, so they can be replanted. It is a complicated and extremely difficult to be successful oneforests are lost time and time again.
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Prepare the ground
Researchers from the Hellenic Center for Marine Research (HCMR) drill into coastal rock to prepare it for transplantation at Cystoseira, Greece, June 3, 2025.
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The transplant
A diver screws a clay tile used for growing Cystoseira onto an underwater rock surface during a transplant operation.
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An underwater forest
A replanted underwater forest of Cystoseira on the Greek island of Gyaros in the Saronic Gulf, May 21, 2025.