In Calvi Bay in Corsica, the planting season runs from June to early August, and the STARESO team called the 2026-one a really good season.

STARESO plants the Posidonia oceanica seagrass in a smart way. Divers transplant seagrass plots in a checkerboard pattern. Over time, the seagrass spreads into the sandy gaps between the plots. This season, the team transplanted 130 m² of seagrass, spread over 1,000 to 1,500 m² of seabed. That whole area can gradually turn back into meadow. The ambition goes much further. Over the next 5 to 10 years, we aim to restore 10,000 m². At that scale, the restored meadow would reconnect with the natural Posidonia meadow that still grows in the eastern part of the bay.

Posidonia meadows store carbon in their "matte", the thick layer of roots and sediment they build up over centuries. In Calvi Bay, a healthy meadow stores about 169 g of CO₂ per square metre each year over the long term. Each square metre planted can grow into around ten square metres of meadow. That gives a long-term potential of about 1.7 kg of CO₂ per year for every square metre patch planted. This is a potential, not a claim. It only applies once the full area has grown into an established meadow, and it does not apply in the year of planting. To measure the real effect, we will start monitoring next year, together with the University of Liège. The monitoring will also compare the meadow with what the bare seabed would have stored without restoration.

The first Go Ocean seagrass in Calvi Bay will be transplanted during the 2027 planting season. Stay tuned!