During the week of the 20th of June, researchers from MARE-IPL and CIIMAR were in Peniche to deploy the first batch of green gravel under the BlueForests project. The aim is to test and optimise the technique for the purpose of restoring Laminaria ochroleuca kelp forests across the Portuguese coastline.

Despite their importance, kelp forests have experienced severe global declines over the past decades with a consequent loss of the habitat’s associated biodiversity and ecosystem services. Portugal is no exception and has lost much of its historic abundance of these productive ecosystems. The BlueForests project aims to test and optimise several seaforestation methods to recover kelp forest habitats, focussing on the golden kelp, Laminaria ochroleuca. Green gravel was chosen as one of the techniques as it can provide a low-cost and scalable solution to restore kelp ecosystems at a scale that matches past damage and current trends of decline.

The technique is based on existing seaweed cultivation methods, recently adapted to restoration, where substrates, in this case small stones, are seeded with kelp spores in land-based nurseries, cultivated for a period of time, and then out-planted on damaged reefs, where they can establish full canopies and eventually reseed adjacent areas of seafloor.

Reproductive tissue, also called sorus, was collected from local kelp populations in Viana do Castelo to produce stock cultures that were seeded onto granite stones in the nursery facilities of MARE-IPL and CIIMAR in March this year. After around 3 months of cultivation, the gravel was ready to be deployed at sea.

The deployment was done in front of São Bernardino, south of the Peniche peninsula, at a depth of 16 m, covering an area of approximately 30 m2. The size of the restoration area will steadily be increased through additional deployments and its development assessed though frequent monitoring campaigns.