After months of loving care, the young Cystoseira seedlings are ready to be taken to their future home, along the coast south of Agropoli, in south Italy. Having grown vigorously on hundreds of clay discs, their journey to join the other plots already established in previous years will be completed in the coming days.
The process that has enabled all these algae to reach the transplant stage is the one that has now been tried and tested abundantly in REEForest: starting with the meticulous collection of fertile tips and cultivation in a controlled environment, until the “refuge size” of the plants is reached. That is the size threshold beyond which the seedlings have a realistic chance of survival once returned to their natural environment.
More than 600 discs have thus left the laboratories in Trieste to reach the Cilento coast, transported in specialised tanks prepared by researchers from the University of Trieste. It is these researchers who are overseeing this delicate phase. The aim is to ensure that the young Cystoseira arrives at its destination in the best possible condition. For this transplant site, Parthenope University of Naples is the lead partner within the Santa Maria di Castellabate Marine Protected Area.
Upon arrival at the restoration sites, the team – comprising divers from Parthenope University and researchers from Shoreline – set to work immediately, making the most of the only window of opportunity available before weather conditions deteriorated too much, which risked preventing the outplanting operations.
The divers first lowered the transplant units onto the seabed. These are pre-fabricated metal structures designed to provide structural support for the discs and to avoid offering too much resistance to wave motion, which could destroy the installation. Once in position, the grids filled with Cystoseira were securely fixed to the rock at the correct depth in the areas where the absence of brown algae is most evident.
This mission is not just about the new arrivals: many of the “veteran” discs – those from the very first installation in 2023 – have also emerged from the seabed.
Over the last three years, these thalli have thrived on top of the previous supports and have grown considerably, but other invasive marine organisms have also developed alongside them. Smaller species of algae and all manner of micro-invertebrates have utilised the spatial complexity of the Cystoseira to settle on top of the discs and amongst the branches of the brown algae itself.
Before being placed in position, these discs were carefully cleaned – either by spraying them with water or gently scrubbing them with a small brush – to remove encrustations, epiphytes and sediment that might have hindered their further development. Consequently, the researchers had to carry out maintenance work on these structures to remove all these epiphytes too.
Excessive proliferation of these epiphytes can hinder the development of Cystoseira by smothering it before it can reach a considerable size.
Finally, relocating them directly onto the rocks increases the chances of those thalli reaching maturity in the very same stretch of sea where they have already proven capable of surviving.
The result of this campaign is therefore a mosaic of algae of varying ages and experiences. The new arrivals and the survivors will now have to endure three more seasons before further reinforcements arrive next spring.
The next step is, as always, monitoring: only in the coming months will we discover how many of these algae, both old and new, will manage to thrive right there, in the very places where the marine forest had disappeared
