The SEAREG project is developing a standard methodology to promote the growth of macroalgae in artificial substrates with algae of the genus Cystoseira, "seeding" them in structures that mimic natural reefs.
A crustacean in front of one of the reefs installed within the framework of the project. Image: Ocean Ecoestructures.
Researchers from the Centro de Estudios Avanzados de Blanes (CEAB) del CSIC are collaborating with the company Ocean Ecoestructures in the SEAREG project.
In this project, a nature-inspired solution is being developed to fight against the loss of biodiversity on the seabed through a system of artificial reefs that mimic natural ones. It is hoped that this pioneering technology "will make it possible to use marine infrastructures and turn them into vectors of renaturalisation", says Anna Lloveras, CSO of Ocean Ecoestructures.
Recovering marine forests
Cystoseira are a family of macroalgae from temperate regions such as the Mediterranean. They are structural algae, that is, they offer shelter and habitat to many invertebrate organisms, fish and other smaller algae or marine lichens, which grow on them. They form forests from the surface to a depth of 60 meters and are indicators of good water quality.
Unfortunately, they are very sensitive species, and currently are strongly threatened and in decline. Some sources indicate that 80% of Cystoseira's forests have been lost or are at a critical point, so scientists have been studying conservation and restoration strategies.
Replanted cystoseira recruits. Image: Ocean Ecoestructures.
Emma Cebrián, a researcher at the CEAB-CSIC, explains that "some time ago we managed to describe a non-destructive restoration method, which allow us to take fragments of the algae at the time when are fertile enough, to 'seed' them in the laboratory and transplant them into their natural ecosystem". Now, this technique is being implemented through a public-private collaboration agreement with Ocean Ecoestructures.
SEAREG project addresses all stages of the replanting process, including the collection of fertile fragments in natural environments, from which new algae can reproduce. The propagules are grown under controlled laboratory conditions, to optimize the factors that favour their development.
A fundamental step is the design and adaptation of the pre-seeding system, developed by Ocean Ecoestructures, to facilitate the settlement of recruits. The system has been adjusted to be compatible with different species and phases of the life cycle of Cystoseira algae, in collaboration with the CEAB-CSIC team.
However, work is also being done to adjust it to Posidonia oceanica and gorgonians, which have a slower growth. For these, researchers from the del Instituto de Ciencias del Mar (ICM-CSIC and from the Instituto Mediterráneo de Estudios Avanzados (IMEDEA), -a joint centre of the CSIC and the University of the Balearic Islands (UIB)- are collaborating.
The system has been adjusted to be compatible with different species and phases of the life cycle of Cystoseira algae. However, scientists are working also to adjust it to Posidonia oceanica and gorgonians, which have a slower growth
One of the nature-mimicking reefs installed in the project, covered by different algae such as Dcityota. In the background you can see one of the structures, still in the process of being covered by algae. Image: Ocean Ecoestructures.
Mimicking natural reefs
After pre-seeding, the units are transferred to marine renaturalization structures or LBUs (acronym for Life Boosting Units), biomimetic reefs developed by Ocean Ecoestructures.
Both the pre-sowing units and the LBU units are based on a natural substrate such as calcium carbonate – the same material as coral – with the aim of mimicking nature and recovering marine fauna and flora. As the company explains, they have a multi-layer design to generate a "nursery effect" that facilitates the growth of fish and crustaceans, as well as a specific fixing system that allows them to be placed on any surface without interfering with port operations or offshore platforms.
LBUs are already marketed, as other products of the company, such as Seabed Units. The development of the SEAREG methodology is in the phase of validation and optimization.
"We already have more than 300 LBU installed in commercial marine ports and offshore platforms," explains Anna Lloveras. "Additionally, we have designed a system that is easy and quick to install. The biggest challenge today is the production time, since we use an electrolytic system that covers the mineral structures, basically calcium carbonate, and it is a slow process, which lasts from 4 to 6 months".
Installation of the structures
Anna Lloveras explains that "the solutions that are being developed must be a tool for replanting to be scalable, so the cost and efficiency variables are important".
For this reason, the system is being designed to be able to install the preseeding units using remotely operated vehicles or ROVs (Remoted Operated Vehicle), without the need for divers.
In this sense, different partners collaborate in all phases of the project. CSIC researchers are the ones who have the knowledge of ecology and also the experience of reforestation, so "we work with them to adapt the technique, so that it is scalable and adapts to our system," says Lloveras. Other partners, such as Eurecat and BCN3Ceramics, help in the development of materials and in the design of the "most efficient and sustainable tools”.
Harbours such as the ones of Barcelona, Bilbao and Algeciras are also partners, where the structures are installed and repopulation tasks are carried out. Experiments are currently being carried out in real conditions in Marina Palamós, Club Nàutic Vilanova and Club Nàutic Estartit to evaluate the effectiveness of the methodology. "Before carrying out any replanting, we consult the expert committee to define the objective of each project and validate its feasibility".
Surveillance by ROV robots
UOnce the LBUs have been installed, the process of the reforestation is monitored. The system is designed so that ROVs can obtain all the necessary information through video images, photos, a multi-parameter probe and a built-in niskin bottle.
The videos are analysed using AI systems, which identify more than 80 species (benthic and mobile) and, among other things, can calculate the surface area they cover, the biomass and the fixed CO2, as well as the parameters of water quality.
One of the artificial substrate systems. Image: Ocean Ecoestructures.
The system also allows for the surveillance of invasive species, although for now, it only detects those that can be visually identified in the images captured by the ROV. If another method is needed to detect invasive species, samples are collected and the results are confirmed by the group led by Xavier Turón from the CEAB, experts in monitoring marine biodiversity using DNA. "We are currently working to incorporate DNA analysis into our protocol to improve the detection of these species," adds Lloveras.
SEAREG is a first step to "promote the growth of plant species in artificial substrates. In the case of ports, with a high human impact, it has benefits such as increased biodiversity. The ideal future of marine restoration, says Emma Cebrián, will also be to be able to recover other points of the coast, which recover the functioning of the ecosystem, the balance in biodiversity, the normal flows of carbon and oxygen, restoring ecosystems that are self-sustaining, in short.
This work is part of European and national funding projects, such as EFFECTIVE and ECOFOSS, which support applied research in the recovery of marine ecosystems through innovative techniques for restocking ecologically important macroalgae. A public-private collaboration contract has also been signed in which the CSIC's Vice-Presidency for Innovation and Transfer is supporting the results of projects like these with a great environmental impact to be valued," says Isabel Gavilanes, knowledge transfer officer at the CSIC Delegation in Catalonia.