ReefSystems – Underwater nature enhancing solutions

The western harbor area of Amsterdam is home to Prodock, an “incubator” for innovative startups with one shared goal: contributing to sustainability. ReefSystems is one of them. This Dutch startup was one of the nominees for the Offshore Wind Innovation Challenge 2020 award.

Jesse de Bont and Max Dijkstra give a tour of the warehouse where the two partners in ReefSystems are working hard on three different innovations that are all aimed at stimulating biodiversity, in this case underwater.

It all started with MOSES (Modular Sealife System), a multifunctional, easy to install, modular artificial reef system. The idea came from Dijkstra: “I wanted to create objects that are nature enhancing and would still be there after I was gone.” He approached the University of Wageningen and worked with a professor who specialized in marine ecology on his final project. This he completed in 2018. After a few years of working alone, he got into a conversation with childhood friend De Bont and they decided to work together.

At that time, the MOSES system was already being tested for the first time on the outside of the Brouwers Dam, where the introduction of the Haringvliet locks had reduced biodiversity. With De Bont’s business acumen, two funds were soon brought in. From that moment on things went fast.

Text continues below the image

MOSES-system at Brouwersdam

Offshore Wind Innovation Challenge

The MOSES system also prompted Offshore Wind Innovators to contact the men and interest them in participating in the annual Offshore Wind Innovation Challenge. Could ReefSystems perhaps also come up with a biodegradable version, one that would last for 25 years, was the question. “We immediately started brainstorming and submitted the application,” says Dijkstra. In doing so, with each step further, they eventually ended up in the finals.

The final design is a biodegradable block that can be placed on the seabed in offshore wind farms, creating a shellfish reef where fish and reefs can grow and multiply safely. To do this, they experimented with different types of materials to make the blocks biodegradable, such as calcium-containing tabby concrete, solanyl: a biodegradable plastic made from starch from potato peels, flax fibers, manila rope and artificial scouring protection from seaweed. As the shell reef grows, the object slowly disappears. When the reef is complete, the man-made object is completely gone.

“The whole development was fun and educational, we did an awful lot of figuring out how to make this system economically feasible and in doing so, what obstacles were to overcome in terms of installation, efficiency, affordability and building locally,” De Bont tells.

At the moment the project is on hold for a while. That is unfortunate for both men, but they are ready if there is need or if an opportunity rises where they can do a pilot with De Rijke Noordzee. All they need is a budget, they can do the entire production in-house. “It’s a long and difficult process,” says De Bont. “There are a lot of requirements. End users have to be convinced of the innovation and that it constitutes a safe and biological solution for the stimulation of biodiversity. As a startup, of course, you want everything to go a little faster.”

Text continues below the image



While the biodegradable reef is still waiting, Dijkstra and De Bont are busy with their other innovations. They have designed SPECTER, a multi-layered hanging case that can be attached to dam walls below the waterline. In it, native aquatic plants are placed in burlap sacks. After a season, the roots of the plants grow through the sacks and attach themselves to the case. The hanging cases serve as hiding places for fish, which in turn is good for fish migration. The innovation is in line with the EU Water Framework Directive in terms of water quality and biodiversity. The innovation is being tested at five sites and, if proven successful, is an ideal product for water authorities.

First large-scale commercial project with MOSES

MOSES system – applied in Kenia

With the MOSES system, ReefSystems is already well on the way. The first system installed in Zeeland proved to be a success. Within a year it was already completely covered with aquatic vegetation and attracting underwater species. When the men moved into Prodock they were asked by the Port of Amsterdam if they could also install it in the Noordzeekanaal. They selected three locations. Meanwhile the reef blocks are also being applied in Panama (in partnership with Boskalis and other parties) and Kenya, as substrate for new reef in places where the old reef has been destroyed or damaged.

This summer they also won their first commercial contract for the MOSES system. For a combination project of dike reinforcement and biodiversity stimulation near Lauwersoog on the Wadden Sea, ReefSystems will install thirteen structures that function as artificial reefs. They were awarded the contract by contractor Heijmans and engineering firm Arcadis. The installation will take place in the first week of November. The structures will be spread over a number of kilometers and monitored for two years by researchers from two universities. The monitoring should show what works best and is cost-effective, after which a decision will be made whether to extend the project along nine kilometers of dike. Production is already in full swing.

Large-scale production and testing at Deltares

Testing at Deltares

In August, a new machine was put into operation. A mechanical engineer designed a semi-automatic mould. With the new acquisition, large-scale production is now possible. Previously this was limited to five structures per day. The new machine, and related increased production capacity, allows ReefSystems to offer the product more cheaply.

In the meantime, the company is also developing a new connecting system. De Bont: “Up to now we glue the constructions together with marine epoxy. With the new moulds we are also introducing a new connecting system. By using a bolt-nut system we can guarantee that the connections will be able to withstand storms. We will test the stability and strength of our structures in cooperation with TU Delft at Deltares’ wave test facilities.”

Win-win situation

Actually, the more permanent MOSES system could just as well be used for wind farms, both agree. At least, if regulations no longer dictate that the structure must be removed along with the wind turbine after x-number of years. “If the artificial reef supports nature development in wind farms, then leave it in place. If you remove the reef you will destroy everything,” says Dijkstra. “Encourage wind farms to become multifunctional aquaculture, where seaweed, oysters and mussels can be grown and fish attracted. This will create a spill-over effect of kilometers around the wind farm. The fishing industry then benefits from that as well.”

Moreover, by linking the system to another function such as protection against erosion at the base of a wind turbine or on a submarine cable or as an ecological add-on for anchoring systems in, for example, seaweed production or floating solar parks within wind farms, a win-win situation is created for everyone.


Although the innovations of Dijkstra en De Bont contribute to the absorption of CO2, it is also important for the men to make the production process as CO2-neutral as possible. They have been working with as many recycled materials as possible from the start. They are also working with concrete experts to increase CO2 neutrality by working with bio-cement. Dijkstra: “R&D is important to us, by continuing to innovate we can keep sustainability high.”

The men realize that with their mission to create products that enhance biodiversity they have not chosen the easiest path, because nature itself obviously does not pay. Fortunately they can tell that there is growing consciousness that people also benefit from more biodiversity and that there is now a need for this. In combination with another function such as dyke reinforcement, breakwater, anchoring, erosion protection and so on, there is, as mentioned earlier with wind farms, ultimately a win-win situation for everyone.

Text: Sabine Lankhorst

This article appeared in the September edition of Windpowernl. All images: copyright ReefSystems

Input your search keywords and press Enter.