Dutch start-up Reefy saves coral reefs and protects the coast By: André Oerlemans Restoring dying coral while protecting coasts and beaches from rising sea levels and increasing storms and hurricanes. The Dutch start-up Reefy has developed a solution for this with artificially constructed coral reefs on sustainable concrete blocks. Thanks to a subsidy from InnovationQuarter, the regional development company for South Holland, and three other investors, Reefy can start two pilots in the Netherlands and Mexico to prove that the technology works. “We will start the first pilot in Rotterdam in January and in Mexico in the course of next year,” says Reefy co-founder Leon Haines. Coral reef dies en masse Although they only cover 0.01 percent of the ocean's surface, coral reefs are home to 25 percent of all marine life. They are a source of food and income for billions of people. They also protect more than 200 million people on earth against flooding and erosion of beaches and coasts. A healthy coral reef absorbs 97 percent of the wave energy before it reaches the coast. Coral is very fragile and very sensitive to pollution and temperature rise. In the past thirty years, half of the world's coral reef has died and disappeared. It is expected that by the end of this century 90 percent will not have survived climate change. The Great Barrier Reef in Australia, the largest coral reef in the world at 2,300 kilometers in length and the only cluster of living organisms on Earth visible from space, has already lost half of its coral. A third died of bleaching in the past two years as water temperatures rose. Disaster for man and nature Dead coral reefs are not only a disaster for nature and the people who depend on them, it also no longer protects the coast. The seabed becomes flat and no longer absorbs wave energy. Therefore, there is a great need for artificial coral reefs, but most solutions pollute the marine environment or have a negative effect on marine life. 3D-printed coral reefs have also been deployed, but they do not have a breakwater function and do not protect the coast. Coastal protection Reefy has developed a kind of low-cement, concrete Lego blocks with holes on which coral can grow, which also act as breakwaters. Fish, lobsters and other sea creatures can hide in the cavities or spaces under the blocks. These blocks can be placed on and against each other in all sorts of ways on the seabed, usually about a hundred meters from the coast. This creates a relief landscape that is comparable to natural coral reefs and in the same way protects the coast against waves and storms. The first blocks have been tested against hurricane force at Deltares in Delft. Grow faster By giving pieces of coral broken off by storms or anchors a second chance and sticking them on the blocks, the artificial reef grows faster than normal and results are visible after just a few years. This has been tested in the tropical aquariums of the Oceanium of Blijdorp zoo in Rotterdam. “We have also already tested cement-free concrete blocks that are CO2 negative in order to build the artificial reefs sustainably. We also constantly adjust the substrate so that the coral can grow extra well on it," says Haines. "Our reefs form natural breakwaters that can grow with sea level rise and repair themselves after a storm." Contact via Instagram Founders Jaime Ascencio and Leon Haines got in touch via Instagram. Ascencio is from Mexico, where he worked as a coastal defense engineer, selling concrete structures that could protect resort beaches from storms and sea level rise. He moved to the Netherlands to study hydraulic engineering at TU Delft and to look for a sustainable solution. He then spent a year researching natural ecosystems that protect coasts at Deltares. That's where the idea for Reefy was born. Haines studied marine biology in Leeuwarden and after his studies started working for coral reef restoration projects in Thailand, the Maldives and Indonesia. In the latter country, he started Conservation Diver on a small island group near Lombok, which provides courses for divers to conserve, restore and protect the coral reef. “That project has been able to restore very nice pieces of coral, but it is a drop in the ocean,” says Haines. “We want to make an impact on a larger scale by combining coral reefs with coastal defense.” The project did bring the two together, because Ascencio saw it on Instagram and got in touch. Haines came to the Netherlands from tropical places again and in 2020 they founded Reefy together. saving tourism in Mexico With the new investment money, Reefy can expand the team and start the first pilots. In Mexico, the start-up will place its artificial reefs at a beach resort on the tourist coast of the Yucatán Peninsula. The endangered coral reef there is part of the Mesoamerican Coral Reef, the second longest coral reef in the world after Australia's Great Barrier Reef. The reef is also important to the many resorts that are in danger of losing not only their diving and snorkeling sites, but also their beaches. Haines: “In Mexico they don't have a Rijkswaterstaat like here and the resorts have to construct their breakwaters themselves. They are now looking for sustainable solutions like ours to strengthen their coast.” The Rotterdam Reef In the Netherlands, the sustainable Lego blocks will be placed in the Groene Poort project near Rozenburg, which aims to construct sustainable banks in the Nieuwe Waterweg. Reefy's project is called The Rotterdam Reef and is a collaboration with the municipality of Rotterdam, Rijkswaterstaat and Boskalis. The spit of land in the Nieuwe Waterweg is being reinforced with an artificial reef, a kind of ecological breakwater of four kilometers in length. “It protects the banks and forms a natural habitat for oysters and bladder wracks,” Haines explains.