Researchers at NIOZ are testing Xiriton, a flexible, bio-based method for making temporary coastal building materials from local ingredients such as dried grass, volcanic pozzolan, crushed shells and seawater. In Yerseke trials, Xiriton blocks became about 70% covered by oysters, mussels and algae within a year, indicating strong potential as habitat-enhancing substrates. The material is presented as carbon-negative, uses non‑potable water, and can be tuned to break down naturally once ecosystems stabilize. Further testing, regulatory approval and scaling are needed before widespread adoption.
Xiriton: A Bio-Based, Temporary ‘Concrete’ That Helped Rebuild Coastal Life — 70% Coverage in One Year
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Researchers at the Royal Netherlands Institute for Sea Research (NIOZ) are piloting Xiriton, a bio-based method for producing temporary coastal building materials designed to strengthen shorelines while encouraging marine life to return.
What Is Xiriton?
Xiriton is not a single off-the-shelf product but a flexible production method that uses locally available ingredients to create nature-friendly construction blocks. Typical mixtures, according to NIOZ, include chopped dried grass, volcanic pozzolan, slaked lime, crushed shells, sand and seawater. Variants can be tailored to local resources and project goals.
Field Trials And Results
At NIOZ's Yerseke research site, researchers placed Xiriton blocks in an intertidal mudflat exposed to tides twice daily. The blocks were tested as realistic reef substrates to see whether they promote settlement by shellfish and algae.
"After a year, every block was around 70% covered with life such as oysters, mussels, and algae," said Ph.D. candidate and study co-author Victoria Mason, per NIOZ.
Environmental Advantages
The research team presents Xiriton as a carbon-negative, circular material that can be manufactured using non‑potable ditch or seawater (reducing demand for fresh water) and by incorporating recycled materials such as brick rubble or crushed seashells. Its binder reportedly strengthens with seawater and, importantly for ecological restoration, the material's lifetime can be tuned so blocks break down naturally into benign substances once a reef or marsh becomes self-sustaining rather than remaining permanently in the environment.
Context And Caveats
The need for nature-sensitive coastal solutions is growing: Cambridge University estimated about 2.15 billion people lived in coastal regions in 2023, and construction-related activity contributes a large share of global pollution — with cement production alone responsible for roughly 8% of global CO2 emissions. Xiriton could help reduce carbon and material footprints for coastal defenses, but it still requires regulatory approval, long-term ecological monitoring and industrial upscaling to verify durability, breakdown products, and broader environmental impacts.
Next Steps
The research team has already trialled Xiriton for shell banks and salt-marsh restoration and continues experiments to refine formulations, test longevity across environments, and explore pathways for permitting and commercial adoption. If regulators and industry adopt the method, Xiriton could become a scalable tool for ecologically sound coastal mitigation and habitat restoration.
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