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Bioinspired controlled crystallisation: Towards sustainable artificial coral reefs

2025/04/242025/04/28

Inspired by nature, scientists have replicated some aspects of the biomineralisation process used by marine organisms like corals, enabling them to control crystal phases in materials. This advancement could lead, among others, to artificial coral reefs that seamlessly integrate into marine environments without disrupting the ecosystem. Their results are out in Advanced Functional Materials.

Artificial coral reefs are often made of concrete or steel to provide stable structures for a marine habitat. However, they can also foster biofilm formation, promoting bacterial growth that may influence water chemistry.

Now a team led by Boaz Pokroy at Technion Israel Institute of Technology is working on artificial coral reefs that are as close to their natural counterparts as possible by reproducing the biomineralisation process typical of coral reefs and other marine organisms.

“For many years, we’ve extensively studied many marine organisms, such as the coralline alga Jania sp., sea urchins, starfish or brittle stars, and have unveiled the steps these organisms take to create a super hard skeleton through the process of biomineralisation”, explains Pokroy.

The natural process of biomineralisation starts as an amorphous phase before transforming into crystalline stable structures.

A key player in in this process is amorphous calcium carbonate (ACC), a precursor that can crystallise into different forms of calcium carbonate, including calcite, aragonite, and vaterite. The stability of ACC is influenced, among other factors, by impurities like magnesium, which affects the final crystal structure and properties. Traditionally, controlling this transformation required chemical additives and environmental adjustments.

Pokroy and his team used lasers to selectively transform ACC into different mineral phases. Laser power, scanning speed and the composition of the substrate are factors that affect the process of formation of distinct crystalline phases.

As the next step, the powders were analysed using synchrotron high-resolution powder X-ray diffraction (HR-PXRD) to identify the phases formed. “The experiments on beamline ID22 at the ESRF were crucial to characterise the different phases and track the impurities in the sample”, explains Hadar Shaked, scientist at Technion and first author of the publication. “With EBS providing higher flux, we were able to scan hundreds of samples in a very short time”, adds Pokroy.

Engineering bio-inspired materials

This method represents a significant advancement in bio-inspired material science, offering a way to engineer complex mineral structures with the same spatial accuracy seen in biological systems. “Whilst crystallisation from an amorphous phase was already possible through heating, it is the first time that we have full control of the process, which is key in engineering new structures as we wish”, says Shaked.

Dubbed ‘writing crystallography’, this approach opens exciting possibilities not only for artificial coral reefs but also for advanced additive manufacturing, semiconductors or single-layer patterning, where precise phase control is essential.

Research on sand near Hiroshima shows fallout debris from A-Bomb blast

2019/05/132019/05/14

X-ray studies at Berkeley Lab provide evidence for source of exotic assortment of melt debris

Mario Wannier, a career geologist with expertise in studying tiny marine life, was methodically sorting through particles in samples of beach sand from Japan’s Motoujina Peninsula when he spotted something unexpected: a number of tiny, glassy spheres and other unusual objects.
Wannier, who is now retired, had been comparing biological debris in beach sands from different areas in an effort to gauge the health of local and regional marine ecosystems. The work involved examining each sand particle in a sample under a microscope, and with a fine brush, separating particles of interest from grains of sediment into a tray for further study.

Image: Researchers collected and studied beach sands from locations near Hiroshima including Japan’s Miyajima Island, home to this torii gate, which at high tide is surrounded by water. The torii and associated Itsukushima Shinto Shrine, near the city of Hiroshima, are popular tourist attractions. The sand samples contained a unique collection of particles, including several that were studied at Berkeley Lab and UC Berkeley.
Credit: Ajay Suresh/Wikimedia Commons

Direct and Efficient Utilization of Solid-phase Iron by Diatoms

2017/07/312018/01/18

A research team indicates that diatoms, can directly uptake iron from insoluble iron sediments, and thereby potentially affect atmospheric carbon dioxide level.

A research team from Columbia University indicates that diatoms, photosynthetic marine organisms responsible for as much as 20% of photosynthesis in the world’s oceans, can directly uptake iron from insoluble iron sediments, and thereby potentially affect atmospheric carbon dioxide level. Although iron is often present in the ocean, usually there is insufficient iron for diatoms and other organisms to grow quickly unless this iron is dissolved and in a form that can be used readily. This research establishes that iron from mineral phases can be quite bioavailable, and that the diatoms can use most forms of iron, but appear to have a preference for a specific form of iron, ferrous iron, in the mineral phases. This research is applicable to a wide variety of questions in earth and ocean sciences, including basic biology of nutrient acquisition, the coupling of physical and geological processes such as glaciers to climate and geoengineering.

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Picture: Glacial striations seen near Upsala Glacier, Argentina, where scientists collected glacial samples. This physical scraping produces sediments and dust that can fertilize plankton when it is delivered to the ocean.
Photo by Michael Kaplan/Lamont-Doherty Earth Observatory