3D-printed corals, carbon dioxide sequestered in the sea, plastic stopped in rivers: three startups working for the future of the oceans.
They cover more than 70 per cent of the planet, produce at least half of the oxygen we breathe, absorb around a quarter of the carbon dioxide emissions generated by human activities, and are home to the majority of global biodiversity. Yet the oceans are among the most pressured natural systems on Earth: warming, acidification, overfishing, coral bleaching and plastic pollution all threaten their health. In 2023, the average global sea surface temperature reached record levels, and between 2023 and 2024 exceptionally intense and prolonged marine heat waves struck the Atlantic, Pacific, Caribbean and Mediterranean.
According to the National Oceanic and Atmospheric Administration (Noaa) and the International Coral Reef Initiative, between 2023 and 2025 the fourth global coral bleaching event ever documented took place: bleaching-level heat affected more than 80 per cent of the planet's coral reefs, threatening the survival of corals and, with them, entire marine ecosystems that depend on them. On top of this, more than 11 million tonnes of plastic end up in the oceans every year, according to United Nations estimates.
World Oceans Day, established by the UN in 2008 and celebrated every year on 8 June, is the moment when governments, the scientific community and citizens come together to discuss how to protect these ecosystems. For 2026, the United Nations has chosen the theme Reimagine: an invitation to rethink our relationship with the sea, no longer seen as an inexhaustible resource, but as a living system to be protected, regenerated and governed with greater responsibility. A direction that also runs through new, innovative solutions capable of addressing different fronts: habitat regeneration, carbon dioxide removal, and pollution prevention before it reaches the sea. We have chosen three, each carried forward by a startup that, from very different angles, is working to safeguard the future of the oceans.
Founded in Switzerland by four women with backgrounds in marine biology, architecture and design, Rrreefs works on the regeneration of coral reefs starting from a simple insight: recreating the complex structures that corals build in nature, to offer a base on which they can reattach and grow.
The solution is a modular system of 3D-printed clay elements — a ceramic material compatible with the marine environment — designed to mimic the geometries of natural reefs. The modules are placed on the seabed and quickly become habitat for fish, invertebrates and new coral colonies.
Today Rrreefs' projects are active in Ecuador, Colombia, the British Virgin Islands, the Philippines and the Maldives, always through partnerships with local communities, which are involved in the maintenance and monitoring of the reefs. Since 2023, the startup has transformed its model from a non-profit association to an impact enterprise: individuals and companies can become co-owners or partners of the reefs, integrating coral regeneration into their own sustainability strategies.
Where Rrreefs works on ecosystems, the Italian deep-tech company Limenet tackles the problem at its source: atmospheric carbon dioxide, the main driver of global warming and ocean acidification. Its patented technology exploits a chemical process that transforms carbon dioxide into stable bicarbonates dissolved in seawater. These are the same molecules already naturally present in the sea, which regulate its chemical balance — which is why the system does not alter the ecosystem, but rebalances it. In this way, CO₂ is stored in stable form for over 10,000 years, while at the same time contributing to increasing the alkalinity of the water and locally countering acidification.
In September 2024, Limenet launched in Augusta, Sicily, what it presents as the world's first industrial plant dedicated to marine carbon dioxide sequestration, also issuing the first blockchain-certified carbon credits linked to this technology. A solution that sits within the still-open scientific debate on the role of carbon dioxide removal technologies (the so-called Carbon Dioxide Removal) in achieving climate targets.
Protecting the oceans also means intervening well before the coastline: it is from this insight that Blue Eco Line was born, an Italian startup that develops technologies to intercept and monitor plastic waste in rivers, before it is carried out to sea.
The main solution, River Cleaner, is a highly automated system positioned along riverbanks: using an image recognition system based on artificial intelligence, it identifies floating waste, extracts it from the water and transports it to collection bins, from where it can then be sent for disposal.
Alongside this operational system, Blue Eco Line has developed River Eye, a monitoring system that uses high-resolution cameras and neural networks to identify and classify floating waste, providing public bodies and river basin managers with data to map the most critical areas and plan targeted interventions. An important shift in perspective: the sea is not protected only by cleaning beaches or collecting plastic on the open ocean, but by acting upstream, connecting cities, territories and oceans in a single system.
