The Hong Kong startup combines 3D-printed reef tiles, biodiversity monitoring and long-term data to help companies manage their impact on marine ecosystems.
Updated
August 7, 2026 4:10 AM
Young corals growing on Archireef's 3D-printed terracotta reef tiles beneath the sea. IMAGE: ARCHIREFF
Anyone who has snorkeled over a coral reef has probably admired its vibrant colours and the marine life swimming between its branches. What is less visible is how easily these ecosystems can be damaged. Rising ocean temperatures and pollution continue to put reefs under pressure, while coastal development creates another threat. Construction can stir up sediment that settles on corals, blocking the sunlight they need and making it harder for damaged reefs to recover.
Protecting marine ecosystems is becoming a shared responsibility. Alongside scientists, governments and conservation groups, businesses whose operations affect the ocean are increasingly expected to understand, manage and reduce their environmental impact. They must also show regulators, banks and investors that they are meeting their environmental commitments.
Archireef helps businesses meet those demands. Founded by Vriko Yu, the Hong Kong-rooted B2B startup specializes in marine ecosystem restoration and ocean nature risk management. Drawing on years of research at the University of Hong Kong, Yu built the company to help organisations understand, measure and reduce their impact on marine ecosystems.
Yu describes Archireef as an “end-to-end ocean nature risk management company”.
“What we offer them is a credible way to meet those obligations and stand behind the results,” she says.
One of the company’s main tools for restoring damaged marine ecosystems is its flagship 3D-printed terracotta reef tile. The tiles provide a stable foundation where young corals can attach, grow and survive over time.
Archireef chose terracotta instead of concrete and other conventional materials because it is pH-neutral and does not release harmful chemicals into the water. Its surface also gives corals a suitable place to attach naturally.
Before placing a single tile in the ocean, the team studies the proposed restoration site to determine whether recovery is possible. It assesses the water quality, biodiversity and general health of the ecosystem. As Yu explains, restoration should begin only where nature has a realistic chance to recover.
“Restoration isn’t about replacing nature or engineering a reef into existence. It is about removing the barriers and giving a degraded system the conditions it needs to begin recovering on its own”, she says.
Once the team selects a site, divers carefully place the tiles on the seabed. Their curves, ridges and crevices imitate the structure of a natural coral reef, creating sheltered spaces for marine species. The design also helps limit sediment build-up, which can block sunlight and smother young corals.
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Archireef adjusts the shape of its reef tiles for each project.
“There’s no universal reef, so there’s no universal tile”, Yu says.
Instead of producing one standard model, the company adapts each design to the coral species, water conditions and surrounding marine environment. A coral restoration project in Hong Kong may therefore require a different tile from one in Saudi Arabia, even when the same manufacturing process is used.
“The biggest adaptation from site to site is usually the match between design, species and environment, not the manufacturing itself ”, Yu explains.
Although the reef tile is Archireef’s most recognizable innovation, Yu sees it as one part of a much broader service.
“The reef tile gets the attention because it’s tangible,” she says. “But the real product is the proof — defensible, audit-ready evidence of nature recovery that an organization can put in a disclosure and stand behind under scrutiny”.
Producing that evidence requires years of biodiversity monitoring. Long after the reef tiles have been installed, Archireef continues to track coral survival and the health of the surrounding marine ecosystem. Its monitoring methods include ecological surveys, AI-assisted species recognition, photogrammetry and environmental DNA testing.
Photogrammetry uses photographs to produce detailed 3D models of the reef. These models allow the team to measure changes in coral growth and reef structure over time.
Environmental DNA, commonly known as eDNA, offers another way to monitor marine biodiversity. Traditional ecological surveys often depend on divers recording the species they can see. eDNA testing instead examines traces of genetic material left in the water by marine organisms, including skin cells, mucus and waste.
By analyzing these traces, Archireef can detect species that may be hidden, difficult to identify or absent during a dive. This gives the company a more complete picture of the ecosystem and how it is changing.
For Archireef, the success of a coral reef restoration project is determined by what happens several years after installation.
“The indicators that matter aren’t the ones that look good on deployment day”, Yu says. “They’re the ones that show, two, three and five years on, whether a genuine ecosystem is establishing and sustaining itself”.
At the company’s first restoration site in Hoi Ha Wan, Hong Kong, around 90% of the transplanted corals remained alive four years after deployment. The long-term survival rate suggests that the ecosystem is recovering rather than simply appearing healthy during the early stages of the project.
Results like these have helped Archireef move beyond academic research and secure collaborations across the public and private sectors. In Hong Kong, the company has worked with government departments and public organisations responsible for coastal infrastructure and marine conservation.
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An interview with Tengin founder Madhu on turning coconuts into a business built around farmers, villages and communities.
Updated
August 7, 2026 4:12 AM
Workers of Tengin. PHOTO: TENGIN
In Southern India, coconuts are part of daily life. They are used in food, rituals, farming and home remedies. For Tengin, a social startup whose name means “coconut” in Kannada—a South Indian language—the crop also offers a way to build a rural business with deeper local impact.
Founded by Madhu Kargunda in 2017, Tengin works with farmers, artisans and women’s collectives in Karnataka to make products from almost every part of the coconut. Its range includes virgin coconut oil, desiccated coconut powder, shell-based handicrafts, candles, home décor items and other coconut-based goods.
The larger idea is simple. Farmers should play a bigger role in the value created from the crops they grow. Tengin is trying to help rural communities move beyond supplying raw produce and take part in processing, branding, packaging and sales.
Madhu grew up in an agricultural family. Over the years, he saw many young people move away from farming to look for stable jobs in cities. To him, the problem was not farming itself. The bigger issue was that farmers often missed out on the value created after crops left the farm.
A coconut might be grown in a village, but much of the income comes later through processing, branding and retail. That gap stayed with him, eventually leading him to leave his eight-year career in IT and return to agriculture full-time.
Started with just making virgin coconut oil, Tengin has grown into a wider coconut products business. The startup is now working with around 15 to 20 farmers and artisan groups across Karnataka. It is also building production capacity for larger retail and B2B partnerships.
Today, Tengin generates annual revenue of roughly ₹50-60 lakh, or around US$52,000 to US$62,000. It has also started testing international demand, including a recent export of around 200 kilograms of desiccated coconut powder to Texas.
As Tengin expanded, the team began looking more closely at parts of the coconut that were usually treated as waste or low-value byproducts, such as coconut shells and coir. At first, Tengin treated them that way too.
“When we started, we used to burn some of the shells”, Madhu said. “Later, we realized it was an economic opportunity”.
That changed the company’s product strategy. Local artisans working with Tengin now are turning coconut shells into bowls, incense holders, candles, coffee mugs, mobile stands and handcrafted décor items.
This gives Tengin a place in the circular economy, where waste materials are reused instead of thrown away. For Madhu, though, sustainability has to do more than reduce waste. It should also create income in the community.
“We wanted to minimize waste and maximize wealth locally”, he said.
Tengin does not depend only on one central factory. Instead, it works with smaller village-level production groups that connect to a larger business network. This helps farmers stay close to their land while also taking part in processing and manufacturing. It also creates local jobs, which can reduce the pressure to migrate to cities.
Yet, the model is not always easy. In the early days, Tengin had to convince some farmers to move from chemical farming to natural farming. Moreover, the weather has also become harder to predict. Irregular rainfall and changing harvest cycles can affect coconut prices and production consistency.
Still, Madhu sees the village-based model as central to Tengin’s identity. For him, villages are living systems built on shared work, local knowledge and interdependence.
“The definition of a village is inclusiveness”, he said.
That belief also shaped Tengin’s “coco tourism” initiative. Through the program, visitors meet farmers, learn about farming practices and see how coconut products are made.
During one visit by MBA students from Indiana State University, an unexpected spell of rain gave the group a closer look at village life. Farmers gathered and began singing traditional folk songs to express gratitude to nature. For the students, it became a lesson in culture as much as business.
Madhu sees these moments as part of what rural entrepreneurship can protect.
“If villages become empty, we lose language, traditions and local knowledge too”, he said.
Tengin’s model is not difficult to copy on paper. Madhu is open about that.
“Anyone can do it”, he said, “but what matters is how you work with people”.
For him, the harder part is building long-term trust with farming communities. Tengin works through relationships more than rigid contracts. This encourages farmers and local groups to participate in the system in a more collaborative way.
That trust has become one of the startup’s strongest assets. It shapes how Tengin works with producers and how it presents its products to customers.
For Madhu, it is not enough to call a product sustainable. Customers should be able to understand where it came from, who made it and how their purchase supports the people behind it.
That matters even more in a market where terms like “eco-friendly” and “organic” have become buzzwords. Madhu knows that these words can feel empty when brands do not show what they actually mean.
“Anyone can use these words today,” he said. “What matters is whether consumers can actually see what you are doing”.
This is why Tengin focuses on transparency and storytelling. The startup wants customers to see the full journey of each coconut product, from the farm to the finished item. It also wants them to understand whose livelihood is connected to that journey.
Madhu also believes small brands cannot depend on products alone. Products can be copied, but a clear story, a trusted community and a visible impact are harder to replicate.
“Don’t try to sell only the product,” he said. “When you try to sell the product, you are being sold once”.
Each Tengin product includes details about the people behind it and how profits are shared. In that way, the company connects its coconut products to the farmers, artisans and village systems that make them possible.
For Madhu, entrepreneurship starts with the problem. Founders, he believes, should understand the problem deeply before thinking about scale and revenue.
“An entrepreneur is someone trying to solve an existing problem”, he said. “Sometimes it may be a small problem, sometimes a niche one. It could be in technology, energy, farming or any other sector—but first understand what problem you are trying to solve”.
Farming has also taught him patience. He gives the example of coffee.
“When you plant coffee, you know it may take five years before you see results”, he said, “but you still [have to] water it every day”.
He sees entrepreneurship the same way. Building systems, communities and trust takes time. Growth may be slow at first, but daily work matters.
Adaptability is another lesson he returns to often. Farming conditions change constantly, and so do markets. In both cases, people have to keep learning, unlearning and adjusting.
“Entrepreneurship is about constantly learning new things because the world is changing all the time”, he said. “You need to stay relevant, understand what connects with [your customers] and adapt accordingly”.
Looking ahead, Tengin plans to grow its farmer network, strengthen production capacity and expand its export business. Madhu is also looking to collaborate with more platforms, storytellers and communities that can help amplify the voices behind the products.
The startup is also involved in rural community initiatives, including support for government schools and menstrual health awareness programs.
For Madhu, giving back is part of how he defines success. With more resources, he would invest further in farmer education, village-level production systems and community development.
By building a business around coconuts, Tengin is also making a larger case for rural entrepreneurship. Its work shows that a modern consumer brand can grow without losing its connection to the farmers, traditions and village ecosystems that make that growth possible. For Madhu, that is the real measure of progress: creating value that stays rooted in the community.