Combating Global Warming with "Blue Carbon": The Potential of the Artificial Reef "Reef Ball" (Part 2)

As global warming accelerates, "blue carbon" is gaining attention as a decarbonization initiative. Among these, the artificial reef "Reef Ball," developed in the United States, is expected to have a significant impact on preserving marine ecosystems.

This time, we held a discussion between Mr. Osamu Ikeda, President of Asahi Tech Co ., Ltd., which is promoting Reef Ball adoption in Japan, and Mr. Takashi Fuji of Dentsu Inc., who works in the carbon neutrality and blue carbon fields. In Part 2, we hear about improvements to Reef Ball and Asahi Tech's future outlook. We also bring you a report from Asahi Tech's headquarters factory.

Preventing "Ocean Desertification" Through Reef Ball Improvements

Fuji: Mr. Ikeda's challenge began in his hometown of Nagasaki City, with technical support from the U.S.-based Reef Ball Foundation. How did you then proceed to promote and develop the Reef Ball?

Ikeda: The American Reef Ball was originally developed for coral reef conservation and cultivation. Meanwhile, the problem occurring in many areas of Japan, including Nagasaki, is the disappearance of seaweed, known as "seaweed die-off." Seaweed die-off has stages. The state commonly referred to as "seaweed die-off" occurs when sea temperatures rise, leading to an increase in organisms like sea urchins that devour the seaweed. In this state, seaweed can actually still regenerate. However, if this continues, "calcareous algae" begin to cover the seabed. I refer to this advanced stage of severe isoyake as "marine desertification." Once this occurs, seaweed regeneration becomes impossible. Even if sea urchins increase and are extensively harvested, the seaweed will not return.

Ikeda: How can we prevent this? Through extensive research and consultations with many experts, we arrived at "ferric fulvic acid." Originally, leaves and branches falling to the forest floor are decomposed by microorganisms, producing "fulvic acid." Ferric fulvic acid is formed when this fulvic acid binds with iron in leaf mold. This substance flows from rivers into the sea, where it serves as a nutrient for seaweed while also suppressing the growth of calcareous algae. It is thought that while nutrients from the satoyama once flowed steadily into the sea, various forms of environmental destruction have prevented them from reaching the ocean, leading to a steady decline in seaweed beds.

Therefore, I successfully developed a technique to improve Leaf Balls by incorporating fulvic acid iron into them. This allows Leaf Balls, simply placed in the ocean, to gradually release fulvic acid iron into the sea over a period of 10 years. In other words, by having Leaf Balls—packed with vital nutrients for seaweed—firmly anchored on the seabed, numerous seaweeds can regenerate from them. As the spores of these seaweeds spread throughout the ocean, the seaweed beds can be restored. These technologies were patented in 2023 and an international patent application was filed.

Realizing "seaweed pastures" for broader area restoration

Fuji: So, you took the Leaf Ball originally developed in the US, made further improvements, and evolved it into something optimal for Japanese seaweed bed restoration. Are you actually seeing results?

Ikeda: We began full-scale demonstration experiments in 2019. In nearly all areas where Leaf Balls were installed, seaweed has grown robustly. While other seagrass restoration technologies exist, it's very common for seaweed to grow in the first year but not in subsequent years. However, our Leaf Balls have proven capable of sustaining robust seaweed growth beyond the first year.

Fuji: I believe Leaf Ball technology has tremendous potential. I want to do what I can, however small, to help spread its use even further.

Ikeda: Currently, with the cooperation of various fishing cooperatives, we are gradually expanding the installation sites. We want as many people as possible to learn about Reef Balls and definitely use them.

In 2022, the Leaf Ball algal reef was certified under Nagasaki City's "Excellent Product Certification System." We have also applied to the Ministry of Land, Infrastructure, Transport and Tourism's "New Technology Information System (NETIS)," established to share and provide information on new technologies for their utilization. We believe that once people learn about our technology, they will surely find it interesting. We also actively promote marine education for the next generation by conducting workshops with children.

Our next major challenge is developing "seaweed ranches." We plan to enclose specific areas, such as unused harbors, install Reef Balls there, and regenerate seagrass beds. Simultaneously, we will cultivate abalone, turban shells, sea urchins, and other marine life that thrive in these beds. This allows for stable harvesting of seafood. Furthermore, as seaweed spores disperse from these farms into the open ocean, it contributes to seagrass bed restoration across broader areas. We will continue striving to realize such seaweed farms.

"We want to restore seaweed beds across various regions" – Asahi Tech's diverse challenges

After this interview, we visited Asahi Tech's headquarters factory to see the production of Leaf Balls and the experiments conducted there. Leaf Balls come in various sizes to ensure the optimal one can be installed based on ocean conditions. Using molds also allows for the creation of original Leaf Balls. "We run programs like workshops for children where everyone makes their own unique Leaf Ball," Mr. Ikeda shared. "Making it yourself fosters a deeper attachment and seems to increase interest in the ocean."

Furthermore, Mr. Ikeda was developing products beyond Leaf Balls. "The fulvic acid iron mixed into Leaf Balls is also mixed into these small blocks. Simply scattering these blocks in the ocean creates a state where nutrients for algae gradually dissolve into the sea. It's like feeding fish – you can easily spread nutrients into the ocean. In areas with solid rocky foundations, you can regenerate seaweed beds using just these blocks, without needing Leaf Balls."

Behind the factory, many Leaf Balls await shipment. "Things don't always go as planned, but still, more and more people are gradually becoming interested in Leaf Balls. We're now conducting experiments not only in Nagasaki and the Kyushu region but also in Hokkaido. The bottom line is, if you install these, the seaweed beds will definitely regenerate. I really want many more people to join us," Mr. Ikeda passionately shared.

Mr. Ikeda, who fuses Japanese and American technologies to evolve Leaf Ball. He will continue his challenge to solve the major social issue of global warming.

Next time, we bring you a conversation between Hisanori Tayama, representative of the general incorporated association "Marine Habitat Iki," which is installing Leaf Balls in Iki City, Nagasaki Prefecture, and Takashi Fuji of Dentsu Inc.

*This refers to an international application under the Patent Cooperation Treaty (PCT), a system where filing a single application grants patent rights in all 157 PCT member countries for a specified period.