How a British scientist saved the Japanese nori industry from total collapse

Food & Drink · Published 3 October 2026 Swipe more like this →

In short: Nori was once a wild-harvested luxury, but after World War II, the industry faced a crisis. Production plummeted until scientists discovered the secret to its complex life cycle in the work of a British phycologist. Today, she is revered in Japan as the Mother of the Sea.

Nori, primarily derived from the red algae genus Pyropia, has been a staple of Japanese culture since at least the 700s. Originally, the term was generic, covering various seaweeds used for everything from tax payments to shrine offerings. For centuries, it was consumed as a paste, but around 1750, the invention of a shredding and rack-drying method in Asakusa transformed it into the thin, paper-like sheets we recognize today.

The industry's modern survival is a testament to scientific collaboration. Following World War II, wild harvesting could not meet Japan's food demands, and artificial cultivation efforts were failing because farmers did not understand the seaweed's three-stage life cycle. The breakthrough came from the research of Kathleen Mary Drew-Baker, a British phycologist who studied Porphyra umbilicalis in Wales. Her findings allowed Japanese scientists to master artificial seeding, effectively rescuing the industry. Her legacy remains so profound that a statue stands in her honor in Japan.

Today, nori production is a sophisticated agricultural enterprise, with over 600 square kilometers of coastal waters dedicated to the crop. While the process is highly automated, it still relies on the same biological principles. However, the industry faces new pressures, including increased competition from China and Korea, and ongoing debates regarding the nutritional profile of the seaweed. While some studies suggest nori could serve as a source of vitamin B12 for vegetarians, other research indicates that processing and storage may render this B12 inactive or unusable by the human body.

Beyond its culinary versatility, nori is a complex product that requires careful handling. Because the dried sheets are highly hygroscopic, they degrade quickly if exposed to moisture, necessitating the use of desiccants for storage. Consumers should also be aware that nori can harbor allergens similar to those found in crustaceans and may contain trace amounts of heavy metals like arsenic and cadmium, depending on the environment where it was harvested.

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