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Wild seaweed can grow in warm or cold ocean waters. This mix of kelp, Irish moss, and sea lettuce was harvested off the coast of Maine.

This Seaweed Is Good for You—And for the Environment

Kelp’s flavor may not please every palate, but its ability to suck up carbon dioxide could help protect the ocean.

This story appears in the November 2017 issue of National Geographic magazine.

Name the last place where you saw seaweed on the menu, not including a Japanese restaurant. Drawing a blank? That may be because, outside of Japan and other parts of Asia, seaweed’s unique flavor and mouthfeel have not been widely embraced.

These marine plants and algae are sometimes called “sea vegetables”—but there are reasons beyond gastronomy to appreciate them. Kelp, in particular, has the potential to greatly reduce ocean acidification. Naturally occurring in cold, coastal marine waters, kelp grows quickly without the need for fertilizer, and it takes up carbon dioxide—which can exacerbate climate change—as well as excess nitrogen and phosphorus. The problem, though, is that there’s not enough of it.

Enter kelp farming. China currently leads the industry, having produced more than seven million metric tons in 2015, says University of British Columbia marine ecologist Muhammed Oyinlola. Kelp farms have also been in operation for centuries in Japan and Korea.

If seaweed farming expands, Oyinlola says, it “could remove billions of metric tons of carbon dioxide from the atmosphere.” And more kelp aquaculture could yield more biodiversity: In California alone, researchers have found that wild kelp “forests” can shelter more than 800 species of marine life.

Kelp and other algae are high in minerals and fiber and have gelling properties. Those traits have led to their use in cosmetic products and vitamins and as feed for farmed fish and livestock. Meanwhile, look for them as a fresh, sustainable food on ever more plates.

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