In another EarthDate, we talked about kelp: 100-foot-tall seaweed that grows near shore.

Asian cultures have farmed kelp and other large seaweeds for centuries. If you’ve had Japanese food, you’ve probably eaten it sliced in seaweed salad, dried to flavor soup, or wrapped around sushi.

Seaweed is nutritious, easy to grow and harvest, and requires no irrigation or fertilizer.

It thrives in cool- and cold-water bays, including those that have become barren from overfishing, mismanagement, or agricultural runoff.

These many qualities have encouraged a new generation of seaweed farmers, often former commercial fisherman. They’re creating new vertical seaweed farms in places like the North Atlantic and the Pacific Northwest.

Farmers attach seaweed spores to ropes, then anchor them to the bottom. As the seaweed grows, it takes in carbon dioxide and recharges the water with oxygen, making it ideal for mollusks.

So farmers also grow oysters, scallops, and mussels with the seaweed. Each acre of vertical farm can produce up to 10 tons of kelp and a quarter million bivalves per year.

Researchers have calculated that farming an area the size of Washington state could produce all the food the worlds’ human population needs.

Of course, few of us would want to eat just kelp and oysters. But vertical ocean farms can employ out-of-work fisherman and revitalize ocean environments, all while producing food—a sustainable aquaculture that’s a win-win all the way around.