Bye, kale: Marine scientists want you to eat more seaweed

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Move aside, kale, because it’s seaweed’s turn to be the hot, nutritious green. After all, it’s extremely nutritionally dense, a regenerative crop, only needs sunlight and sea water to grow, and is just as versatile—if not more so—than the leafy greens in the typical American produce aisle. Which is why Alanna Kieffer is advocating for it to be the next big thing in ocean-to-plate dining in the United States. (Of course it’s worth noting that seaweed is already a diet staple in many East Asian countries dating back thousands of years.)

Kieffer, a marine biologist, manages Oregon Seaweed—the largest land-based operation in the country—in Garibaldi, Oregon, a small fishing town on the coast west of Portland that’s better known as the home of Tillamook Creamery than ocean vegetables. She also founded education company Shifting Tides to offer tours and workshops on ocean foraging and marine science. Between the two companies, one could argue the town deserves to be as synonymous with ocean vegetables as ice cream.

Nutritious and delicious

After all, seaweed—in all its many forms, from kelp to dulse and everything in between—is essentially a superfood. In fact, the red Pacific dulse she helps cultivate contains all the necessary amino acids, is a great source of several vitamins and minerals, including potassium, calcium, iron, vitamins A and C, and contains fiber, iodine and omega-3s. It’s even made up of about 30 percent protein, according to Kieffer.

[Related: Europeans ate a lot more seaweed 8,000 years ago]

What’s more, it requires very little to flourish. “It really seems like it grows itself,” Kieffer explains. That’s because dulse is a clonal species, meaning it’s constantly fragmenting and cloning itself. It doesn’t even need a solid surface in which to plant roots. All it takes is sea water, light, and a few simple technologies to help the process along.

No green thumb required

In the case of Pacific dulse, it starts with a few loose plants placed into the 20 1,500-gallon tanks at Oregon Seaweed, each of which are supplied nutrient-dense seawater by pipes that extend into the bay. At high tide, a switch on the nearby pier flips on and water is pumped into the tanks while bubblers circulate the contents, forcing the seaweed in a tumbling motion as it rotates from top to bottom over and over. This allows the seaweed to move around the tank so every spindly clump of rust-red plant gets access to sunlight. 

large white tanks filled with water and seaweed on coast
The tanks at Oregon Seaweed on Oregon coast. Image: Courtesy of Oregon Seaweed

The bubbler slows or speeds depending on the season and the dulse gets harvested as the tanks fill to a max of 400 pounds of seaweed. When it is, a few plants are left inside to allow the process to continue.

The harvested seaweed is then sun-dried, which requires no energy at all, and is sold fresh or dried for an impressive amount of applications and edible options. Other seaweed operations may operate a bit differently depending on whether they are land-based or ocean-based and what type of seaweed is being grown—kelp is more often grown on lines placed in the ocean–but all tend to be simple and require little if any careful tending or intervention.

Sustainable superfood

That simplicity is part of what makes ocean vegetables such a sustainable crop: Seaweed farming doesn’t require pesticides or fresh water, just sunlight and sea water. And Oregon Seaweed’s operation utilizes a fraction of the energy required for other agricultural products, Kieffer states.

Seaweed is also a powerhouse when it comes to capturing and sequestering carbon. That’s due in part to it being one of the fastest-growing photosynthetic organisms on the planet—some seaweed can grow up to three feet per day, Kieffer says. Though Pacific dulse sees something closer to a two to three percent daily growth rate. And since photosynthesis is the process by which carbon is captured, it makes seaweed impressively effective at sequestering it.

For example, according to one expert, a single tree can absorb an average of 22 pounds of CO2 per year (depending on its age and species) while dulse sequesters one pound for every four grown.

That said, calculating seaweed as a carbon sink is more complicated than studying trees that live for hundreds of years, and more study is required to find out what happens to that carbon when seaweed is harvested and consumed. When trees die, some of the carbon they’ve collected returns to the atmosphere as they decompose on the forest floor. What happens when seaweed is harvested is still largely a mystery.

However, there is some research being conducted on seaweed afforestation, or planting permanent seaweed gardens that are not intended to be harvested and eaten, which research suggests could be effective at sequestering more carbon for the long term.

But the plants also reduce ocean acidification, which can have harmful impacts on all aquatic life. Seaweed absorbs the excess nitrogen and carbon that causes acidification (and often comes from agricultural runoff), creating more healthy and balanced ecosystems.

That includes for us land-dwellers, people and animals alike. In fact, one study showed that when seaweed was fed to cows as a small part of their overall diet, it helped with digestion and reduced methane emissions by an astonishing 80 percent.

Of course, the long-term sustainability of seaweed farms is still being researched. For example, scientists are discovering that it should be grown away from seagrass beds so it doesn’t block light to already established ocean ecosystems. Entanglement could also be an issue–if a minor one–for aquatic life in off-shore farms. And while responsible farms should stick to endemic species of the plants already found locally, seaweed farming offers many people who fish for a living a source of income in the off-season and provides a practically endless supply of sustenance and supply for a growing population. Yes, in addition to being used as fertilizer, bio fuel, textiles, even a cat food ingredient, seaweed is a delicious and versatile ingredient in the kitchen.

Eat up

“I’m obsessed with dulse for its versatility,” Kieffer says. “It’s a really easy ingredient to incorporate into things.” She calls it the kale of the sea: you can sauté it, oven roast it, make a seasoning out of it, pickle it, dehydrate it, and much more. Seaweeds bring flavor, texture, and added nutrients to almost any dish, but it’s just as delicious on its own. Cooked, it lends a smoky umami flavor, you can use it instead of anchovies to make a vegetarian Caesar dressing, and when ground, it can be used as a more nutritious salt alternative.

Sneak it into pasta, make a dulse onion jam or chop up a fresh batch and use it to top a few slices of bruschetta. The possibilities are practically endless, as evidenced by not only Oregon Seaweed’s recipe page, but by Winter Waters, a month-long state-wide dining series Kieffer co-founded to connect Oregon chefs to seaweed distributors, encourage creativity in commercial kitchens, and get more seaweed on Americans’ plates.

It’s simply a matter of educating people, she says, showing them how delicious seaweed can be, what a sustainable crop it is, and inspiring folks outside of places where seaweed is already a food staple to broaden their culinary perspectives.

Alisha McDarris Avatar

Alisha McDarris

Contributor, DIY

Alisha McDarris is a DIY contributor at Popular Science. She’s a travel lover and true outdoor enthusiast who enjoys showing friends, family, heck, even strangers, how to stay safe out there and enjoy more time in the wild. When she’s not writing, you’ll find her backpacking, kayaking, rock climbing, or road tripping.