What he’s looking for: kelp blades streaked with sorus tissue, a dark band teeming with millions of spores. A wiry man in his 60s, Lindell has developed relationships with homeowners and researchers across hundreds of miles of New England’s coast so he can access the kelp integral to his work—and, potentially, to the future of seaweed farming in the United States.

After several dives, Lindell has filled his mesh collection bag with cuttings and swims to shore. He stores the prized tissue in a cooler to keep it damp and cool for the five-hour drive, and then sets off for his laboratory at Woods Hole Oceanographic Institution in Massachusetts. Here, over the next 45 days, the spores will be carefully cultivated into seed for farmers and scientists to outplant in the ocean.

Every year, every ounce of any kelp variety farmed commercially in the U.S.—now approaching millions of tons—begins with this process. Many growers see it as a bottleneck: Propagation from wild-harvested seaweed is costly, lengthy, and ties rural coastal communities to laboratories that are often hours, if not days, away. It also shortens the seaweed growing season, as sorus tissue can only be harvested for a few months of the year. And, most frustrating to farmers, relying on wild stocks for farmed kelp means that growers have very little control over the final product. What could look underwater like a yummy blade may turn out to be a varietal better suited to feeding snails than pleasing the human palate.

Lindell’s eponymous lab at Woods Hole may look humble, with low ceilings and cement floors, but it’s meticulously organized, with hundreds of seaweed varietals catalogued and floating in refrigerated containers. As ferry horns punctuate the rushing sound of seawater piped into scores of tanks, a team of scientists toils away at an ambitious project: revolutionizing kelp propagation. They have just mapped a single sugar kelp genome for the first time, and the results are about to be publicized through the Joint Genome Institute in Berkeley, California. Next, they plan to map a genome for the entire species. The project is supported by a $5.9 million grant from the U.S. Department of Energy MARINER program, part of more than $66 million that the agency has invested in American seaweed production since 2018.

If successful, their work will put Americans at the front of seaweed science globally, making it possible for laboratories like theirs to select wild kelp with ideal traits and create new kelp “seeds” in two weeks. This breakthrough in selective breeding would be the biggest advance in mariculture in the past hundred years, akin to Punnett’s Square, which revolutionized plant breeding in the early 1900s.

A Keystone Species in Decline

Different varieties of kelp have thrived in the world’s oceans for more than 100 million years, along the equator and up toward the poles. In 2023, scientists estimated that kelp forests suck up about a third of the world’s atmospheric carbon; kelp also supports fisheries and removes nitrogen pollution. Together, these benefits are valued at as much as $500 billion annually.

Now, this complex, ancient species is in jeopardy. Globally, kelp forests are receding at a rate of 1.8 percent a year, due in part to climate change and human impact. In 15 years, marine scientists say there may not be enough wild stock for farmers to rely on, especially in states like Maine, where kelp forests are rapidly declining. On the West Coast, kelp loss has been even more extreme, with 96 percent of forests from San Francisco to northern Oregon dying off over the past decade, according to The Nature Conservancy. Beginning in 2013, a series of cascading events wreaked havoc: First, a massive heat wave plunged the kelp into stressed conditions at the same time that purple sea urchins—which feed on kelp—lost their biggest predator, the sunflower sea star. Without sea stars to keep them in check, the urchins multiplied and, in a behavioral shift, left their customary nooks and crannies and began devouring the kelp forests.

Scientists believe Lindell’s work could help save the future of seaweed. By mapping sugar kelp, Lindell is creating a Rosetta Stone of kelp traits and corresponding DNA that can then be used by researchers globally to better understand, and protect, their wild kelp populations.

For example, for a kelp forest stressed by increasingly warmer waters, conservationists could identify and plant strains of kelp that are more heat tolerant. Tristin Anoush McHugh, kelp project director at The Nature Conservancy, monitors California’s remaining forests regularly, and believes that Lindell’s advances in seaweed reproductive technology could bolster restoration efforts. Scientists could isolate kelp that survive mass die-off events, propagate them in the lab, and then plant them in the open ocean, creating kelp refuges. “We can’t go and remediate 350 kilometers of coastline, but we can certainly create oases along the way,” she says.

A Market Worth Millions

For decades, China has led the industry, valued at $643.4 million in 2022, a slice of the larger $5.6 billion global seaweed market. According to the U.N.’s Food and Agriculture Organization, China produces 89 percent of the world’s farmed kelp; the U.S. produces less than .01 percent—what one hatchery specialist in Maine calls a “rounding error.”

Many kelp companies in the U.S. cite America’s small appetite for seaweed as an impediment, especially compared to Asia, where seaweed is consumed regularly and in many forms. But minimal demand is only one reason for the low market share. The high cost of farming is another.

American farmers can expect to pay about $1 a foot for string inoculated with kelp seed. The yield is an average of 4 pounds of mature kelp per foot, which nets about 50 cents a pound, according to Lindell. “I don’t know any other agricultural or aquaculture industry where the cost of seed can be as much as 50 percent of the farmer’s revenue,” he says with a scoff.

Compared to other seaweed-farming countries, America is an outlier. Korean seed string is sold for 5 cents a foot and yields 30 pounds per foot, according to Jang K. Kim, a professor in the department of marine science at Incheon National University in South Korea. In China, the seed string cost-to-yield ratio is similar, because the government subsidizes that industry, according to scientists there.

Selectively Bred Spores, on Demand

When the sorus tissue is clean, Lindell’s scientists dry it overnight and then immerse it again in sterile seawater, prompting the tissue to release its spores. These develop into gametophytes—tiny, feathery clumps, male and female—that are selected for desired traits and then bred to create zygotes (fertilized eggs) that develop into kelp seed (or, technically, juvenile sporophytes). Using gametophytes for seed instead of wild-harvested sorus tissue would greatly decrease the costs, since using gametophytes requires no sanitizing and they can be bred for multiple seasons.

“[Gametophytes] allow us to do what animal breeders and plants have been doing for millennia now—make a single-pair cross that we can then ascertain some value to,” explains Lindell. “We can measure—how long is that blade? How sweet is it? Does it resist high temperature?”

Every harvest season for the past five years, his lab has measured these crosses for 30 to 50 traits, creating a tremendous amount of information for breeding commercially attractive future generations—and for potentially restoring wild kelp one day. The lab publishes all of its breeding information on Sugar Kelp Base, an open-source website for global seaweed researchers.

In Asia, selective breeding is common in mariculture, and is why yields can be four to six times larger than on American farms. But in recent years, Asia’s yields have flatlined, possibly due to a lack of genetic diversity after 50 generations of breeding the same genetic lines of kelp.

Instead, Lindell’s genomic selection approach allows his team to conserve genetic diversity while still selecting for specific traits. They’ve also worked closely with Cornell University and the U.S. Department of Agriculture, borrowing crossbreeding techniques from terrestrial agriculture. “In the last five years, we’ve been able to make achievements that took the Asian countries 30 or 40 years to accomplish,” says Lindell.

What is the No. 1 thing they’re breeding for? “Yield. And No. 2 is yield. And No. 3 is probably yield,” says Lindell, laughing. “Every farmer’s business plan and projections are based on yield. Every 10 percent improvement in yield produces probably a 5 percent improvement in their bottom line.”

Increasing yield is part of the focus of the MARINER grant. Currently, the average U.S. farm yield is about 4 pounds per foot. So far, Lindell’s team has been able to triple that yield on average, with hopes of isolating a strain that can produce 25 pounds per foot, approaching the yields of China and South Korea. Lindell is also looking at kelp traits like a strong umami flavor, or thicker blades that make them easier to use as wraps for food, or an ability to resist predation by other marine organisms.

Creating gametophytes, says Lindell, allows seaweed farmers to become “the orchestrator of your own symphony when it comes to the seaweed planting season. You could start it as early or as late as you choose.” Growers would be able to time their own planting, instead of waiting for wild kelp to mature and produce sorus tissue—and they would have a longer growing season and therefore a larger yield.

Gametophytes also mean less nursery time. Currently, beginning with wild-harvested sorus tissue requires around 50 days to produce kelp “strings”—strings of kelp seeds grown out in a nursery until ready to deploy on a farm. With gametophytes, that time is cut to around 30 days. Additionally, farmers can choose varietals based on their traits, similar to the way apple growers select for flavor, color, juiciness, or other qualities.

The Near Future of Seaweed Farming

Except for the warming waters. The Gulf of Maine is warming 99 percent faster than the rest of the ocean, with devastating repercussions for all marine life, from kelp to finfish to lobster. “It’s harder and harder to find reproductive kelp in September to have ready by, say, Halloween,” says Thew Suskiewicz, a seaweed scientist at Maine’s Atlantic Sea Farms, the largest seaweed aquaculture operation in the country. The company provides seed to partner farmers to outplant. For the 2023-2024 season, Atlantic Sea Farms pulled in a record-breaking 1.3 million pounds of kelp for its line of foods.

Suskiewicz operates the farm’s hatchery after a career of studying algae, including at the seaweed food company Monterey Bay Seaweeds. “I’ve been looking at how kelp assemblages have changed in the Gulf of Maine in the last 30 years—and we’ve seen profound changes. Most of the species here have some life stage that is very dependent on the kelp,” he says, noting lobster as an important example. Lobstering is a nearly $400 million annual industry in Maine alone, according to NOAA. Wild kelp’s decline, he predicts, “is going to have a lot of cascading effects.”

Many of Maine’s lobstermen and commercial fishers are already experiencing huge shifts in the marine populations they harvest. That has led some to get into the farmed seaweed industry to diversify their incomes and businesses in the face of warming waters. Establishing gametophyte cultures would make kelp seed string cheaper, offer more predictability, and make kelp farming less dependent on wild kelp beds. Suskiewicz is working closely with Lindell’s lab, and next season will begin raising gametophyte-spawned kelp in Maine’s waters.

“Next year will be the first year we put them out, and we’ll just measure performance—including, how much did they grow? How do they taste? What is their blade length?” says Suskiewicz.

Suskiewicz believes that the American seaweed industry is at an inflection point, and that selective breeding is arriving at the perfect time. Five years ago, Atlantic Sea Farms seaweed salads were available only in specialty food stores. Now, they’re found across the country, thanks in part to the company’s intensive marketing efforts to introduce the average American to kelp.

Now that seaweed is a bit more familiar, Suskiewicz believes that if the cost of kelp seed drops through widespread adoption of gametophytes, the industry will be able to scale up and finally compete with Asia. “People can purchase their kelp from the U.S., from known monitored waters, by farmers in their community, rather than stuff that primarily comes over from China through [South] Korea—dried, dyed, and then shipped over,” he says.

As for Lindell, he sees enormous potential not just for sugar kelp, the species his lab is mapping. His team’s work could help regenerate other kelp species, too, including giant kelp in California and bull kelp in Alaska. And the kelp-farming industry could be the driver. More funding goes into farming kelp than preserving it in the wild, but the science applies equally: “All the learnings of the industry around resilience, growth, health, and disease resistance is going to carry over to conservation.”

This story was produced in partnership with the Pulitzer Center’s Ocean Reporting Network.

The post Rescuing Kelp Through Science appeared first on Civil Eats.

Now, she says, “it takes us a while to even get a couple of dozen clams. That’s not right.” She points out that most of the shellfish she harvests these days have been seeded manually by the town of Southampton and local universities, “almost like a science project,” she says. “The natural way has been contaminated and polluted by mankind.”

What’s also not right: the quality of the quahogs. “The shells are so brittle,” she says. The increasingly acidic water in the bay makes it hard for the clams to build strong shells. She points to her necklace of wampum—mollusk-shell beads that are integral to Eastern Woodland Native American culture. Hers is a single large indigo-and-white pendant, half an inch thick, the way shells used to be.

Genia, a member of the Shinnecock Nation, has lived along these waters on the South Fork of Long Island, New York, for most of her life. Shellfish are a traditional food source for the Shinnecock; they were also once the backbone of Long Island’s robust commercial fishing industry. Her tribe witnessed the crash of the clam and scallop fishery in the 1990s and then another crash in the 2000s, which further depleted shellfish stocks and threatened the nascent farmed oyster industry. Both were caused by massive blooms of harmful algae.

In 2020, after watching the decline of Shinnecock Bay—a body of water that has fed her tribe for some 13,000 years—Genia worked with Tela Troge, a tribal lawyer, to form the Shinnecock Kelp Farmers, a group of five Indigenous women who grow kelp to fight climate change. The group hopes to heal their afflicted bay and inspire a new generation to adopt more regenerative practices on the water. “We want our children to be able to go out there and clam and collect oysters and scallops and mussels like we used to,” says Genia. Plus, Shinnecock women are water protectors, she says, and being out on the bay is “in our DNA.”

The women’s move toward seaweed as a solution is emblematic of a shift across the country as the world’s oceans change faster than scientists ever expected. Since the 1990s, ocean acidification—caused by more carbon in the atmosphere dissolving into the sea, among other factors—has increased at alarming rates; in the U.S., the West Coast is especially impacted. Increased acidification means crustaceans in their critical larval stage cannot pull enough calcium carbonate from the water to create shells.

By 2015, acidification had become so significant globally that the United Nations addressed the crisis as part of its Sustainable Development Goal 14: Life Below Water. Their guidelines have spurred government investment, university research, and private interest to tackle acidification ever since.

Nitrogen-rich wastewater, another byproduct of rapid human development, feeds huge blooms of algae (known as “red tides” or “brown tides,” depending on the species) that starve other marine life of oxygen. Some algal blooms produce toxins that make shellfish unsafe to eat. The blooms are a particular problem in shallow waterways like Shinnecock Bay.

These twin phenomena of acidification and algal blooms are deadly for all crustaceans, including shellfish. And they can spell disaster for coastal communities, as 3 billion people globally rely on “blue foods” from the ocean, including shellfish, as a primary source of protein.

But recent scientific studies show that as the ocean becomes unfriendly for shellfish, seaweed could offer a solution—in particular, the large brown algae called kelp. Wild kelp forests form the most extensive marine-vegetated ecosystems in the world. They grow on every continent except Antarctica and provide habitat and food for the ocean’s smallest creatures to its largest.

Rich in minerals, kelp grows quickly and doesn’t require fertilizer. It isn’t seriously affected by acidification or algal blooms, and in some cases, it can even mitigate their impact on shellfish, because kelp soaks up excess nutrients like nitrogen and increases oxygenation in the waters around it. What’s more, the fibrous plant, which can grow two feet a day, also pulls anywhere from five to 20 times more carbon from the atmosphere than any terrestrial crop, something that leading marine scientists are working to quantify right now.

Because of these beneficial properties, kelp is being hailed as a miracle, a panacea for the climate crisis. Scientists, coastal governments, and private industry alike think it could be the cornerstone of a new, blue economy that allows coastal communities in the United States to transition from extractive industries into more sustainable ones.

Bolstered by roughly $380 million in investments since 2018, kelp farmers have proliferated from around zero in 2012 to 108 active farms in 2023, according to Connecticut Sea Grant, part of a national network of university-based programs dedicated to encourage stewardship of marine resources. Seaweed farming, a longstanding tradition in Asia for more than a hundred years, is now gaining a place on U.S. shores.

The Scientists Who Kickstarted American Kelp Farming

Charles Yarish holding Saccharina japonica seaweed offshore of Wando, South Korea, in 2023. (Photo courtesy of Charles Yarish)

Charles Yarish, now a visiting scientist at the Woods Hole Oceanographic Institute in Massachusetts, is considered the father of American seaweed farming. Gregarious and welcoming, Yarish can talk kelp nonstop. In 1976, as a new assistant professor at the University of Connecticut’s Department of Ecology and Evolutionary Biology and also its Department of Marine Sciences, Yarish became increasingly fascinated by kelp’s ability to pull nutrients from the water column. He suspected that farming kelp and other seaweeds could help alleviate water quality issues.

Toiling away at his Connecticut laboratory and conducting experiments in the Long Island Sound, Yarish spent the next few decades proving this hypothesis, focusing mostly on how kelp can pull nitrogen from waterways. “The farming of seaweeds such as kelp not only has business applications but is terribly important for ecosystem services, removing [excess] nutrients from ocean waters and lowering pH,” he explained.

Those early studies have impacted the growth of mariculture studies globally. At UConn, Yarish established an internationally known Seaweed Marine Biotechnology Laboratory, and was tapped to advise the Department of Energy’s current MARINER Program, which has invested $66 million in seaweed aquaculture since 2018.

Charles Yarish looks over recently collected kelp with a student in a lab at the Stamford campus in 2013. (Photo credit: Peter Morenus, University of Connecticut)

In 2016, scientists in Maine, alarmed by their state’s warming waters and increasing acidification, and inspired in part by Yarish’s early work, began studying whether kelp could provide a sanctuary for shellfish. Using the country’s first-ever commercial kelp farm in Casco Bay and funded by a constellation of government, nonprofit, and academic groups, the effort was led by Nichole Price and her team at the Bigelow Laboratory for Ocean Sciences.

After three years, they determined that co-growing blue mussels with sugar kelp—Saccharina latissima, the go-to variety of farmed seaweed for colder North American waters—led to increased oxygenation in the water. The scientists also documented kelp’s ability to locally raise seawater pH, which allowed the mussels to build thicker shells despite the acidic waters.

Price dubbed this the “halo effect” of kelp. She plans to continue monitoring outcomes to see how farms will fare in the future, since Maine’s waters are predicted to be too acidic for shellfish to calcify for most of the year by 2030.

Price said evidence is growing to support the idea that co-growing shellfish and seaweeds can offset the impact of climate change. The scientific field is tackling some big questions that could benefit the kelp farming industry. Including, she said, “Is it a consistent halo effect, or is it only in these protected bays? Or does it depend on the size of the kelp farm? If it’s a really big kelp farm, can it still create a halo even in exposed areas?”

While scientists race to understand the best growing methods for seaweeds with shellfish, the co-growing concept has been widely marketed by Bren Smith of GreenWave, who was first introduced to kelp by Yarish in 2013, after Smith’s oyster farms on Long Island Sound were decimated by hurricanes. Smith’s brand of co-growing focuses on a polyculture ocean farming model that combines shellfish with seaweed, an idea that he propagated in a book, Eat Like a Fish, and in GreenWave’s instruction manuals for “regenerative ocean farming,” which the group said thousands have used.

Although scientists on both coasts are still studying the effects of co-growing kelp with shellfish species like oysters—which fetch higher market value but generally grow in different environments than kelp—Smith promoted the idea of growing shellfish and oysters together, and is widely known in the industry for popularizing this approach.

Growing shellfish alongside seaweeds or finfish is a practice long used in Asia, especially China. However, it has been slower to catch on in the U.S., in part because of the lack of trials here. Inspired by the Asian approach and by Price’s work in Maine, in 2018 marine scientist Chris Gobler began focusing on kelp’s potential to heal his local waterways in New York, where algal blooms posed a bigger threat than acidification.

Eastern Long Island in particular was burdened with aging, failing septic systems that leached nitrogen into groundwater and ponds, lakes, rivers, streams, and bays. That excess nutrient runoff, combined with warmer waters, essentially fertilized the growth of harmful algal blooms yet again that year. Large swaths of open water were closed to shellfish harvesters by the New York State Department of Environmental Conservation.

Although Price was studying the co-raising of kelp with mussels to offset acidification, there was no scientific evidence yet to show how kelp could help shellfish during algal blooms. Gobler, working out of Long Island’s Stony Brook University laboratory, thought that kelp might benefit oysters. Aided by Michael Doall, a former commercial oyster grower–turned scientist who’d devised a way of growing kelp in shallow waters, Gobler launched a three-year study in 2019, hoping to find a solution for Long Island’s troubled waters that could be applied on both coasts.

By 2022, he had his answer: “We’ve learned the seaweeds can inhibit harmful algal bloom and even represent a direct food source for the bivalves as they slough off microbial cells.”

An illustration of the life cycle of sugar kelp, showing how it grows and develops over time. (illustration credit: Nhatt Nichols)

What’s more, Gobler’s lab had proved that raising kelp with oysters led to faster-growing, healthier shellfish. Gobler dubbed the phenomena the “halo effect”—a nod to Price’s studies—noting that the kelp around oyster cages provided a “halo” of increased oxygenation to the oysters as the kelp grew. At the same time, the kelp removed excess nitrogen from the water column. Backed by Gobler’s studies and studies from Price at Bigelow Labs in Maine, the idea of raising shellfish with kelp is now spreading across the country, including to the West Coast, where acidification is even more pronounced.

A Kelp-Farming Breakthrough

Michael Doall, a scientist at Gobler’s laboratory, solved the problem. A former oyster grower, he saw the business potential for a crop that not only had ecosystem benefits but could be harvested in winter, opposite the main harvesting time of summer for oysters—providing two income streams from the same patch of water.

To pave the way for a kelp-meets-oysters business model that would work on Long Island, Doall decided to try growing kelp in shallower waters. In December 2018, accompanied by oyster farmer Paul McCormack, Doall began an experiment on Long Island’s Great South Bay. The two men sank metal screw anchors into the sandy sea floor and strung long nylon lines, inoculated with kelp spores, between them. And then they waited.

Over the next few months, the kelp not only grew, but outperformed their predictions. Doall and McCormack were ecstatic. “It worked really freaking great,” recalled Doall. Gobler, using the findings, then put sugar kelp to work in his breakthrough kelp-and-oyster co-raising study.

Using Doall’s growing techniques and the science from Yarish and Gobler’s laboratories, at least 10 sites across New York are now using sugar kelp to pull excess nutrients out of the waterways. They are also collaborating on a recently proposed $700 million project at Governor’s Island that relies in part on seaweed farming to help prepare New York City for climate change.

Although seaweed grown as a bioremediation strategy cannot be used for human consumption—in some cases, as with RETI Center’s project in the Gowanus Canal, the kelp harvested showed high traces of polycyclic aromatic hydrocarbons (PAHs), a known carcinogen—scientists are experimenting with other potential uses for it, such as a kelp-based concrete.

Kelp Farming for a Tribe’s Future

“We are a frontline community and we have nowhere else to go,” said Danielle Hopson Begun, communications director and hatchery manager for Shinnecock Kelp Farmers. Hopson Begun is equally comfortable out on the bay or giving public talks, where she spreads the climate-saving mission of the group.

“When you’re hearing on the news about sea rise and acidification and you’re able to move yourself from Southampton Village to higher ground—good for you. It is not good for us,” Hopson Begun said. “For us, it [is] a moral imperative to preserve our way of life.”

To start their nonprofit, Shinnecock Kelp Farmers worked with GreenWave and Doall, who provided sorus tissue, the reproductive area of the kelp blade, for propagation. They found a home for their hatchery in a wooden cabin at the nearby St. Joseph’s Villa, a summer retreat for nuns. The wooded estate overlooks Shinnecock Bay, which now holds their kelp lines. For the 2023-2024 season, the farmers planted 30 lines at 100 feet each, a crisscross of golden-brown algae ribbons dancing beneath the water. As a sovereign nation, the Shinnecock did not need New York State’s permission to begin farming, and in 2020, they became the first seaweed growers in the state.

The group dries and processes their kelp by hand, turning the slippery curls of seaweed into hundreds of pounds of nitrogen-rich soil amendment that they use for gardening, sharing it with the local community at farmers’ markets. They lay the kelp out in donated screens, or along the pool fence at St. Joseph’s Villa, first washing the salt off the seaweed and then waiting for the sun to bake the kelp down.

Eventually, the heat crumbles the kelp into a dry, brown powder that plants love. Through this process, the nitrogen sequestered from the water column returns to the soil, a closed-loop nitrogen cycle now in vogue with organic farmers—although Shinnecock have been growing crops using seaweed as fertilizer for thousands of years, said Hopson Begun. Seeing the decline of seaweed in the bay in recent years, and knowing its benefits to shellfish, prompted them to start farming seaweed themselves.

While satisfying, the work is demanding, sometimes requiring the women to get up and work in frigid waters at dawn. For a recent November planting, they waded into 38-degree water during the first snow of the season, unspooling their kelp string as a hushed snow fell. But Hopson Begun wouldn’t trade it for anything. She said, “I love seeing something so small grow into something really incredibly powerful that potentially can make a big difference.”

Is Kelp the Answer for West Coast Shellfish?

In 2007, this reached a crisis: Oyster businesses were devastated up and down the West Coast because baby bivalves simply could not grow.

“When it came time for our [oyster seed] orders to come in, the hatchery said, ‘We had a complete crash. If anything survived, we are going to be supplying our own farms, not you,’” recalled Terry Sawyer, co-founder of Hog Island Oyster Co., a Northern California favorite for its shellfish-focused restaurants. “We were sitting there, flapping in the wind.”

Trained in marine biology, Sawyer is an entrepreneur and lifelong ocean lover. When he and his co-founder, John Finger, realized how catastrophic the situation was, it spurred them to embrace a whole new outlook on marine conservation. Hog Island now regularly hosts marine scientists to study the effects of warming waters on nearby marine life. The company also collaborates with the Central & Northern California Ocean Observing System, providing real-time data from their farm on ocean acidification as part of a global effort to understand why the ocean is changing so fast.

Acidification led Hog Island, based on Tomales Bay, just north of San Francisco, to establish their own hatchery further north in Humboldt Bay, so they could ensure their whole line of production, from larvae to finished oyster. The process took about three years, and cost $125,000 in permitting fees alone, paid to the California Coastal Commission. Sawyer said the decision was the only way they’ve survived a situation that is cyclical for West Coast waters. Hog Island buffers the water at their hatchery by adding soda ash to make intake seawater less acidic, allowing the larvae to grow. The technique is now common practice; West Coast farmed bivalves cannot grow in the open ocean anymore.

“I love to say, ‘If we have a problem, we have to figure out how to eat it,’” said Sawyer, pointing out that seaweeds are a “winner” crop if ocean acidification continues to rise. “We are going to need to look at organisms that aren’t as impacted by pH change.” For now, though, Sawyer has to wait to unfurl kelp lines in Humboldt Bay, as the California Coastal Commission has no regulatory process for inshore commercial seaweed operations.

Instead, Hog Island has been collaborating with GreenWave and The Nature Conservancy on a non-commercial research pilot study since 2021, growing bull kelp at the Hog Island hatchery in Humboldt Bay. The waters are notably less acidic near the kelp lines—a promising result as the Hog Island team waits for California’s permitting structure to change for a commercial kelp farm.

The Promise of Seagrass

However, wild West Coast seagrass meadows and kelp forests are declining, and that makes Hill very worried. Subjected to stress from marine heat, acidification, pollution, predation by sea urchins, and human encroachment, these water-based ecosystems may lose their power to help fight ocean warming. “The more we protect habitats like seagrass meadows and salt marshes, the better chance we have at climate mitigation,” said Hill. She sees promise in seaweed farming for the same reasons.

Helpful marine organisms—like sugar kelp, bull kelp, and seagrass—could help reduce some of the worst climate impacts that scientists are documenting on the U.S. coasts. Raised in quantity, they could bring at least some stretches of shoreline back into balance, allowing marine life to thrive again in our waters.

The Shinnecock Kelp Farmers are starting to see it happen, bit by bit. “The most darling was a little tiny scallop that took up space on one of our lines. They’re endangered,” said Danielle Hopson Begun. “To see that little guy holding to and finding a place in our farm was very satisfying.”

This series was produced in partnership with the Pulitzer Center’s Ocean Reporting Network.

The post Can Seaweed Save American Shellfish? appeared first on Civil Eats.

Today, consumers can find burgers, chips, and even a cannabis gummy made from domestic farmed seaweed, and a recent Nielsen report estimated the value of the edible seaweed industry  to be $1.87 billion in the U.S. One particular type of seaweed, kelp, has come to the fore: More than 2 million pounds were pulled from coastal U.S. waters during the 2022-2023 season, and experts predict that the 2023–2024 season will be even larger.

What’s driving this growth? The answer goes beyond seaweed’s industrial applications or the fact that Americans are developing a taste for kelp as a nutritious, low-calorie food. Scientists say this seaweed also offers a multitude of ecosystem benefits. Kelp can pull excess carbon out of the atmosphere—with some estimating that it sequesters at least 10 times more carbon than a terrestrial crop. It reduces ocean acidification, too, and removes the excess nitrogen that feeds massive algal blooms, a threat to other marine life.

This scientific proof of kelp as a regenerative crop that could save our seas has helped the industry attract rapid investment—according to our estimates, roughly $380 million since 2017, from sources including the federal government, corporations, venture capital funds, coastal state spending, and nonprofits. Kelp could also help climate efforts on land, in industries ranging from textiles to plastics to beef.

As Silicon Valley and others turn their sights to this remarkable seaweed, the time is ripe to ask critical questions about the future of an industry that could be rapidly expanding. Will smallholder farmers, whose work has been pivotal in setting up domestic seaweed production, reap the benefits of the industry’s growth? Or will multinationals move in, growing seaweed at scale—potentially boosting ecosystem benefits, but perhaps also introducing the environmental repercussions of monocropping? And will federal money flow to small farms as well as large?

Regulations are at issue as well. Small coastal growers now navigate a tangle of legislation, with no one entity claiming oversight. The country’s first seaweed bills now sit in Congress, with the potential to unleash a new round of investment in an industry that is still not tracked by the U.S. Department of Agriculture or the National Oceanic and Atmospheric Administration. Could large investors leapfrog to offshore farms, where the regulatory environment may be more permissible?

In this series, we’ll ask those questions and more. For context, we’ll trace the rise of seaweed farming in the U.S. and profile small farmers who are using kelp to both mitigate climate change and adapt to its impact. We’ll explore how scientists are creating more efficient ways of growing kelp while also protecting the future of wild kelp forests.

Tightening our focus, we’ll look at the main issue vexing kelp producers today—laborious processing—and a company that’s trying to solve that problem. Our final story will go macro, with a view of the venture-funded pilots that may shape a future of seaweed driven by corporate investment.

The stories in this series provide a framework for how we might guide the future of kelp, and how it may—or may not—fulfill its potential as a climate solution.

This series was produced in partnership with the Pulitzer Center’s Ocean Reporting Network.

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