An illustration of sea animals cut out of a red tide
Eric Nyquist

Deadly Algae Are Creeping Northward

In a warming ocean, Alexandrium algae are shredding marine food webs—and disrupting beloved Alaska traditions.

Updated at 12:58 p.m. ET on November 1, 2019.

In the late winter of 2015, more than 1 million common murres—prim, black-and-white seabirds—died off the shores of Alaska. They’d been washing up all along the Pacific Coast that winter, as far south as California. But in Alaska, the die-off took over our lives, dominating the front pages of our newspapers, our back-and-forths on social media, our conversations at school pickup.

Where I live, in Homer, about 200 miles south of Anchorage, the dead birds checkerboarded the beaches so completely you could walk the wrack line on their backs. Bald eagles dismantled the carcasses in backyards and parking lots. I edged along the shoreline in wonder and horror. My daughters, 3 and 6 at the time, picked up the still-whole bodies and cradled them like dolls.

Murres are tenacious hunters, diving up to 600 feet underwater to catch fish. But these birds had starved to death, researchers concluded, likely because the so-called Warm Blob, a pool of water in the North Pacific that was strikingly warmer than normal, had made it impossible for them to find enough food. No one could say why.

I couldn’t drop it. I wanted to know exactly what was happening to the birds. In the years since, there have been other inexplicable die-offs of sea life—thousands of puffins wrecked on the Pribilof Islands, 100 million Pacific cod vanished from the Gulf of Alaska, dozens of walrus washed ashore on the state’s northwest coast, and more than 200 gray whales marooned on beaches between Mexico and Alaska. If we didn’t know what caused these phenomena, I thought, weren’t we doomed to just sit back and watch as they happened again and again and again?

So I ended up traveling to the remote Popof Island, in far western Alaska, with a scientist named Bruce Wright. Wright feels certain that he knows why the murres died. He blames a type of microscopic algae that floats in every ocean on Earth.

The skies around Anchorage were smoky when Wright and I took off aboard a 45-seat propeller plane. Alaska is warming at twice the global average, but spring and summer this year were particularly sweltering—by northern standards at least. Temperatures around the state shot up to 41 degrees higher than normal, and the heat stoked wildfires across the state. Ocean and river temperatures soared too. As my daughters and I basked in the surprisingly balmy waters in our bay, salmon floated dead on the surface of the Kuskokwim River up north, likely victims of heart attacks brought on by the heat.

The warm water also created perfect conditions for toxic algae to bloom. By early June, clams in Southeast Alaska contained 55 times the safe limit of algal poisons.

The problem of toxic algae or “red tides”—which scientists refer to collectively as harmful algal blooms, or HABs—occurs when algae that produce natural poisons grow explosively, impacting human or ecosystem health. Many different species of algae cause HABs, and they can last for weeks or longer, decimating fisheries, closing swimming beaches, and making it hard for coastal residents to breathe. In the sea and in lakes, they have killed fish, birds, turtles, whales, manatees, and even dogs. During the summer of 2018, after HABs left millions of pounds of dead fish and other sea life piled up in Florida’s coastal towns, Governor Rick Scott declared a state of emergency.

Globally, HABs are exploding. In recent years, toxic blooms have started to occur in places where they’ve never happened before, and during more months of the year. The expansion of HABs is linked to rising sea temperatures, but pollution, the dumping of ballast water from ships, and the transplantation of shellfish stocks may also play a role.

The most notorious impact of HABs is paralytic shellfish poisoning, or PSP, a disease that can kill a healthy adult with just one tainted mussel. It’s the algae that cause PSP—called Alexandrium—that preoccupy Wright. Fifty years ago, few places in the world were affected by Alexandrium. Today, a global map of PSP outbreaks looks like a case of measles.

The smoke dissipated as we flew southwest over the snow-tipped peaks of the Alaska Range, where mountain valleys held the blue ice of shrinking glaciers. The flight path took us down to the tip of the Alaska Peninsula, the 500-mile-long curve of land that separates the Bering Sea from the Gulf of Alaska. Beyond, the Aleutian island chain arced another 1,200 miles across the international date line.

Popof Island, a hunk of tundra-draped rock that stretches 10 miles tip to tip, sits at one of the most biologically rich marine crossroads on Earth. Swift currents deliver food and nutrients into submerged canyons that act as nurseries for hundreds of fish species. These rich waters also support more than two dozen kinds of marine mammals, with narrow ocean passes serving as crucial corridors for nearly all of the planet’s gray whales. Millions of salmon pass through these waters as well, on their way to the world’s largest sockeye fishery, and as the currents spill into the Bering Sea on their way to the Arctic, they fuel crab and pollock harvests worth billions.

For longer than anyone can remember, people have come to this region for the bounty of the sea. The Unangan people lived in partially underground houses called barabaras, developed a written language, and paddled sleek skin boats through the water to hunt and fish. Then the Russians and Scandinavians, and later American corporate interests, arrived to profit off the sea. Wright and I were headed to Sand Point, a village of about 1,000 people and Popof’s only settlement. Home to the largest commercial fishing fleet in the region, it is a place where a modern, extractive economy has fetched up alongside ancient traditions. As we approached the community, I could make out the tan warehouses hunkered near the harbor of the Trident Seafoods plant, which can process up to 30,000 pounds of fish an hour.

Within two generations in the village, PSP has gone from a problem no one had to think about to a summertime concern to a year-round plague. Wright hoped that with data from the edge of this far-flung island, he could help explain how this microscopic organism is poisoning our seas.

Life on Earth evolved in shallow seas, at a time when the sun shone dimly. Simple cells, messy sacs of planetary soup, figured out how to turn this glimmer into food, opening an evolutionary path for photosynthetic algae. Alexandrium are a relatively young genus of these algae, showing up about 77 million years ago, when Earth’s dinosaur party was well under way.

Since the 1960s, when a French scientist discovered a bloom in Egypt’s Port of Alexandria and named the genus accordingly, we’ve learned that Alexandrium algae can thrive all over the globe with ratlike adaptability. They can make their own food through photosynthesis, or gorge on other microorganisms. They can reproduce alone or with a mate. They can live as single-cell loners or form chains of cells that swim together like a snake. Some even glow. And when the water gets too chilly in winter, they can go into a dormant form—known as a “cyst”—and sink to the seafloor until conditions improve.

Members of the Alexandrium genus produce one of the most powerful neurotoxins on Earth, a chemical called saxitoxin that is so noxious a single sand-sized grain can kill eight people. The poison blocks sodium-ion channels in the brain, quickly paralyzing the respiratory system of its victim. The U.S. military developed the toxin as a chemical weapon, and during the early years of the Cold War, the CIA issued a saxitoxin-laced needle—hidden inside a fake silver dollar—to a U-2 pilot carrying out spy missions across the Soviet Union, in case he was taken prisoner and needed to induce suicide.

The word saxitoxin comes from the scientific name for butter clams, those beefy shellfish that have long sustained coastal peoples in my part of the world. And indeed, Alaska has a long, uneasy history with PSP. The earliest—and deadliest—recorded outbreak was in 1799, when Russians were pillaging the region for furs. That year, some 100 Alutiiq men working as hunters for Russian businessmen died from eating toxic mussels. The nautical charts of Southeast Alaska carry the scars of that PSP outbreak: Poison Cove, Peril Strait, Deadman Reach. Nine years ago, Alaska health officials reported two deaths from PSP, but numerous milder cases—where people suffer from some combination of tingling and numbness around the mouth, vomiting, diarrhea, and double vision—crop up every year.

In decades past, PSP incidents were almost entirely confined to Alaska’s most southerly shores. When I first moved here 20 years ago, I harvested clams and mussels from local beaches with abandon. When my daughters were little, we used to plan camping trips around minus tides, when acres of clam and mussel beds were exposed in our bay. We’d take some hand rakes and a few buckets and tromp around in rubber boots and bibs, digging steamers and collecting slick, black clumps of mussels. Then we’d steam up our haul right on the beach and all eat out of one pot. Eating straight from the sea like that always felt like some kind of communion.

Like moose and mackerel, songbirds and spruce, toxic algae seem to be moving poleward because of climate change. In Alaska, this means that PSP is slinking north up the state’s 34,000-mile coastline. Recent research has found PSP toxins just about everywhere in our northern waters. A study of Alaska’s marine mammals that tested 13 different species for algal toxins found the poisons at sublethal levels in every one—including bowhead whales, which spend their lives near Arctic sea ice. And a few years ago, scientists found Alexandrium cysts in Arctic waters in some of the highest concentrations on the planet.

Just outside the one-room Popof Island airport, we rented a white Chevy pickup from the woman who owns the Harbor Café. All along the newly paved road to town, golf-ball-size salmonberries dangled from dense bushes, glinting scarlet in the sun.

Before checking into rooms at the only hotel in town, Wright and I stopped by the headquarters of the Qagan Tayagungin tribe. Wright, dressed in khaki from head to toe, sat down opposite the tribal director Tiffany Jackson, a young mother of three. Her long, black hair hung down her back from a beaded barrette. Jackson’s staff sends weekly shellfish samples to Wright in Anchorage, and he’s found that they contain some of the highest toxin levels of any of his sites.

“With people not being able to get clams,” Jackson told Wright, “they’ve been relying on bidarkis.” Bidarkis are mollusks with a single plated shell that clamps tightly onto rocks. You can boil them whole and pull away the shell to get at the chewy meat. “Have bidarkis gotten a hit?,” she asked. “Yup,” he replied. Different types of shellfish process algal toxins in different ways, but now even the island’s Plan B food contained the poison, although at lower levels. “I just fed them to my family two weeks ago,” Jackson said. “We’re still alive!” she laughed.

Locally harvested foods are an important part of the culture here—and not just because a gallon of milk, flown or barged in from Anchorage or Seattle, costs $10 at the Alaska Commercial grocery.

“Subsistence is part of who we are,” Jackson told me when I stopped by her office later. Eating food from the land and the sea—the gristly humps of pink salmon, seagull eggs, urchin roe, clams—is an expression of cultural identity. It’s also how Jackson likes to spend time with family. Her father taught her how to eat bidarkis right on the beach when she was a kid. And after she and her children pick moss berries or gather bidarkis, they head to her mother’s house to prepare the harvest.

An illustration of a murre eating sand lance
Eric Nyquist

Jackson’s husband, Charlie, a commercial fisherman, is known in the village as the guy who distributes salmon to local elders. “They don’t have a way to fish,” he explained. Though it was only midsummer, he’d already put up 1,000 fish, he told me when he showed me around his shop where scores of twinned salmon filets split to the tail hung from wooden racks. Soon he’d pass the dry fish around to elders. “They love it,” he said.

Jackson grew up in Sand Point following the ‘R’ rule—digging clams and gathering mussels only during the months with an r in their name. Collecting clams was a winter ritual for her family: She remembers how they would park their truck in the dark at the edge of the beach, scuffle over ice and snow, and dig in the beams of the vehicle’s headlights. “Five years ago, I would never have believed that we couldn’t dig clams,” she said. Now, there’s no safe time of year. Some locals get clams through the school fundraiser, which raffles off bucketsful from King Cove, an 80-mile boat or plane ride away. There, by a fluke of oceanographic luck, the PSP levels haven’t been as high.

The morning after we flew in, Wright and I headed out of town on the paved road to the dump. We pulled off where a four-wheeler track tore across the tundra in a dirt stripe gilded by buttercups. The trail followed the edge of the headland down to a cove called Sand Dollar Beach, where Wright planned to collect samples of marine life for testing.

From the cliff’s edge we could see half a dozen salmon seiners, and beyond those the rocky cliffs of the Alaska mainland. Golden-crowned sparrows sang their melancholy three-note call, and kittiwakes and gulls whined over a bait ball not far offshore.

Wright got started in the field of toxic algae in the early 1980s, when he was sitting around with a bunch of guys at a friend’s house watching a football game and gorging on steamer clams they’d just collected from a nearby beach in Juneau. The friend’s cat got hold of one of the clams—and then wandered into the garage and died.

Human health drove most of the early research on Alexandrium. But Wright’s background is in top predators, including raptors and sharks, and he came to the field with an interest in the algae’s broader ecological effects. In the years since, he’s recorded the highest PSP levels in the state’s history—from blue mussels in a picturesque cove in Southeast Alaska that measured 270 times the safe limit—and has worked with coastal villages around the state to set up regular PSP monitoring.

The retreating tide had exposed a wide stretch of sand. In tall rubber boots, a black waterproof pack on his back, Wright walked across the beach with his head down, scanning the ground for clues. I stepped across the beach in a sort of reverse hopscotch, careful not to tread on the chocolate-brown, saucer-size sand dollars nestled in the sand.

At the far end of the beach, a rocky reef had emerged with the ebbing tide. It gave off that salty low-tide musk that I love. The traditional saying goes: “When the tide is out, the table is set.” Packed with high-protein, slow-moving creatures, the intertidal has always provided year-round, accessible sustenance.

Wright and I clambered across the reef with shared glee. “Check out these bidarkis,” he called. “Cool!” he shouted when I held up a coral-colored crab covered in hairs. Wright grew up landlocked in the Mojave Desert, where his father worked at the nearby naval base. In the summer, the family escaped for a couple of weeks to the California coast. “I just never got tired of being in the tidepools,” Wright said. “Now it’s my job.”

As I wandered over to a vermilion-colored blood star, Wright popped a dozen or so bidarkis off the rocks, using a knife he kept on his belt, and dropped them into a ziplock bag. He bagged a few limpets, mollusks with cone-shaped shells, then mussels, gunnel fish, shrimp, amphipods, sand dollars, and a fist-size, snail-like hairy triton. He sliced a single leg off a sunflower star and bagged it too.

Then Wright set across the beach in search of sand lance, finger-size, silver fish packed with protein and fat that are a favorite meal of murres, and of dozens of other marine animals, from halibut to humpbacks. Sand lance feed on copepods—minute, floating crustaceans—which feed on phytoplankton, including Alexandrium, sending algal toxins up the food chain.

Wright stopped every few paces, split his legs into a wide stance, folded his 6-foot-2-inch frame, and scraped a garden rake through the sand, rapidly turning over an area of the beach the size of a card table. Soon, the cove was a patchwork of hash marks, but again and again, he found nothing. Wright hoped to catch sand lance—and the other marine organisms—in the midst of an Alexandrium bloom. If he could get a measure of peak toxicity in the food web, he might be able to understand just how destructive this algae could be.

Finally, a flash of silver. And then another. And another.

“These are the guys we really want,” Wright grinned as he dropped the fish into plastic bags.

The impact of Alexandrium on marine ecosystems is likely a one-two-three punch. We know for certain that these algae can kill ocean fauna outright. When captive mallards are fed concentrations of saxitoxin that they could readily encounter in the wild, they die as quickly as 15 minutes after dosing. There aren’t many records of wildlife deaths from poisoning, but some researchers believe that’s because whales, salmon, and other marine animals killed by PSP simply sink to the bottom of the sea and disappear.

Alexandrium could also be an indirect killer, poisoning prey species like sand lance so that predators suffer or ultimately starve. This is what Wright believes happened to the murres. PSP wiped out so many sand lance and other prey fish, he thinks, that the birds had nothing to eat.

In addition, the algal toxins could weaken and slow marine organisms. While the kinds of low levels of saxitoxin that researchers have found in seemingly healthy walrus, whales, and seabirds aren’t killing them outright, the poison might make it harder for a murre to catch fish, a walrus to vacuum clams from the seafloor, or a bowhead to breed.

“Up until recently, I’ve been the only voice that says that saxitoxin is taking out the bottom of the food web,” Wright told me. Scientists are famously circumspect when it comes to identifying causal relationships. But Wright hasn’t been, and for years he has operated as a lone ranger, pursuing PSP research on shoestring budgets outside of any mainstream governmental or academic institutions. “I’m the only one willing to make predictions,” he said.

Now, at age 67, Wright is beginning to see a shift. “Finally, people are getting on board,” he said. Today, he maintains an email list of 1,400 people interested in his work, and he’s one of more than three dozen scientists who are collaborating on a multimillion-dollar proposal to study the effects of toxic algae on Alaska’s marine food webs. Now, when whales, walrus, and seabirds wash ashore in unusual numbers, their carcasses are routinely tested for algal toxins.

Still, no one seems as quick as Wright to point the finger at PSP. “It’s really one factor out of the bazillion that’s affecting these organisms,” Kathi Lefebvre told me. She’s a National Oceanic and Atmospheric Administration scientist who is heading up the huge, multiagency proposal. “It doesn’t mean it’s the only cause.”

John Piatt, one of Alaska’s leading seabird biologists, describes himself as an “extreme skeptic” about the role of PSP in the murre wreck and other marine die-offs. He and other scientists blame the impacts of warmer temperatures on animal metabolism: With warmer sea conditions, he explained, murres, sand lance, and other ocean organisms need to eat more, so every link in the food chain goes hungry, and every prey species is less nutritious to the predator above it. During the murre die-off, there simply weren’t enough protein- and fat-laden fish to keep the birds alive.

But Piatt has witnessed the effects of algal toxins. During a study of Kittlitz’s murrelets—black and white seabirds dainty enough to fit in your palm—he saw chicks killed by eating PSP-laden fish. “I’m coming around here,” he admits.

Wright is undeterred by the skeptics. “It’s feeling less and less anecdotal,” he told me. “PSP really explains a lot of this stuff.”

I spent four more days on the island, and at times, hanging out with Wright was a bit of a buzzkill. One morning, looking down from a wooden footbridge over a slough near the harbor, we watched dozens of Dungeness crab scuttling through eelgrass. As the sunlight illuminated the water and picked up the crabs’ every move, all I could think about was a meal fresh from the sea, tasting that sweet white flesh from those luscious claws.

“I’d like to test those suckers,” Wright muttered.

And each morning, when I emerged from my hotel room into the sour, fishy smell that wafted up from the Trident plant, Wright announced with grim triumph some new development in the world of toxic algae. A die-off of sand lance had just been discovered on Kodiak Island, about 300 miles northeast, that he felt certain was to blame on PSP. Florida and Mississippi had just closed beaches due to HABs. And a New York Times reporter was eager to talk to him about his work.

Even without Wright’s news ticker, it would have been impossible to escape the mark of PSP on the region. At the Chinese restaurant where Wright and I had dinner, a young commercial fisherman said that her 83-pound dog Sadie had died from PSP a few years back—the same year her boyfriend died when the 98-foot crabber he was crewing on flipped and sank in the Bering Sea.

Another evening, I met the school librarian at one of the two bars in town. The last time she ate local clams, she told me, her son was a baby. “Now he’s 6,” she sighed.

When I wandered through the village cemetery one afternoon, where the triple-barred crosses of the Russian Orthodox church had been fashioned out of two-by-fours painted white, it seemed as though nearly half the dead were Gundersons, a reminder of the last person around here killed by PSP—Buddy Gunderson Jr., who died about 25 years ago after eating shellfish while out on his fishing boat.

I walked down to the Trident dock one afternoon where Taylor Lundgren’s 58’ F/V Temptation was tied up.* Painted a perky blue, it was a gorgeous, beamy boat that can hold about 200,000 pounds of fish. Lundgren fishes for salmon, cod, halibut, and pollock, but the fresh crab fishery has been eliminated by PSP.

I met Mark Patterson, a blond, suntanned pilot with the Alaska Department of Fish and Game whose personal ride is the Purple Princess, an eggplant-hued Cessna 180 parked at the edge of the airstrip. He used to eat clams, he said, until one night after a few glasses of wine and a meal of butters—he’d cleaned the guts and snipped the lips, the most toxin-laden parts—he could hardly walk home. He never went to the doctor, but he was pretty sure it was PSP.

When I got a tour of the Trident slime line, packed with Filipinos and tall Serbian men who, on shift breaks, ranged around in sweats and trainers looking like they had just stepped off a soccer pitch, the production manager Isaac Del Rio told me that a key part of orientation for new workers is the warning not to eat local shellfish.

And a few days after a local drunk asked me to fly off to Vegas with him to get hitched, I heard a rumor that he was the only one around who still harvested clams from nearby beaches. I wondered how much longer he’d be sipping Coronas at the bar.

Six weeks after Wright and I left Sand Point, he got the results back on his samples. “I missed the PSP event!” he told me. He was disappointed. Blooms are happening earlier in the year because of warming temperatures. A month before we’d arrived, the mussels had more than 200 times the safe level of toxins in their tissues. Since then, although they were still unsafe to eat, poison levels had dropped drastically. Even so, two-thirds of the creatures he’d brought back showed detectable levels of PSP.

Clearly, saxitoxin is everywhere, but is it killing our seas? Wright thinks so, even though he admits that his hypothesis is impossible to test. “There’s no way to solve it one way or another,” he said. “It seems that when you answer one question, 10 additional questions pop up.”

The mystery of the starving murres will probably never be fully solved. We can’t turn back the clocks to test whether PSP ravaged their food source, and even if we could, it would take a near-endless budget to sample the ocean waters these birds feed in to know for sure. But while we were on Popof, Wright predicted that another murre die-off would begin in a matter of months because of warmer-than-normal ocean temperatures. As signs flood in that the Warm Blob, which dissipated in 2016, is returning, I fear that he's right.

And what about those massive beds of dormant Alexandrium cysts in the Arctic? Will rising ocean temperatures and disappearing sea ice set off those ticking time bombs of toxicity? We can only wait and watch.

Tiffany Jackson and her family may never be able to dig clams on Popof again. This is one of the tragedies of climate change: At the very moment we need to feel connected to the natural world so that we’ll actually do something to protect it, in come forces—wildfires, disease-carrying insects, PSP—that rend us from it. During minus tides at home, when the clams and mussels are there for the taking, I feel this distance acutely.

The day of our departure from Sand Point, fog sat low over the island. To kill time as we waited for the ceiling to lift, I stashed my bags and hiked along the road back to town. I waded off the pavement until I was neck-deep in salmonberry bushes, and I feasted. Then I carefully laid a few layers of the delicate, juicy orbs into a small lidded container I had in my carry-on. When ripe, these berries can range in color from the peachy gold of a fresh king-salmon filet to blood red. They fairly glowed in the box. When I landed in Homer, I handed the berries to my daughters as soon as I stepped into our tiny, hometown airport. They huddled around the fruit as if nothing else in the world existed. And for a moment, nothing did.

*  We originally misidentified Taylor Lundgren as Taylor Larsen. (Larsen is his wife’s last name.)