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Wednesday, December 6, 2023

A Unique Alliance Could Help Warn Us of Toxic Algae

In 1991, Frank Cox, a biotoxin coordinator for the Washington State Department of Health, went digging for razor clams. He packed up his haul and sent the shellfish to a state lab to check for paralytic shellfish poisoning, the only marine toxin known to appear on that part of the coast.

The lab ground up the shellfish and mixed the tissue with solvents. Then, they injected the slurry into mice, a common testing technique at the time. But the mice started to do something peculiar. Instead of gasping for breath or dying—standard symptoms of paralytic shellfish poisoning—the mice started scratching behind their ears. The symptom, though seemingly innocuous, revealed a disturbing new toxic threat: Domoic acid had arrived on the West Coast.

Domoic acid is a deadly, naturally occurring neurotoxin produced by Pseudo-nitzschia, a genus of planktonic diatom or single-celled algae. When that algae is eaten by other marine animals, like mussels, clams, and Dungeness crabs, the acid concentrates in their digestive tracts and internal organs. And when those tasty marine treats are ingested by humans, the domoic acid can make people sick, causing headaches, stomach cramps, nausea, and diarrhea. In more severe cases, patients might also experience seizures, coma, and even short-term memory loss, which is why the illness is also sometimes referred to as amnesic shellfish poisoning. After the world’s first occurrence of domoic acid poisoning in 1987, three people died.

So when state officials found out what was happening in those mice in the lab in Washington, they quickly closed the entire state’s coastline. Electronic signs on the highway warned visitors away from clamming, and the Washington Department of Fish and Wildlife sent armed officers to patrol the beaches. “The public didn’t know what the heck was going on,” says Vera Trainer, an oceanographer at the National Oceanic and Atmospheric Administration (NOAA) who studies harmful algal blooms in the Pacific Northwest. 

She says at the time, there was a huge amount of suspicion and anger from members of the coastal communities, which include many indigenous tribes that rely on the shellfish harvest for food and income. “People said, ‘Oh, the government’s just saying this because they don’t want us to have fun. They don’t want us to collect what’s due to us,’” says Trainer.

Since then, toxic algal blooms that create domoic acid have continued to force the closure of state beaches. A few times, once in 1998-1999 and again in 2002-2003, the beaches remained closed for the entire clamming season. Now, in a paper out this month in Frontiers in Climate, Trainer and her colleagues find that climate change could also be affecting the frequency and severity of these blooms; they write that a heat wave that lasted from 2013 to 2015 has made the blooms even more common. But the paper also describes a solution: a unique partnership in which scientists and coastal community members can contribute to monitoring and managing these now perennial toxic blooms.

“It’s maybe not the perfect, wonderful answer that everyone wants,” says Trainer. She acknowledges that scientists haven’t figured out a way to end the blooms—and that they may never go away. But she says other types of progress have been made. “We are just getting much better at learning to live with these,” she says. “Yes, we’re finding them in more places. They’re more intense. We need to control climate change. But in the meantime, we can work with people on the coast to develop these systems that are going to help us still gain access to safe shellfish.”

Pseudo-nitzschia are found in oceans all over the world, but the area around the West Coast— from Northern California up to Washington—is particularly suited to creating blooms. The topography of the ocean floor and the coastline create retentive zones, areas where the water eddies and swirls, bringing all kinds of phytoplankton and algae, including Pseudo-nitzschia, up to the surface where there are plenty of nutrients and sunlight to help them grow. Trainer describes these as “little mini ocean Crock-pots.”

Thanks to that multiyear heat wave that started in 2013, many of these “Crock-pots” were seeded up and down the coast. Warmer water provides the perfect environment for the algae to thrive, and because those eddies also keep the algae and its toxic byproducts from being washed away and diluted by the rest of the ocean, those Crock-pots can grow into much larger, harmful blooms.

Global warming is likely making the situation worse. As climate change raises the temperature of the oceans, toxic algae has been moving into new areas farther north. And as a hotter planet makes the El Niño climate pattern, with its warm surface waters, more common, scientists expect to see more frequent toxic blooms too. Ryan McCabe, an oceanographer at the University of Washington, says it’s too soon to say for certain whether these “Crock-pots” are making blooms more frequent or more toxic, but he says that as the oceans continue to warm, he expects it to happen more often. That’s certainly what seems to be happening along the Washington coast, he says, where “we’ve had our fair share of extremely toxic events during the last five years.”

That has particularly affected local tribal communities, including the Quinault Indian Nation, the Quileute Nation, and the Makah Tribe, who rely on fishing and shellfish harvests. The state’s razor clam fishery alone can generate $1 million in revenue for these tribes, and the tourism associated with clamming can earn another $28 million. Many tribal members also dig clams for subsistence use and see it as an integral part of their heritage and culture. Representatives from both groups did not return requests for comment, but the Quileute Nation’s website notes that tribal members can’t just harvest clams and crabs anywhere. They only have treaties to do so on specific lands. “Unlike non-treaty fishers who can fish the entire Pacific coastline, the treaty tribes are place-based—they can only treaty-fish within their designated areas,” it states.

Scientists at NOAA, the University of Washington and state agencies like the Department of Health and the Department of Fish and Wildlife have needed to know more about toxin levels in the water, and the coastal communities have needed to have access to safe seafood. So, in 1999, they started working together, creating the Olympic Region Harmful Algal Blooms Partnership, through which the scientists train tribal members to take water samples and analyze them for toxins. These assays immediately determine how high toxin levels are, instead of having to wait three or four days for samples to be shipped to a lab in Seattle. This lets fishers know whether it’s safe to harvest seafood, while helping state officials keep an eye on toxin levels, avoiding emergency beach closures and warning people when they start to become unsafe.

Today the program, which originally started under a federal grant from NOAA, is funded by a small state tax on fishing licenses. Each participating tribe and Indian nation has its own technician, usually a member of the tribe, who takes samples weekly or every other week. With a Niskin bottle, which can take water samples from specific depths, and with phytoplankton nets, the technicians scoop up thousands of these single-celled algae from the beaches and water near the shore, bringing the samples back to labs set up nearby. Then the technicians examine their haul using a microscope. “The difficult part is identifying the phytoplankton and identifying the dangerous ones,” says Anthony Oddell, a research analyst at the University of Washington who trains technicians to take and analyze the samples.

There are thousands of types of phytoplankton along the Washington coast, and most are harmless to humans. But there are two culprits the technicians are on the lookout for: Pseudo-nitzschia, of course, and members of the genus Alexandrium, which produces the toxin that causes paralytic shellfish poisoning. (The partnership doesn’t have the tools to run its own analysis for other toxins, so the technicians also send samples to the Washington State Department of Health for testing.)

Just seeing the algae doesn’t provide enough data to know whether a toxic event is underway. Sometimes those dangerous diatoms are present but aren’t producing any toxins that could affect seafood. So if the technicians see a large enough number of toxic diatoms, they run an analysis called an enzyme-linked immunosorbent assay (Elisa) that detects how much toxin is present. They report those numbers to researchers at the University of Washington. That data gets combined with sampling information from researchers at NOAA and the university, who collect algae farther out in the ocean, and also with other data about the weather, ocean currents, winds, and satellite imaging—sometimes the blooms can be seen from outer space—to calculate what the risk of a toxic event might be. This information goes into a weekly bulletin showing what the toxin levels are in specific areas, using a color coding system that is easy for fisheries managers to read.

“It's a really hard problem, because conditions are constantly changing,” says McCabe, who helped create the bulletin. “The species that do produce the toxins don’t always produce the toxins. There’s a lot of uncertainty in making these, so as we continue to do the bulletins and make the predictions, I think we’re learning a lot.”

McCabe compares making these predictions to doing a jigsaw puzzle: Each bit of data about the ocean, temperatures, and algae is a puzzle piece that has to fit together with the others to offer a complete picture. The partnership hasn’t created enough bulletins yet to get meaningful data on how accurate their predictions are, but McCabe is keeping his own, informal tally. With the right combination of data, he says, “we have been pretty spot-on with our forecasts.”

Chris Funk, director of the Climate Hazards Center at the University of California, Santa Barbara, says that collaborations like these that incorporate data from many different disciplines and partners to give early warnings about climate dangers are going to be integral in responding to the effects of global warming. “The hope is that we can be proactive, as opposed to reactive,” he says. “We don’t need to just stop and think that climate change is just going to happen to us. We can go out and try to understand what it’s doing and mitigate those impacts.”

Trainer is hopeful that this partnership could be a model for other communities battling harmful algae. Another group is already forming in Alaska, where a different type of toxic algae is creating more blooms. And she hasn’t completely given up hope that scientists can find a way to get rid of the blooms entirely, using natural mechanisms like planting sea grass, which produces a bacteria that kills algae. But those solutions are a long way off. In the meantime, Trainer says, partnerships like this one can give communities a tool to handle one of the unexpected consequences of a warming planet. “Curiosity in science is going to benefit us as a human race,” she says. “I think this is one of the really good news stories of that.”

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