A mysterious disease is destroying stars and threatening critical ecosystems.
asserted
disease → destroy → ecosystems
Scientists are stumped, but they toil away in laboratories and distant, inhospitable environments, searching for an answer.
asserted
they → stump → answer
It’s not the plot of an interstellar sci-fi movie: It’s the groundbreaking science being done by a co-operative of marine biologists trying to save western North America’s sea stars.
asserted
It → ’ → stars
In 2025, Canadian researchers identified the culprit: star-killing bacteria called vibrio pectenicida.
asserted
researchers → identify → culprit
But the discovery only prompted more questions: Where did they come from?
asserted
they → prompt → Where
Why had the outbreak exploded so suddenly?
asserted
outbreak → explode → ?
Can anything be done to stop it?
asserted
anything → do → it
The outbreak of what came to be known as sea star wasting disease began spreading up and down the Pacific coast, from Mexico to Alaska, in 2013.
asserted
what → come → 2013
It devastated sea star populations, including wiping out almost 90 per cent of sunflower stars, the largest sea stars in the world.
asserted
It → devastate → world
“We lost over six billion of them,” said Alyssa Gehman, an adjunct professor at the University of British Columbia and a marine disease ecologist at the B.C.-based Hakai Institute.
asserted
Gehman → lose → Institute
It was Dr. Gehman’s team that made the breakthrough in August, 2025, identifying vibrio pectenicida as the cause of the outbreak.
asserted
that → make → outbreak
The bacteria essentially attack sea stars from the inside out, slowly liquefying their guts until they collapse into piles of goo.
asserted
they → attack → goo
While they are capable of sickening and killing all types of stars, the giant sunflower sea stars, which have dozens of limbs and can grow to the size of a bicycle wheel, were hardest hit.
asserted
which → sicken → wheel
It’s a slow, hideous death that has critical effects on both sea star populations and the ecosystems where they live.
asserted
they → ’ → populations
Sea stars are important predators in their communities that help to keep their prey populations in check – so important, in fact, that purple sea stars were the first to be called a “keystone” species.
asserted
stars → help → fact
The term is now used for the fragile predator-prey relationships that govern the lives of everything from Rocky Mountain wolves and elk, to sharks and seals, to lions and wildebeest.
asserted
that → use → lions
In the Pacific Ocean, sea stars eat sea urchins (among many other things).
asserted
stars → eat → things
Without enough sea stars, urchins proliferate and devour kelp and seagrass forests that are critical habitats for innumerable other species.
asserted
that → proliferate → species
Figuring out what was killing sea stars was a significant challenge.
asserted
what → figure → stars
Dr. Gehman’s team didn’t know at first whether it was a sickness, pollution contamination or some other cause.
asserted
it → know → ?
After proving the disease was transmissible from a sick animal to a healthy one, they tested whether contaminated water could be made safe by heat-treating it.
uncertain
water → prove → it
They found that it could, which suggested there was a pathogen they could kill.
uncertain
they → find → ?
When they did painstaking genetic testing to compare the gut biomes of sick stars with healthy ones, the team expected to find yet more complexity.
asserted
team → do → complexity
Instead, the data they got back were so clear the team wondered whether they’d made a mistake, and reran their tests just to be sure.
asserted
they → get → tests
They had found their villain.
asserted
They → find → villain
But finding the killer and stopping it are two different things.
asserted
finding → find → it
Because the contagion is a bacterium, they can grow it in the lab and more easily use it to continue testing, but many questions remain.
asserted
questions → grow → it
When they worked to isolate the pathogen, Dr. Gehman said, their tests subjected sea stars to doses of the bacteria that were universally lethal.
asserted
that → work → bacteria
This summer they’re testing to see whether there is, in fact, a survivable dose.
asserted
they → test → fact
If there is, it could suggest that some sea stars have or are capable of evolving a resistance to the disease.
uncertain
stars → be → disease
“There’s some hint that there is a low dose that they can survive,” Dr. Gehman said.
asserted
Gehman → ’ → ?
“So the question is: Is that genetically linked?
asserted
that → link → ?
And if it is, can we breed for that sort of increased resistance?”
asserted
we → breed → resistance
One of the team’s most surprising discoveries feels ripped from the script of Project Hail Mary.
asserted
One → rip → Mary
The seemingly unstoppable vibrio pectenicida does, in fact, have natural predators of its own: bacteriophages, or phages for short, viruses that attack bacteria by infecting them and reproducing inside them.
asserted
that → have → them
“That’s incredible, and has really kind of blown my mind to think about because that means vibrio pectenicida has a natural enemy that’s also in the system,” Dr. Gehman said.
asserted
Gehman → ’ → system
That knowledge could give sea stars a fighting chance.
uncertain
knowledge → give → chance
The team is now exploring whether the phages can be used to create a kind of natural antibiotic to help sea stars fight off the disease.
asserted
stars → explore → disease
“Hopefully, we can maybe use that superpower to treat them,” she added.
asserted
she → use → them
Dr. Gehman credits the discovery to a colleague at the University of North Carolina: Blake Ushijima, an expert in marine microbiology and microbial pathogens.
asserted
Gehman → credit → microbiology
…and 25 more, not listed.
