The mysterious dog-killing bacteria plaguing a popular national park

Zion National Park is one of the natural wonders of the country, if not the world. In eastern Utah, the park is the 10th most-visited national park according to the National Park Service (NPS), and throughout the pandemic it has continually struggled with overcrowding, with many hikers flooding in to cram onto one particular hiking trail: the Narrows.

The Narrows, aptly named, is the narrowest part of Zion Canyon. Walking through it involves splashing through the Virgin River, surrounded by massive rock faces on either side.

But a few weeks ago, the park was forced to warn visitors against the Narrows along with another popular hike, due to toxic bacteria spreading through the park’s waterways.

In a statement, the NPS wrote: “Toxin-producing cyanobacteria have been detected in the North Fork of the Virgin River, which will remain on an advisory notice.” It added: “During Health Advisory and Watch advisories, reenactors should avoid primary contact reenactment such as swimming or head submersion. During Danger announcements, reenactors should consider avoiding all direct contact with water.”

This is not the first national park or national recreation area to face a water problem. Earlier this year, 202 visitors to the Grand Canyon fell ill with norovirus, which lived in warm river water, and the Everglades have constantly fought with algae blooms, also known as red tides.

And even more surprising is that this is not the first time that bacteria have forced the Narrows to close. Two years ago, a dog died an hour after swimming in the river and “biting” algae growing on the rocks. He was unable to walk and was having seizures before he died, McClatchy News previously reported.

Dr. Kate Fickas, an aquatic biologist who worked with the US Geological Survey in Zion two years ago when it first emerged but now focuses on South Dakota, said they were initially puzzled by what had caused the death of the dog.

“Often, dogs just drink water too fast, so we thought it was just that,” he said.

However, after testing, they found the water contained cyanobacteria, commonly known as blue-green algae, the same results the park discovered just a couple of weeks ago.

It’s not at all weird. Dangerous blue-green algae blooms sprout across the country during the highest temperatures. Take the Great Lakes, for example, where harmful algae blooms are a common occurrence. At the beginning of this year, the new scientist reported that harmful algal blooms are becoming more common around the world.

Environmentalists are concerned, arguing that the large number of national parks with damaged water sources leaves many unanswered questions. “More than half of the national parks have waters considered to be impoverished” under the Clean Water Act, Sarah Gaines Barmeyer, assistant vice president for conservation programs at the National Parks Conservation Association, told The National Park Traveler, citing pollution. coming from outside the parks as one of the main causes of deterioration of water quality.

However, there are a few things that make the algae in Zion a stranger case than most. The first is that algal blooms most commonly occur in lakes, large bodies of standing water; but in this case, an algae bloom occurred in a river.

“Algal blooms don’t happen often in rivers,” says Fickas, adding that they “especially don’t happen in virgin rivers.”

One of the biggest causes of algae blooms is runoff from fertilizers in nearby towns. When a large body of water doesn’t disperse these organisms through movement, they accumulate and that’s when you end up with blooms. In Zion, this is not a possibility, so scientists knew that this algae was a bit out of the ordinary.

“So we started to hypothesize that the algae were benthic,” Fickas said. Benthic cyanobacteria differ from typical algae in that they live closer to the bottom of the water body, rather than floating on the surface. It also implies that algae have always been a part of the river, simply not flourishing or undetected, and have historically become a source of health concern.

As to what is causing them to bloom two years ago and just a few weeks ago, scientists have a few theories, although not much research has been done on the subject.

“An increase in water temperature would be problematic in theory,” says Dr. Don Bryant, emeritus professor of biotechnology at Pennsylvania State University. “This problem would be greatest in the summer and in any dry season, which of course is ongoing now in the West.”

Another theory, according to the park, suggests that high flow events could trigger rapid regrowth. A Zion spokesperson said: “National Park Service scientists have observed that high flow events (for example, spring thaw or flash flooding) remove cyanobacteria. After high flow events, park scientists have observed that cyanobacteria regrow in subsequent weeks and months.”

But determining the cause of the bacteria is only half the battle, of course. And while the bacteria will likely be difficult to get rid of, according to Bryant because it’s part of the river’s natural flora, the National Park Service is instead turning its attention to ongoing sampling and testing, as well as alerting the public through various media.

In a statement to The Daily Beast, a Zion National Park spokesperson described their efforts.

“In partnership with the Utah Department of Environmental Quality (Utah DEQ) and the Utah Department of Health and Human Services (Utah DHHS), we issue health advisories so guests can make informed decisions about recreation at the park. We share updates about cyanobacteria on our park website, in social media posts, and in person at park visitor centers, on trails, and in chats with rangers. In all of these updates, we remind visitors not to drink or filter the water from the North Fork of the Virgin River, La Verkin Creek or North Creek.”

But Bryant’s take is that reenactors shouldn’t worry too much. At least not yet. “One of the most interesting things to think about,” Bryant said, “is that a lot of the bacteria that we’re finding has always been there. We have become more diligent in testing them and telling people where it is safe to swim.”

“I’ll put it this way,” Bryant continued. “I grew up swimming in lakes and ponds, and I don’t think much has changed in them. But would I swim in them today knowing what I know now? Absolutely not.”

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