Tourist Trash Has Done Weird Things to Yellowstone's Thermal Pools
For over a century, tourists have discarded objects into the park’s hydrothermal features. Park staff try to remove as much as they can. But sometimes, the litter leaves a lasting impact.
In the 1880s, a visitor to Yellowstone National Park described how the churning waters of a pool not far from Old Faithful would suck a handkerchief down and return it “nice and clean” in a few minutes. Hundreds of visitors dropped their hankies into the warm waters of the Handkerchief Pool as it was known. The pool’s trick stopped working around 1927, and in 1929, a ranger removed kerchiefs, over 100 hair pins, a horseshoe and more from the pool.
Handkerchief Pool is no longer accessible by boardwalk, and tossing objects into hot springs is now illegal. But the problem of trash and debris in Yellowstone’s features persists, as does the park’s efforts to clean it up. This year’s inventory of stuff that’s been thrown, blown or dropped into Yellowstone’s features includes some oddball objects from golf tees to hotel keys and even a tiny copy of The Vampire Diaries.
“I think it’s a fascinating window into humanity,” says Margery Price, a geologist with the National Park Service. As of early October, she and other park staff have removed some 23,600 pieces of trash, 10,700 rocks and sticks and 369 hats from Yellowstone’s geysers, hot springs, mud pots, and fumaroles and the landscapes, boardwalks, and trails around them. This year’s tally set a record, though Price notes that may be due to more efficient collection practices. Common among the found objects are lens caps, pacifiers, and hair ties. Less common ones include dental retainers, rubber ducks, and fortune cookie fortunes.
“We believe that most of those are accidental,” Price says. Many objects are small, like junior park ranger pencils, and can easily slip through gaps in boardwalks. Other objects, such as tissues and food wrappers and even hats and sunglasses, likely fly away from their owners when winds rip through the treeless landscape.
(See 150 years of Yellowstone in these iconic Nat Geo images.)
This junk can damage delicate environments that take a long time to form, Price says. Large areas of the park have rock features made of a mineral deposit known as siliceous sinter, which grows centimeters—maybe even millimeters—in 100 years. And if debris ends up in pool or geyser, it can really cause problems.
“Every single thermal feature in the park is a result of a very complex plumbing system,” says Bruce Fouke, a geobiologist at the University of Illinois Urbana-Champaign who has done research and outreach in the park for 30 years but is not involved in the cleanup work. While some of the springs are tens of hundreds of meters in diameter, others are just a centimeter in diameter. Large or small, a web of tiny conduits below the surface brings water into and out of the features. “All that trash, it plugs up the plumbing system,” he says. Though natural, rocks and sticks can also block the water’s flow.
Debris also alters the chemistry of Yellowstone’s pools. In the warm waters, plastic garbage can shed microplastics and leach chemicals into the water. These added materials can impact the microbes that make their homes in the pools and give them their characteristic colors. For instance, microplastics can block the metabolism, the life-sustaining activity, of microbes that subsist on sulfurous compounds from Yellowstone’s volcano. Sulfurihydrogenibium yellowstonense bacteria make up some 98 percent of microbial life in some spots, Fouke says. “If you cut out that metabolic activity, it’s like going in with a hammer.”
Water flow, chemistry, and microbe changes can alter the appearance of water features. Morning Glory Pool was named in the 1880s for its blue color. By the 1950s, park staff started calling it the “garbage can.” Not long after, it was clear that the feature’s iconic color was in trouble. In the 1970s, rangers partially drained Morning Glory and removed as much trash as they could, but the clear blue color didn’t return.
Today, “it’s a totally different feature,” with orange and yellow hues, Price says. Trash, coins, and rocks into the hot spring, blocked the flow of hot water into the pool, lowering its temperature and encouraging more microbial growth. Just this year, a visitor told Price about coming to the park as a child and being encouraged by a tour guide to toss a coin into Morning Glory for good luck.
Coins are still a problem. This summer, the Yellowstone Geology team picked up more than $18.00 in coins. The pucks of metal can also mess with the hot springs’ chemistry and microbes. The warm waters normally hold little oxygen, which can be deadly to certain microbes, but metals can spur some microbes to produce oxygen, killing others and shifting the balance of the microbial community.
To help maintain the flow and chemistry of Yellowstone’s thousands of water features, Price and other park staff don protective gear and use their Earth science training to navigate the park’s hazards and remove debris. Often they use metal trash grabbers that range from a couple feet to 12 feet. But that doesn’t always do the trick, so the team has jerry-rigged longer tools including a window-washing pole with an attached grabber that can squeezed using an attached line of paracord. They also use a fishing rod with a three-pronged hook at the end to retrieve objects. “It doesn’t work for everything, but it is fantastic for hats,” Price says.
Given that more than 4.5 million people visit the park each year to gawk at its geysers, it’s surprising the trash troubles aren’t worse, Fouke says. “The Park Service has done such an excellent job of protecting the springs,” he says.
That has made Yellowstone a great place for research, Fouke says. Scientists suspect that life evolved in a hydrothermal environment that could have been similar to features in Yellowstone. Fouke studies Yellowstone’s hot springs for clues about evolution of life on Earth and what signs of life may look like on other planets.
Discoveries from Yellowstone have already left their mark on science and daily life. For instance, an enzyme discovered in hot spring bacteria enabled the development of polymerase chain reaction, or PCR, a technique used to make copies of DNA samples that ushered in a new era of biotechnology in the 1980s. Even our washing of clothes wouldn’t be the same without Yellowstone. Laundry detergents contain enzymes found in microbes dwelling in the park’s warm waters, Fouke says.
Keeping these areas clean is key to conserving these crucial members of the park’s fauna. “These are hallowed wilderness sites of microbes,” Fouke says. “And we’re not even at the beginning of fully comprehending all the things about these communities and how important they can be to us.”
