Cave formation of stalactites and stalagmites in the Big Room of Carlsbad Caverns National Park, New Mexico. (Credit: © Michael Fitz - stock.adobe.com)
In A Nutshell
- A Temporary Food Web: In the cavern’s humidity, a dropped bag of Cheetos briefly fed mold, microbes and small invertebrates, though the park documented no change beyond that one patch of cave floor.
- Other Human Traces: Separate studies found different airborne bacteria on and off the visitor trail, along with algae and cyanobacteria growing under the Big Room’s artificial lights.
- The Rule Is Clear: To prevent contamination, litter and wildlife attraction, Carlsbad Caverns allows only plain, unflavored water in its caves, with exceptions for the underground snack bar and some medical needs.
A dropped snack bag can look like ordinary litter. In a September 6, 2024, social media post, Carlsbad Caverns National Park in New Mexico said a full bag of Cheetos had landed off the trail in the Big Room, North America’s largest single cave chamber by volume. The cave’s humidity softened the processed corn, which hosted microbes and fungi, and mold spread up nearby surfaces.
Cave crickets, mites, spiders and flies gathered around the spill. Park Superintendent Carmen Chapin told National Parks Traveler that staff first consulted the park’s cave specialist. A ranger then spent about 20 minutes removing the crumbs and the top layer of cave soil.
How Could One Bag Create A Food Web?
By concentrating scarce food in one damp patch. Without sunlight, plants can’t grow in a cave, so most cave food has to come in from outside. Water washes it in, or animals carry it in as droppings, eggs, debris or their own bodies when they die there. In some caves, microbes can also draw energy from chemical compounds in the rock and water instead of sunlight.
As the Cheetos softened, bacteria and fungi could feed on them, and small animals could eat the food, the microbial growth or one another. That linked decomposers (organisms that break down dead material) with the animals that eat them and the predators above those. The National Park Service lists three cave-cricket species at Carlsbad Caverns. It notes that the crickets, their eggs and their droppings are important food for other cave organisms.
Did It Change The Whole Cavern?
No, not based on the available evidence. The park reported no microbial sequencing, species counts or long-term monitoring. It described a temporary food web around one unusually rich patch of food, not a change across the cavern.
The park did say that some members of this short-lived community were cave dwellers, but many of the microbes and molds were not. It did not name which organisms were which or say how the outsiders arrived. The phrase “entire ecosystem” fits only at that small scale.
What Other Traces Do People Leave Underground?
More than crumbs. The park itself notes that every step a visitor takes into the cave leaves a fine trail of lint.
Researchers have looked for traces you can’t see. A 2014 study in Geomicrobiology Journal, led by U.S. Geological Survey researchers, sampled the cavern’s air in 2004 and 2009. In the 2004 samples, the most common bacteria grown from air along the paved visitor trail differed from those at off-trail sites. The molds Penicillium and Aspergillus were common in the underground Lunch Room, where food is stored, sold and eaten.
The study has an important limitation. In the 2009 samples, a family of bacteria called Enterobacteriaceae dominated along the descent trail and in the Lunch Room. The researchers said these bacteria could be natural cave residents or a sign of human contamination, and they couldn’t tell which. They suggested that park managers consider banning crumb-producing foods to protect the cave.
People have also changed the cave by lighting it. A yearlong study published in 2021 in Applied and Environmental Microbiology came from researchers at New Mexico Tech, the National Cave and Karst Research Institute and the National Park Service. They collected 120 samples from six sites in the Big Room between December 2016 and December 2017. The artificial lights fed growths of algae and cyanobacteria, known as lampenflora, along with other bacteria.
By the end of the study, visible growth appeared at all six sites, including the four that had been cleaned and had no established growth at the start. Light brightness, light color, surface type and earlier cleaning all affected these communities. The authors concluded that adjusting the lights alone may not stop the growth. The lighting study cannot measure the snack bag’s effect.
What Is The Practical Takeaway?
The practical answer begins with cutting avoidable inputs. Carlsbad Caverns National Park prohibits eating or drinking anything other than plain, unflavored water in any of its caves, except in the underground snack bar in Carlsbad Cavern. Visitors with diabetes or other medical needs may eat or drink on a limited basis. The park says food can contaminate the cavern, add litter and draw wildlife into areas it doesn’t normally visit.
That rule treats a dropped snack as an avoidable addition to the cave, even though lasting damage from any single spill has not been measured. The useful scale is the patch of cave floor itself. For organisms used to scattered, scarce food in the dark, one bag briefly supplied enough to link decomposers, consumers and predators before a ranger cleaned it up.
