For many Earthlings, our planet is teeming with airborne pollens, spores, and toxins that clog schnozes and turn windpipes wheezy. Sadly, jumping to space rocks may not help, a new NASA study suggests.

In a 30-day simulation of living life on another planet, NASA researchers found that fungi followed artificial astronauts and set up their own colonies. Many of those small space explorers excel at surviving in extremely harsh conditions, such as those in the salty, acidic high-altitude soils of the Indian Himalaya or the radioactive remains at Chernobyl. And several of the fungi that piggybacked off-world in the simulation are associated with allergies and asthma indoors, the researchers report this week in the journal Microbiome.

“The statement ‘wherever humans go, microbes hitchhike along with them’ is true for fungi also,” Kasthuri Venkateswaran, lead study author, told Ars. He works in the Biotechnology and Planetary Protection Group at NASA’s Jet Propulsion Laboratory. “At present, most of our studies have been conducted to know the dynamic changes regarding bacteria , not fungi,” he notes. “This is the first study that examined the fungal changes in a confined environment for at least 30 days of human habitation in isolation using molecular methods.”

The NASA simulation is just the first step toward understanding what the fungal worlds—mycobiomes—of our future space colonies might be like. But, so far, mycobiomes seem to be worth monitoring in the future. In addition to causing respiratory problems and allergies, fungi can cause infections and hasten the deterioration of materials.

Microbial migrants

For the trial, Venkateswaran and his colleagues had three students spend 30 days in a 12-by-10-by-2.5-meter inflatable lunar/Mars analog habitat, or ILMAH. During the trial, the ILMAH was a closed system, with little exiting or entering beyond air and the samples (through an airlock). Four times during the 30 days, the students cleaned the habitat and swabbed eight locations within the ILMAH, at days 0, 13, 20, and 30. Outside, researchers collected the swabs and tried growing and sequencing genetic material of fungi from the swabs. In the end, they cultured 117 fungal isolates and got sequences from 113 of them.

Across the time points, the researchers saw the sheer amount of fungus they picked up decrease, but diversity—the number of different types—increased. Fungal levels may have increased prior to humans moving in and were then squashed or elbowed out by more human-associated fungi.

Over time, species from the genera Epiccocum, Alternaria, Pleosporales, Davidiella, and Cryptococcus increased. Epiccocum and Alternaria, part of the Pleosporaceae family, were also the most abundant. They are common household molds that can colonize human bodies and produce toxins, volatile organic compounds, and enzymes that can irritate airways.

The researchers also found small increases in Cladosporium members of the Davidiellaceae family and in Aurobasidium members of the Dothioraceae family, some of which can survive in extreme conditions, like the ice of Antarctica. These fungi may feel right at home on whatever new planet they find themselves on.

“The results of this study revealed that the overall fungal diversity in the closed habitat changed during human presence,” Venkateswaran and his colleague conclude. Understanding those changes will help inform cleaning and maintenance strategies in future habitats to avoid hazards.

Microbiome, 2017. DOI: 10.1186/s40168-017-0280-8 (About DOIs).