Scientists took fungus samples from a model space habitat as a student crew lived and worked inside it for 30 days to determine how fungi populations change through the course of their stay. Microbiome

There’s a fungus among us wherever we go, even Mars, so scientists are studying fungi in space habitats to better understand how those microorganisms will affect astronauts on a mission to Mars or in a space colony.

They used an inflatable habitat with similar conditions to the International Space Station — although on Earth, it simulates the sort of closed system astronauts would live in on the moon or on Mars, complete with air filtration. As students occupied the habitat for 30 days, the researchers collected fungus samples to find species that were environmentally common as well as pathogens that could infect humans. According to their study in the journal Microbiome, the “fungal community” became more diverse during the course of the human habitation, “therefore, it is crucial to properly maintain a closed habitat to preserve it from deteriorating and keep it safe for its inhabitants.”

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The research took place alongside other studies of how humans react to a confined environment on a physical health level as well as on a psychological and behavioral level. Samples were taken from locations around the habitat throughout the length of the experiment. Some of the most abundant fungi collected were ones that are known to trigger allergies and asthma. And because previous research has shown that astronaut immune systems behave differently in space, the crew could face serious health risks. If stress leads to a decreased immune response in the space travelers, they could be more susceptible to a pathogen.

“Understanding the microbiome of a closed system and its association with human inhabitation will help to assess the correlation between human health and microbiome of the habitat,” the study says.

Cleaning procedures might be implemented as a safety measure during a colonization of Mars or another space journey, and indeed the researchers note that weekly cleanings in their model habitat included antibacterial wipes and could have affected the fungus samples they were able to collect.

But fungi tend to be hardy, so they present a challenge: “Fungi are extremophiles that can survive harsh conditions such as low nutrient, desiccation, high/low temperatures, acidic/alkaline, radiation, and other environments,” according to the research. “Fungal species not only have been isolated from all known environments on Earth, including barren lands like deserts, caves, or nuclear accident sites, but also are known to be difficult to eradicate from other types of environments including indoor and closed spaces.”

Even ones within the fungal community, known as a mycobiome, that are not known to cause deadly infection can be a problem. A report by journal publisher BioMed Central explained that one of the fungi collected is a common outdoor organism and while it does not often cause an infection in humans, it could trigger an asthma attack, particularly in someone whose immune system has been weakened during space travel.

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A protected habitat would be necessary for all foreseeable space missions because of the conditions on other planets and moons. Even if the Mars atmosphere was breathable, the air is too thin to support human respiration, even when it’s not choked with dust. And any water on Mars has long disappeared from the surface, putting another obstacle in the way of habitation.

The next step is to understand why the fungi populations in a closed habitat evolve the way they do.

“In-depth knowledge of the viable mycobiome will allow the development of required maintenance and cleaning procedures in a closed habitat … and also prevent it from deteriorating and becoming a health hazards to its inhabitants,” corresponding author Kasthuri Venkateswaran, from NASA’s Jet Propulsion Laboratory, said in the BioMed Central statement. “However, to be able to show that increased fungal diversity is a result of human presence, the mycobiome of the occupants will also need to be studied.”