So a number of years ago our lab embarked on Project MERCCURI (let’s not talk about the tortured acronym). This complex and citizen science-based collaboration (website here) has been a fascinating journey. It’s ranged from getting to watch a rocket launch in Florida, to discovering/describing a new bacterial species, to our most recent publication… the microbiome of the International Space Station (ISS). This particular work, spearheaded by Dr. Jenna Lang formally of the Eisen lab at UC Davis, was such a simple concept at the start. We wanted to get 50-100 swabs from the ISS and conduct a 16S survey to see if there was any microbial biogeography to be observed on the station. At the time, there was only a single study, using 454 sequencing, that used culture-independent methods… and since they used vacuumed dust, the whole station was collapsed into one location.
We quickly hit a variety of snags. NASA said a max of 15 swabs which was far fewer than we hoped. Then came the news that the kitchen was off-limits (because it’s in the Russian module), then the news that the toilet was off-limits. So in the end we got our 15 swabs, collected from locations that were as analogous as possible to cell phones, shoes, and locations in earth homes.
Our publication on these swabs, “A microbial survey of the International Space Station (ISS)” just came out last week in PeerJ.
One of the biggest challenges has been to not make more of this than is there. The story received a fair bit of press attention, collected here, most of which was pretty reasonable. We had some of the usual problems about “germs” and “gross” (to be fair I used the word “gross” in the press release which was clearly a mistake). We had an unusual problem which is that a totally unrelated and unsubstantiated story about alien microbes (example here) happened around the same time and several times the two stories got mixed up. I even found myself quoted in an article about the alien microbes! But mostly we just had to keep telling reporters that this study, while interesting, was very preliminary and merely suggestive.
tl:dr The microbiome on the space station is distinct from, but resembles both homes and humans. Cool.
Modern advances in sequencing technology have enabled the census of microbial members of many natural ecosystems. Recently, attention is increasingly being paid to the microbial residents of human-made, built ecosystems, both private (homes) and public (subways, office buildings, and hospitals). Here, we report results of the characterization of the microbial ecology of a singular built environment, the International Space Station (ISS). This ISS sampling involved the collection and microbial analysis (via 16S rDNA PCR) of 15 surfaces sampled by swabs onboard the ISS. This sampling was a component of Project MERCCURI (Microbial Ecology Research Combining Citizen and University Researchers on ISS). Learning more about the microbial inhabitants of the “buildings” in which we travel through space will take on increasing importance, as plans for human exploration continue, with the possibility of colonization of other planets and moons.
Sterile swabs were used to sample 15 surfaces onboard the ISS. The sites sampled were designed to be analogous to samples collected for (1) the Wildlife of Our Homes project and (2) a study of cell phones and shoes that were concurrently being collected for another component of Project MERCCURI. Sequencing of the 16S rDNA genes amplified from DNA extracted from each swab was used to produce a census of the microbes present on each surface sampled. We compared the microbes found on the ISS swabs to those from both homes on Earth and data from the Human Microbiome Project.
While significantly different from homes on Earth and the Human Microbiome Project samples analyzed here, the microbial community composition on the ISS was more similar to home surfaces than to the human microbiome samples. The ISS surfaces are species-rich with 1,036–4,294 operational taxonomic units (OTUs per sample). There was no discernible biogeography of microbes on the 15 ISS surfaces, although this may be a reflection of the small sample size we were able to obtain.