Curio: Microbial officemates and urbanites
Recent research has produced some interesting findings about the microbial “signatures” of the built environments of offices and urban spaces. But first, exactly what is a microbe and how do they have signatures? According to the US Centers for Disease Control and Prevention (CDC), a microbe is any organism too small to be seen with the naked human eye. Microbes come in two varieties--bacteria and viruses—and we live surrounded by them. They are literally everywhere—inside us, on our skin, and on every other surface around us. Most microbes are actually benign or even helpful, like the “flora” in our guts.
A microbial “signature” is the mix of microbe species that are found in a particular area. The area in question may be quite small (e.g., the rim of your coffee cup or the bottom of your shoe) or much larger (e.g., a train depot or a city). One interesting thing that research is showing is that a microbial signature can provide quite a bit of information about a location and who or what has been in that location.
One recent study of microbial signatures is by scientists at Northern Arizona University. In this small study, the researchers gathered data from office environments in three North American cities with different climates: San Diego, CA, (arid Mediterranean climate), Flagstaff, AZ (semi-arid), and Toronto, ON (humid continental). This study suggests that office environments’ microbial mixes correspond to the signatures of the wider geographic area in which they are located and not, as one might expect, similarities based simply on being offices or based on materials (e.g., carpet, wood, etc.) from which samples were gathered. In other words, samples gathered from offices within the three cities were found to peg the offices to those cities much more so than simply being office-type space. Further, location even mattered with respect to the micro-geography of the office. That is, the microbial make-up varied depending on whether the researchers’ samples were taken from the ceiling, walls, or floor. Samples taken from the floor were richer, microbially-speaking, than the other locations, and the scientists believe that this is because floors are the domain of human shoes, which pick up and transport a multitude of these minuscule hitchhikers. Another interesting finding is that the microbial composition did not vary significantly based on office building “climates”, i.e., the indoor temperature and humidity levels.
Another recent study was done by Cornell University researchers on microbial (and human) DNA on surfaces in the New York City subway. An interesting finding from this research is that, even several years later, a still-closed, Hurricane (“Superstorm”) Sandy-flooded subway station has a microbial signature that resembles a marine environment.
These two studies indicate that one could potentially discover, just from a microbial profile, where a material object has been or what has happened to it over at least some part of its history.
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Image source: lifeasahuman.com