Empire State Building, New York, Sept. 2013
Photograph by the author
If we were deprived of this microbial medium, we'd all die. Everything would die. These are the fundamental and essential conditions that life exists under and is supported by: a sea of life through which we constantly swim.
Any impoverishment of the environment can lead to issues. Killing off microbes protects us, to some extent, from disease; but the negative consequences can be disastrous. Polio, for example, was rarely a problem before the twentieth century. Poor water quality very nearly guaranteed that infants were exposed to it; for reasons yet to be fully understood, the virus has little effect on infants, so the virus-rich water supply conferred immunity on the majority of the population. It was only when water supplies were cleaned up that children began to reach young adulthood without immunity; the results were disastrous. Although cleaning up the water supply has bee a good thing in many ways, it is definitely possible to have too much of a good thing; and the steady pace of extermination of microbes in the child-rearing environment is leading both to a host of old diseases on the rise and new, emergent diseases.
The bottom line is that we need the microbial communities we inhabit. Cleaning them up too much, sterilizing the environment, turns out to directly affect the development and responses of our immune system, with sometimes disastrous results.
Although I'm sure it sounds like a reach, it's useful to think of the microbial environment we inhabit as an atmosphere. Like air, it invisibly surrounds us, and like air it's a medium that we absolutely require for daily life. We literally and figuratively breathe it in and out.
Interestingly, science has readily identified and embraced the chemical atmosphere of air and water as essential to the support of life, but the microbial atmosphere has been largely ignored, even though it comprises a living atmospheric medium for all larger life forms. Found in the air, soil, and water, one might argue that bacteria and fungi bridge the gap between the these chemical media and macrobiotic life forms. They are, seen from a slightly different but analogous perspective, a tissue that holds the macrobiota of the planet together by translating chemical constituents into usable forms.
So we live in an atmosphere of microbiota; and we depend on them so much that it becomes apparent symbiosis is, on the whole, a more prevalent lifestyle than competition.
This is so much the case that larger organisms don't juts host microbes; they go out of their way to create situations that favor the microbes they need for their own survival. More, quite literally, than meets the eye goes on in this regard; and we'll discuss that in the next post.