In cities, it is hard to shake the sense that Homo sapiens are the apex participants; we rarely build anything with any other species in mind. And for Homo sapiens, it is also difficult to imagine “being” as anything outside the three pounds of brain matter, the core of consciousness.
But we are learning that our sense of the world – and who we are – has to accommodate another three pounds, deep in the gut. This is the “gut biome,” referring to the roughly 10,000 different microbial species living inside you. Some of these species are not yet identified, but by 2016 some have revealed that they may account for who we are just as much as our environment or our genes. By count, we may have more of their DNA in our bodies than our “own.”
These microbes may account for why we are fat, or depressed, or more anxious, or less anxious, or even more risk/accident prone. Who we are, then, is not a person, but a superorganism in which our “human” parts of us are in dialogue with quiet migrants who may well run the show.
To find out what’s in the gut biome, we can genetically sequence an individual’s poop. These are as individual as our genes or our fingerprints. Much of it comes from what we breathe and touch. So what is the gut biome of Brooklyn, or Tokyo, or Venice? Are they as individual as the people within them? How would we discover what they are? How would we represent them?
Our work – done with the generous support of the Mori Building Company of Japan – sets out to answer these questions. First, to detect the invisible world around us, and second, to bring that world to life. The videos we are generating are a landscape of these cities; the microbiological cities that do not build images of their own.
Our first obstacle was to reliably gather urban material to sequence. It is ambitious to pull microbes in from the open air. We had to find a way to get swabs from specific neighborhoods without depending on hundreds of volunteers with nylon swabs gathering microbes from sidewalks, gardens, and windowpanes.
We found, finally, extraordinary collaborators: urban honeybees. As citizen scientists, they gather microbial material within 1.5 miles of their hive, and always bring it back to the same place. We do not ask them to do anything different: we just ask to see what they have brought home. We ask this with genomics – some advanced computation – which breaks down the “bee debris” and allows us to see what the bees have gathered.
We are still learning. Along the way to learning what we are looking at, we are learning how to see from the microbes’ POV. It is a world almost parallel to our own; we move through it every day. If you look carefully, you will be able to make out human forms moving in the videos. From a microbial point of view, those humans are just another way to get to work.
As we get the lab data, we see that cities are different from one another in microbiology as surely as in culture, planning, and architecture. This may be why cities “feel” different, or why they thrive or die. We are only beginning to discover this new world, the one that has been at our fingertips all this time.
Shown here for the first time, our videos that are sketches from this new world. Whether they serve as postcards or maps, we hope they remind you of home.