Feet smell like feet and armpits smell like armpits because they each harbor unique species of bacteria with unique metabolisms that produce unique volatiles. Human skin is covered in a patchwork of many different microbes and microbial communities, collectively known as the microbiome, a layer of our bodies that is still very poorly understood. Research initiatives like the Human Microbiome Project aim to catalog and characterize the species of microbes living on different body parts or in our gut, to better understand the role they play in health and disease. Maps showing the composition of the communities on different body parts begin to show the complexity of this microbial organ.

Artist Sonja Bäumel explores the skin microbiome in her project Cartography of the Human Body. Bacteria isolated from Bäumel's skin were characterized and grown individually, then used to reconstruct an artificial microbiome with many layers of differently-colored species. Giant petri dishes grew imprints of the new microbial layer, creating a living snapshot of the normally invisible bacteria.

Cartography of the Human Body, by Sonja Bäumel

The Textured Self, by Sonja Bäumel

Bäumel's background is in fashion design, and some of her other works translate the invisible microbiome into a tangible layer through incredible hand-crocheted and knitted pieces. The Textured Self represents the amount, color, and shape of microbial colonies isolated from different parts of her skin, knitted onto a life-size silhouette. Her master's thesis project, (In)visible Membrane, imagines if the invisible layer of our microbiome could become visible, responding to our body temperature and producing materials in the cold places where we need them most. Her project is made up of several parts that "mediate between science and fashion, science and art, between facts and imagination, between body and clothes."

Invisible Membrane, by Sonja Bäumel

Science and art can help us better understand our microbes, making them visible and tangible, exploring their smells and their chemistry, how they work with each other and with us.