The microbial community in the ground is as important as the one in our guts.
A small pine tree grown in a glass box reveals the level of white, finely branched mycorrhizal threads or "mycelium" that attach to roots and feed the plant. (David Read)
We have been hearing a lot recently about a revolution in the way we think about human health -- how it is inextricably linked to the health of microbes in our gut, mouth, nasal passages, and other "habitats" in and on us. With the release last summer of the results of the five-year National Institutes of Health's Human Microbiome Project, we are told we should think of ourselves as a "superorganism," a residence for microbes with whom we have coevolved, who perform critical functions and provide services to us, and who outnumber our own human cells ten to one. For the first time, thanks to our ability to conduct highly efficient and low cost genetic sequencing, we now have a map of the normal microbial make-up of a healthy human, a collection of bacteria, fungi, one-celled archaea, and viruses. Collectively they weigh about three pounds -- the same as our brain.