Microbes Rule the World

Microbes make up 80 percent of all biomass, says microbiologist Carl Woese. In one-fifth of a teaspoon of seawater, there are a million bacteria (and 10 million viruses), Craig Venter says, adding, “If you don’t like bacteria, you’re on the wrong planet. This is the planet of the bacteria.” That means that most of the planet’s living metabolism is microbial. When James Lovelock was trying to figure out where the gases come from that make the Earth’s atmosphere such an artifact of life (the Gaia hypothesis), it was microbiologist Lynn Margulis who had the answer for him. Microbes run our atmosphere. They also run much of our body. The human microbiome in our gut, mouth, skin, and elsewhere, harbors three thousand kinds of bacteria with 3 million distinct genes. (Our own cells struggle by on only eighteen thousand genes or so.) New research is showing that our microbes-on-board drive our immune systems and important parts of our digestion.

Stewart Brand describes the state of our world, engineered by microbes and ourselves as the vehicles for their propagation in many cases.