Dirtland

Every time you walk on the ground you step on billions of microbes. Microbes live in the soil, on rocks, inside roots, buried under miles of Earth, in compost piles and toxic waste, and all over the Earth's surface. Microbes are found in boiling hot springs and on frozen snowfields. Microbes live in homes, in schools and on statues.

Millions and Billions of Microbes

Many millions of moving microbes make a mighty living munching manure in the soil. Each gram of soil may contain up to 1,000,000,000 or more microbes. That's as many microbes in a single gram of soil as there are people in all of China!

Rich Biodiversity

Not only are their many microbes in soil, there are many, many different species of microbes in soil. Some scientists estimate that each gram of soil may contain 10,000 different species of microorganisms! That's more biodiversity in one gram of soil than all the different types of mammals in the entire world. That's also more than all species of bacteria than have been cataloged (around 5,000)!

This section of the zoo includes many microbial habitats in addition to those found strictly in soil. These include compost, toxic wastes, hot springs, snow, and on statues.

Although we have grouped these microbes into "Dirtland," all microbes must be surrounded by water in order to live. However, a microbe can be surrounded by water less than 1 mm deep.

Some of the subsections of DirtLand include:

Ag Acres

Compost Pile
Many microbes convert organic wastes into useful compost.

Home Sweet Home
See what lives on your cutting board, on your shower curtain, in your couch and in your carpet.

Hot Springs
Some microbes can survive temperatures about the boiling point. These are called thermophiles.

House of Horrors
Visit monsters of the microbial world. See vampire bacteria that suck the life juices from other bacteria, Bdellovibrio, which gets inside other bacteria and eats their guts out, and fungi that strangle worms.

Ice Land
Some microbes live on snow and ice and die at room temperature. These are called psychrophiles.

Redox Mine Shaft
Some microbes, called anaerobes, "breathe" substances other than oxygen (nitric acid, sulfuric acid, iron, arsenic or uranium) to produce energy. They undergo different "redox" reactions.

Root Cellar
Microbes live near roots in the "rhizosphere" and they live in symbiotic associations with the roots of plants.

Statue
Some microbes slowly destroy stone buildings and statuary.

Toxic Waste Dump
Microbes thrive in chemical environments hostile to humans and remove toxins like oil and pesticides.

© 2000 Comm Tech Lab, Michigan State University. This work was created with support from the National Science Foundation and the Center for Microbial Ecology at Michigan State University. Current maintenance is supported by the Comm Tech Lab.