Every gram of a typical healthy soil is home to several thousand different species of bacteria. One square metre of soil can contain about 10 million nematodes and 45 000 microarthropods (springtails and mites). It has more species in it than 1 km2of rainforest. In addition to bacteria, soil is home to microscopic fungi, algae, cyanobacteria, actinomycetes, protozoa and nematodes, and macroscopic earthworms, insects and the occasional wombat.