7 wonders of the soil
A spoonful of soil can contain as many as a billion bacteria. We often think of them as ‘germs’, but these single-celled organisms are crucial to soil and human health. Different kinds do different jobs. One important group, actinomycetes, is helpful in a multitude of ways: decomposers break down such tough materials as tree bark and are responsible for that freshly turned earth smell. Frankia sp., the nitrogen-fixing actinomycetes, work with nitrogen-fixing host plants to accumulate atmospheric nitrogen, which plants can’t use in its gaseous form. This symbiosis allows the plants to thrive while building nitrogen-rich soil in which other plants can grow. And it was an actinomycete bacteria that provided us with streptomycin, the first-ever antibiotic remedy for tuberculosis, isolated by Dr Albert Shatz in 1943. We still use these bacteria today to produce antibiotics such as erythromycin and tetracycline, proving that our obsession for killing ‘all known germs’ with disinfectants may be somewhat misguided!