Soil bacteria, SEM - stock photo

Soil bacteria. Coloured scanning electron micrograph (SEM). Bacteria in the soil are directly tied to nutrient recycling especially carbon, nitrogen, phosphorus and sulfur. Bacteria are a major class of microorganisms that keep soils healthy and productive. A teaspoon of productive soil generally contains between one hundred million and one billion bacteria. That is as much mass as two cows per acre. A ton of bacteria may be active in each acre. Bacteria make up both the largest number and biomass (weight) of any soil microorganism. Magnification: x4000, when printed 10 centimetres wide