Pick up just a tiny bit of soil and you will discover a whole new world. Researchers have found that one pinch of soil may contain more than 30,000 protozoa, 50,000 algae, 400,000 fungi and billions of individual bacteria in addition to larger organisms like worms, insects and mites also live in the soil. These organisms break down dead plants and animals and recycle the nutrients into organic materials that enrich the soil. The movement of elements such as nitrogen, sulphur and phosphorus between different forms as they pass through the food chain. The elements cycle between gas forms and compounds which are found in soil and living organisms. For example, nitrogen cycle is heavily reliant on bacteria and involves the formation of nitrates (needed for making proteins which are the functional molecules in all organisms) from atmospheric nitrogen and then the break down of nitrogen compounds to nitrogen gas. The nitrogen cycle is an important part of soil formation and soil fertility.