Who does what: how do we figure out what microbes do in the environment?

Soil contains thousands of microbe types, each using different foods (substrates) to grow. When observed under a microscope, they appear similar, making it hard to identify them and understand their diets. While laboratory cultivation has helped microbiologists for over 150 years, many microbes cannot yet be grown due to unknown requirements. To study them in their natural habitats, scientists use a "toolkit" of techniques to analyze key molecules in cells, revealing which microbes are present and what they consume. Understanding these microbes is crucial for maintaining Earth's nutrient cycles and ecosystem health.