Is it true bacteria live in the soil? Isn’t that bad?

The greatest number of living creatures in soils is those you can’t see with the human eye. Although small, the activity of these organisms is vital for life as we know it. There are more microbes in a handful of soil than there are humans on the earth. Microbes, like bacteria and fungi, depend on soil for their homes-but it’s not all bad! These microbes decompose organic matter in the soil, returning nutrients to the soil that plants can use. They aid in the weathering of rocks and minerals which release important nutrients for plant growth.

Many fungi are important to the recycling of chemical elements that would otherwise remain locked up in dead plants and animals. Certain fungi are crucial in the decomposition of plant debris. They use carbon and energy that come from the breakdown of dead and decaying plants.

Bacteria are able to perform an extremely wide range of chemical transformations including degradation of organic matter, and nutrient transformations inside roots. These processes are crucial to growing a healthy food supply.

In general, bacteria are the organisms in soil that are mainly responsible for changing inorganic molecules from one chemical form to another, like nitrogen gas into ammonium. Other organisms, such as plants, may use some of the byproducts of bacteria’s “eating”. The bacteria gain nutrients and energy from these processes and provide other organisms with suitable forms of chemicals they require for their own processes.

There are millions of different types of microbes that live in the soil. Organisms that cause diseases like anthrax and listeriosis reside in soils. But, those “bad” bacteria live amongst the good bacteria, fungi and other animal life in the soil—which is called biodiversity. This variety of life in soil helps keep things balanced. Thus, most of the time, soil microbes are beneficial to human health, rather than being a threat.

-Answered by Mary Stromberger, Colorado State University

If you’d like to watch a video about a researcher who uses microbes to clean water watch here.

To learn more, view our SSSA Soils Are Living YouTube video.

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More educational materials can be found on various SSSA websites:

http://soils4teachers.org/  (K-12 Lesson Plans and Activities)

http://soils4kids.org  (Just for kids!)

http://soils.org/iys (International Year of Soils, with a coloring book and monthly ideas for teachers and scientists!)