Ecologists group large geographic regions with similar environments and distinctive plant and animal communities into biomes. The environmental factors influencing biomes include latitude, the general climate and topography of the region, and soil. Soil is the foundation of every terrestrial ecosystem. Each biome has soils with characteristics unique to it.
Forests occupy nearly a third of Earth’s land surface-they are the most complex and diverse ecological system. The forests we like to hike in are beautiful because of their trees. But, it’s the soil that keeps those trees healthy. Soil provides the nutrients for the trees to grow, and the support to hold the trees up…even a giant redwood! If a forest is destroyed in a fire, the soil will bring back life.
Soils are an integral structural part of your woodland and the larger forest ecosystem. Important forest soil functions include:
• Providing water, nutrients, and physical support for the
• growth of trees and other forest plants
• Allowing an exchange of carbon dioxide, oxygen, and other gasses that affect root growth and soil organisms
• Providing a substrate for organisms linked with vital ecosystem processes
• Harboring root diseases and other pests
• Affecting water quantity and quality
Soils and our Lakes, Rivers, and Streams
Water covers about 75% of Earth. This makes aquatic biomes the broadest of the biome groups. Aquatic biomes are further categorized into freshwater (rivers, wetlands, streams, lakes, etc.) and marine biomes (coastal wetlands, deep sea, etc.) Soils in the forest, our wetlands, or the plains affect the water in streams. All soils clean and capture water, affecting both water quality and quantity. Every drop of water we drink traveled through soils at one time or another. The soils helped purify it along the way.
Without soil and soil particles, water would be running on bare rocks! When it rains, the soil acts as a sponge, soaking water into the ground. From there a few things can happen to the water. The water can be taken up by plants, microbes, and other living things, or the water moves into the underground aquifers and lakes, and flows into streams before eventually making it to the ocean. If rainfall contains harmful pollutants, the soil acts as a filter; contaminants are captured by the soil particles, and the water comes out cleaner in the aquifers and rivers.
Soil filters water as it moves from the land surface into the groundwater. This occurs through physical, chemical and biological process. For example, septic systems rely on these processes to protect groundwater quality as well as maintain the quantity of our water supply. When soils are not protected, soils and nutrients can pollute water, washing away into streams and oceans.
No matter where you live, there is soil under your feet. And it is a resource we need to protect, because soils sustain life.
Read more about soil biomes in Part 2 of this series.
-Answered by Tom Fox, Virginia Tech
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To learn more, view SSSA’s Soils Protect the Natural Environment video.
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!)