SubSoilsTitle

module_02 Effects of Submergence on Soil Properties
lesson_03 How does submergence change soil biology?
objective Describe the biological changes caused by submergence.

Soil: home to a grand diversity of organisms earthwormAerated soil contains tremendous diversity and quantity of organisms and microorganisms. Clicking the earthworm to the right will reveal a small sample of this diversity.

A biological transition of organisms Submergence starts a biological transition.  When oxygen in the soil is depleted, aerobic organisms die or become dormant.  They are replaced by two types of organisms surviving without oxygen called facultative and obligate anaerobes.  The transition from aerobic to anaerobic organisms takes a few hours to days. Following this transition, some aerobic microorganisms continue to live in the thin oxygenated zones discussed in lesson 2.

Organisms in submerged soil Do you know what  is the most common microorganism in submerged soil?  The majority of facultative and obligate anaerobes are specific types of bacteria.  They use chemical compounds and other soil substrates for respiration rather than oxygen.  Some types of protozoa and nematodes may also be present.

Next lesson In the next lesson, we can examine some of the changes in soil chemistry caused by the presence of anaerobic organisms.

Additional Reference If you would like to learn more about different types of soil organisms, this website contains several videos that may be of interest: http://www.agron.iastate.edu/~loynachan/mov/

 

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