Microbial Succession
as it Relates to the Study of Global Climate Change
Introduction:
 So why should we care about microbes?

 

Background information
(from the lab mentor, Darryl Martino)

Lab Description:
Study of Microbial Succession and Its Impact on Global Biogeochemical Cycles

The selection and development of sequential microbial populations in natural or disturbed systems is known as microbial succession. This succession occurs largely because the activities of initial populations of microorganisms bring about changes in their environment. These changes include decreases in available nutrients, alterations in pH or redox potential (Eh), disappearance of oxygen, to name just a few. The initial population becomes self-limiting due to the modifications of the environment which it mediated. At this point members of the population which were less dominant may find favorable growth conditions and emerge as the new dominant population. However, this population may soon further alter the environment leading to its own demise and to the emergence of still another different, dominant population.

In natural ecosystems these changes may be rather subtle and can go unnoticed. However, in the laboratory a variety of model systems can be established which clearly demonstrate succession of microbial populations and changes in the environment brought about by certain microbial groups. The Winogradsky column provides a very convenient model system for laboratory demonstrations of microbial succession. The column can be thought of as a miniature and easily manipulated ecosystem. The microbial population that is found in the column is a reflection of the conditions for growth within the column or ecosystem. Thus the population in any given system is a collection of those microorganisms which are adapted to or at least tolerant of the prevailing environmental conditions. Further, since these conditions are subject to change through time it can be expected that the microbial population will change in response to the selection pressures brought about by these environmental fluctuations. This series of labs is designed around the preparation and use of the Winogradsky column as a teaching tool to show microbial succession and the potential impact bacteria can have on global biogeochemical cycles.

Readings and References:
Madigan, MT, Martinko, JM, Parker J. 1997. Brock Biology of Microorganisms, Eigth Edition. Prentice Hall Publishers, Upper Saddle River, NJ.  Chapter 14, pp 533-605.

Where's Darryl?
From left to right:
John Scruggs
Mary Scruggs
Michael Lancaster
Denise Andrews
Michael Lowry
Darryl Martino
As a group of participants in the 1999 WWNFF Environmental Science Institute, we took part in the inquiry exercise described above to determine some of the effects of microbes on global conditions and change in climate. We conducted three experiments.  Click on each link below to view details of procedure, experimental treatments, and ways that you can modify these experiments for use in lessons for all grade levels.

Experiment 1: The Winogradsky Column
Experiment 2: Contact Slides
Experiment 3: Carbon Dioxide (CO2) Evolution From Sediments


Glossary of Uncommon Terms (terms that we needed help understanding!)

Additional Resources for Microbial Ecology
Environmental Science Links

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The Woodrow Wilson National Fellowship Foundation
CN 5281, Princeton NJ 08543-5281 - Tel:(609)452-7007 - Fax:(609)452-0066
Technical contact: lpt@woodrow.org