Title of Lab: Winogradsky Column Construction
Introduction
Purpose: to grow colonies of multi-hued microbes in a bottle in order to
study ecological succession in a microbiological community
Question: Under which conditions do various color bacteria thrive? What
type of bacteria are expected to grow?
Research / Background information: In the 1880's, a Russian
microbiologist named Sergei Winogradsky discovered that water mud
poured into a tall bottle and placed in the sun turned many different colors.
Many kinds of bacteria live in mud. He found that by adding a few simple
things, such as cheese or paper, he could control which colors appeared.
During the process of decomposition, all the oxygen near the bottom of
the container is used up. Red, orange and green bacteria that grow near
the bottom of the column are less tolerant or completely intolerant of
oxygen. They're photosynthetic; but they also get energy from hydrogen
sulfide, the gas that smells like rotten eggs. These oxygen-phobic bacteria
have crucial roles to play in the ecosystem. Some take part in the global
sulfur cycle. Others convert nitrogen into forms needed by plants. Neither
cows nor termites would enjoy their cellulose-based diets without the
helpful bacteria in their guts that digest the cellulose for them. Some
bacteria are decomposers that get nutrients by breaking down organic
materials things like the paper or grass clippings. Other bacteria are
photosynthetic and aerobic. Blue-green bacteria near the top of the mud
column use light, carbon from carbon dioxide, and hydrogen from water to
make carbohydrates and give off oxygen just like plants. The carbon
dioxide they need is released when the decomposers break down the
paper and grass clippings. The surface layer of the column may produce
an aerobic liquid air biofilm (pellicle) that can be sampled by dipping a
cover slip into the column and lifting a portion of the film from the water.
Procedure:
The following links will take you to various procedures. Choose the one
you like best. You can also search the net for additional ones.
http://www.exploratorium.edu/theworld/glow/grow.html
http://www.accessexcellence.org/AE/AEPC/WWC/1991/microbial.html
http://www.personal.psu.edu/faculty/j/e/jel5/biofilms/winogradsky.html
Constructing a Wynogradsky Column
assignment #
__1____
This analytic rubric is used to verify specific tasks performed when producing a lab report. If the task has been
appropriately completed, all points are awarded.
Rubric found at: http://www.howe.k12.ok.us/~jimaskew/evalab.htm
Category
Scoring Criteria
The purpose and question to be answered during the lab is stated.
Lab
Introduction
15 points
Research references used to prepare the lab are listed. Background
information about the column given
(There are always research references.)
The hypothesis is a tentative explanation and clearly shows it is
based on research. (Not just a wild guess.)
Procedures are written during pre-lab preparation and clearly state
what is planned written in such a way that others could accurately
duplicate the experiment.
(Write either a procedure or a method.)
Procedures
20 points
Measurements and calculations, when required, show proper units.
Observations (Write these as observations on the lab report.)
15 points
Data and observations of experiment are clearly recorded.
(State what happened in the experiment)
Summarize the essential lab data. Show how the essential data
answers the lab question. (Explain why the experiment happened the
way that it did.)
What could be done differently to enhance the experiment?
Explanation of what happened and the kind of microorganisms found
in the column. Discuss interaction between the microorganisms and
Presentation how they depend on one another.
20 points
Pictures
10 points
Score
5
10
5
10
Method is clearly written and explained.
There are no "understood" procedures.
(Such as: get out equipment or turn on gas.)
Conclusion
20 points
Points
5
5
10
10
5
10
A diagram of the essential apparatus used in the experiment is
drawn. (There is always something to draw.)
5
Pictures showing the set-up and development over time of the
column
20
Total Points Students are expected to honestly evaluate their own
work. If the difference between the student evaluation and the
teacher evaluation is more than 10 points, 5 points will be deducted
from the teacher's score when the grade is recorded.
100
Evaluation