WINOGRADSKY WRITE-UP INSTRUCTIONSI know that you’ll likely (and justifiably) be lounging around in yoga or sweat pants this weekend
but soon after you’ll need to get started on writing up your Winogradsky column
experiment. The report you write should be in a typical format for primary scientific literature
which means that there should be an Introduction, Methods, Results and Discussion section. I
am including an example paper as an attachment. The introduction section gives the
background of the work done to date and why it is scientifically important (why do we care
about it and what has been done in the past). It wraps up with what still remains to discover and
how your work may answer that question (justification for your work). Some history of the
experiment provides a good setting as well. The methods section describes exactly what you did
which includes setting it up, monitoring and data that you gathered. This section should be
detailed enough that someone reading it could duplicate your work (one of the important aspects
of science since experiments and potential results should be repeatable for verification). The
results section should include a summary of the information you recorded during the
experiment. It usually includes visuals like charts, graphs, tables or even photos. Your report
should include at least 3 photos of your column including the beginning conditions, sometime in
the middle and then at the end. It should also include a table or list of your observations through
time and changes that you noted. In the discussion section, you should discuss the importance of
your results (biologically). Results are “just the facts” while the discussion puts them in context
both within your work and then within the larger picture in terms of what is known about that
topic. Make sure to include a schematic/drawing of your column and what bacteria populations
were found in each layer. Lastly, the discussion section should include a description of anything
odd that occurred and some reasonable suggestions why they may have occurred (the reason
behind the data recorded is the theme for this section). Describe the bacterial populations that
exist in each layer and why they are found there (e.g. their biology). You can also suggest what
you would do differently if you were to run the experiment again (interesting aspects that you
would pursue or how you would change the experiment to get better results if you didn’t get
any).
I’m happy to look at rough drafts prior to the due date so don’t put this off to the last
minute! Please look over the rubric on the Winogradsky assignment page in Canvas for more
details and scoring.
Dr. C
WINOGRADSKY COLUMN FOR OBSERVATION OF A BACTERIAL
PHOTOSYNTHETIC COMMUNITY
A Winogradsky column is an apparatus that allows scientists to observe changes in a bacterial
photosynthetic community over time. Like all communities, bacterial communities change over time in
response to environmental conditions. The Winogradsky column makes an ideal ecological learning tool
for students because students can visually see color changes over time demonstrating an ecosystem in
flux. The changes in color represent the growth of various bacterial species that photosynthesize using
different pigments for the process of absorbing light energy. Analysis of the micro-organisms present
demonstrates the cycling of nutrients in an ecosystem and the dependence of the various species in a
biological community on each other for their nutritional requirements.
To establish the ecosystem, mud from a water source is placed in a clear bottle along with autotrophic
and heterotrophic carbon sources and a sulfate source. The system is placed in a lighted area and left to
grow. Observations are made over a period of weeks.
Hypothesis
Refer to reference #3 below and develop a hypothesis regarding what you expect to see in your
Winogradsky column after several weeks.
Materials
One clear-sided plastic bottle – a minimum of 15 cm in height and 5 cm in diameter (a plastic water
bottle or a clear tennis ball container work well). You will need a mouth size large enough to pour
mud into.
Bottle cap or plastic wrap and a rubber band (if you cut top off) – to seal top and prevent water loss
Sulfate source – egg yolk about 1% by weight of soil. Sulfate serves as an electron acceptor for the
electron transport chain in the absence of oxygen.)
Carbonate source – chalk, limestone, or baking soda about 1% by weight of soil. This provides carbon
dioxide for photosynthesis.
Cellulose or starch – white paper towels, newspaper, grass clippings or cornmeal, oatmeal, etc. This
provides a carbon source for the anaerobic chemoheterotrophs at the bottom of the bottle. These
bacteria initiate the sulfide gradient necessary for the photosynthetic micro-organisms.
A stick or spoon for stirring
Light source
Mud from a pond or edge of a stream (This is important; mud from the edge of a pond or stream.)
Water from pond or stream
Instructions
1. Wear gloves to collect soil sediment. Break up clumps and remove any large pieces of debris.
2. Add egg yolk and carbonate source to mud, and stir to mix.
3. Pour 2 – 3 cm of the mixture into the bottle. (If using a plastic water bottle you can cut off the
top part and invert to use as a funnel.)
4. Add the cellulose or starch to the mud in the bottle and stir, mixing the cellulose into the mud
mixture. If using paper, shred into small pieces 2 -4 cm in length. The slurry should be about
the consistency of a milkshake. Use about 1 paper towel per cup of mud.
5. Continue to add more mud mixture 2 – 3 cm at a time. (Mud mixture only, no cellulose or
starch here.) Tamp down with each addition of mud to remove trapped air. Try to eliminate
any air pockets in the layered mud.
6. When about 5 cm from the top of the bottle, stop adding mud. (You should have a minimum of
about 12 cm of mud in the column.)
7. Pour 2 – 3 cm of water over the mud.
8. Seal the top with the cap or plastic wrap to prevent loss of water.
9. Wash your hands.
10. Place the bottle near a light source. If possible, place about 60 cm (2 feet) from a continuously
lit light source of 40 – 60 watts. (If you use an incandescent bulb, you want to be sure that the
bottle doesn’t get too hot.)
•
Alternatively, you can place near a brightly lit window (although growth of photosynthetic
bacteria will be slower).
•
Do not place in direct sunlight (again, to prevent overheating). However, if outside
temperature is 70 o F or higher, you can place column outside in the shade. (The column
will begin to stink after a week or so, so outside is good.) Be sure that the shade is a bright
shade, as the bacteria in the column require light for photosynthesis.
Data collection
Examine the column weekly for a minimum of eight weeks (ten weeks is better).
1. Take notes describing what you see each week and the changes that have occurred.
2. Take a picture each week so you have visual documentation of the changes. You must include at
least 3 photos of your column progression.
3. Create a data table that includes all of your observations.
Analysis
1. Try to identify the type of bacteria growing in your bottle at the various regions using the
references below.
2. After identifying the bacteria, draw a schematic of a column. Identify areas on the schematic of
chemoheterotrophic and photoautotrophic growth, and areas of anaerobic and aerobic growth
in your bottle.
3. For each of the bacterial species identified, describe the metabolism of each, why it is found in
that region and how it affects its environment in the column.
4. Show on your schematic the cycling of carbon and sulfur in the ecosystem of your bottle,
identifying the chemical compounds in which they are cycled.
Conclusion
Refer to your hypothesis and in light of your analysis, compose a conclusion that addresses your
hypothesis. If you did not observe what you expected, identify possible reasons that explain why.
Explain what you might have done wrong or would do differently if you were to repeat the experiment.
If you grew 2 or fewer species, compare your results to the expected diversity of species and discuss the
biology of the species you did not see as well.
Submit your report
Your report should include:
1. Title
2. The purpose/history of the column
3. Your hypothesis
4. Methods and materials – a brief description of what you did in your own words (NOT a verbatim
repeat of the instructions)
5. Data
a. Your weekly notes
b. A summary of the changes that have occurred over the time period that you have
observed the column
c. Photos – minimally, beginning and ending photos
d. Data table
6. Analysis
a. Your identification of the types of bacteria growing at the various levels in your
Winogradsky column and their biology
b. Your schematic diagram showing the ecological relationships in the bottle and the
cycling of nutrients
7. Conclusion
References
1. Movie demonstrating how to make Windogradsky column –
http://quest.arc.nasa.gov/projects/astrobiology/fieldwork/lessons/demo.html
2. Animation demonstrating Windogradsky column and the types of bacteria growing in the
column – http://www.sumanasinc.com/webcontent/animations/content/winogradsky.html
3. Discussion, with pictures, of the types of bacteria growing in a Winogradsky column –
http://www.biology.ed.ac.uk/research/groups/jdeacon/microbes/winograd.htm
Notes
1. Column will begin to stink after a week or so. This is normal. It is caused by the production of
volatile compounds from anaerobic respiration by the bacteria in the column.
2. Do NOT let the column dry out. Add more water to the top, as needed.
3. Cracks will appear in the sediment in the column after a couple of weeks. This is normal. It
indicates that the column ecosystem is changing. The bacteria in the column are producing
gases that are taking up space causing the cracking.
4. Use a bright light (e.g., bright sunlight or fluorescent light) to visualize the colors in the column.
The colors can be subtle.
Winogradsky Column Lab
Introduction: The Winogradsky column is a miniature, enclosed ecosystem that is used for
enriching sediment microbial communities. Developed in the 1880s by Sergei Winogradsky, the
column provides numerous gradients from which the variety of organisms can grow. This allows
the enrichment of the microbes, sediments, and the soil within the lab. Meaning specific types
and forms of organisms can be grown to vastly larger population sizes, which means they can be
studied and understood more efficiently. The Winogradsky column is significant because it
allows the cultivation of microorganisms effectively, which contributes to the further study of the
ecology.
Hypothesis: For my hypothesis, I predict that multiple layers along with multiple
microorganisms will form within the column. Aerobic organisms will form as there is enough
oxygen for them to use, and anaerobic organisms will form within the layers of sediment that
will soon form.
Methods: To begin my experiment I gathered enough mud from a local stream to fill up a large
cup, along with a cup size water sample from the stream. Then I added a sulfate source(egg yolk)
and a carbonate source(baking soda) to my mud, stirring until it was well mixed. I then poured
this mixture into my empty water bottle filling about 3cm worth of it up. After that, I added my
cellulose source(paper towel) to my water bottle mud mixture. I did this by ripping up my paper
towel into 3cm pieces and pushing them into my mud until I had a milkshake-like consistency. I
then filled the rest of my water bottle with the remaining mud mixture until I had 5cm of space
left in the bottle. I then added 3cm worth of my stream water to finish off the column. I covered
my bottle with plastic wrap and used a rubber band to secure it. Finally, I placed it in an area
where it will receive sunlight as well as shade.
Data:
Week 1
Slight Odor, slightly more
water at the top of the column
Week 2
Strong Odor, sediment is
beginning to separate, more
water at top of column
Week 3
Odor, different colors than
before are being shown,
possible growth of organisms
beginning
Week 4
Odor, needed to add more
water as it was getting dry,
beginning to see moving
organisms, sediment layers
visible
Week 5
Odor, Layers of sediment are
far more visible organisms
are moving throughout
column
Week 6
Odor, mold-like substance
forming near the bottom of
the column
Week 7
Odor not as bad, organisms
still visible along with new
colors throughout column
Week 8
Multiple organisms have
grown, along with 3 different
types of sediment layers it
seems. Multiple colors green,
brown, red, grey.
Analysis:
Conclusion:
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Formatting
Title Page
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