Sergei Winogradsky was a Russian scientist who created this miniature environment for studying microorganisms in the late 1800s. Once these columns are created they can be stored for several months and used for a variety of laboratory activities for all grade levels (Fox 2010).
Materials:
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Gloves
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Buckets
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Hand Trowels/Shovels
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Water Shoes (or old sneakers that will be thrown out after activity)
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Observation/Data sheets (to be attached to interactive notebooks)
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Aprons (or disposable ponchos)
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Empty plastic bottles (12 to 20 ounce)
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Spoon for stirring
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Carbon source (shredded newspaper)
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Sulfur source (hardboiled egg yolks)
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Water (obtained at source)
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Soil (obtained at source)
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Rubber Bands
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Plastic wrap
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Procedure:
Soil samples for Winogradsky Columns can be obtained from any location however, those obtained from a water source are best. In this activity samples will come from the estuary environment of Long Island Sound just below the low tide line better to get from salt marsh pond mud (Subtidal Zone). Choose a location where students can easily access samples and where there are no restrictions for use. (Avoid Wildlife Sanctuaries and private property).
Upon arrival at the Subtidal Zone find a muddy spot that, preferably, does not have many rocks. Using buckets, gather mud (enough to fill each student's plastic bottle about 75% full) being careful to avoid rocks, sand, and sticks. Gather a small amount of water from the same location (students need only a few centimeters of water at the top of their plastic bottles above the mud).
In a separate location, such as picnic benches at the gathering site or back in the classroom lab, prepare individual Winogradsky columns in plastic bottles. First mix in about a handful of shredded news paper and a tablespoon of egg yolks for every two bottles that will be filled with mud. Add a little more water if the mixture is too thick. Have students fill each bottle about three quarters full of mud mixture, gently tapping down mud after each spoonful to keep air bubbles out of column. Then add about one quarter inch of water to the top (don't stir it in). Cover top of each bottle with plastic wrap and fasten with rubber bands. Place in indirect light at room temperature. After about three to six weeks the different layers of microorganisms will become visible. Columns are now ready to be used for observations. Take caution when removing plastic wrap from the column. Always do all unwrapping and gathering of specimens under a fume hood to prevent inhalation of sulfur gases. Top off column with water lost due to specimen removal or evaporation. Rewrap the column with plastic wrap immediately after removing specimens.
In a Winogradsky column different organisms will develop in different layers depending on their individual needs for oxygen, sulfur and sunlight. Layers in individual columns will vary depending on the water source, amount of light, temperature and nutrients in the mud.
Below is a sample of how the layers form. At the top where the sunlight can penetrate the photosynthetic organisms can thrive. This is also the area where oxygen is present due to the production of O
2
from photosynthesis. Therefore, as the amount of sunlight decreases, so does the amount of oxygen. As the sunlight and oxygen decrease the sulfur content increases. In these layers the sulfur producing organisms are present.
It is important to note that a Winogradsky column is not a true representation of the natural ecosystem. It serves as a mini laboratory to obtain specimens for study which can be a useful tool in the classroom.
The diagram below is an example of how the layers can form in a Winogradsky column, will not all form exactly alike. Most, however, will have distinctive zones usually identifiable by colors or odors. This will make is easier to identify the individual types of bacteria and other microorganisms.
Layers of a Winogradsky Column: