The Winogradsky Column: an enclosed self sustaining microbial system.
Materials:
Mud or soil
Paper towels, finely shredded
Calcium sulfate (Gypsum or plaster of paris, craft or garden stores)
Calcium carbonate (garden lime or crushed limestone, garden stores)
Clean, clear plastic bottle with cap
water-either from the place you got the mud or distilled (not tap!) water for soils
Window or lamp
Procedure:
1. Mix 2 parts paper towels to 1 part calcium sulfate and 1 part calcium carbonate in the bottom of the bottle.
2. Add mud to fill the bottle about 25% of the way up and enough water to mix all the components.
3. Add more mud in on top of the bottom layer until the bottle is ~75 % full.
4. Fill the bottle with water to just below the neck and loosely cap.
5. Place the bottle in a window that receives sunlight or by a lamp. If using a lamp, make sure that the bottle is not so close that it gets hot.
6. Growth should develop in 2-4 weeks and continue to change over 6-8 weeks before becoming stable. Add water if necessary and the column should remain stable for years.
For a copy of these instructions in PDF format along with some additional information on how the column works, click here.
I was wondering how much CaCO3 and CaCO3 towards the column?
Hello, thanks for contacting me and finding the site. You need relatively little CaCO3, for a 1 L bottle, 0.1-0.5 g of CaCO3 is enough. If you want to experiment, you could set bottles up with the same source and different amounts of CaCO3 to see if there is an effect.
Is it supposed to cap tight the columns?
I would not make the cap perfectly tight. Sometimes you can get gas pressure build up. If you leave it loose, you may need to add water (distilled preferably) over time.
nice
why can’t tap water be used?
There are a couple of reasons. First, if your tap water is from a city, it has been treated and may still have some residual chemicals in it that are not in distilled (purified) water. Britta filters or similar can clean these up. Second, for soil, adding the purest water possible changes the system the least. It’s like adding rain. And that brings up an idea, I wonder what one established with soil and collected rain water would look like?
Prof. Hanson
Hi, I am making a column in my Microbiology class for extra credit. I saw in some other tutorials include an egg as a source of sulfur. Would you recommend this? Thanks.
Hi Emily,
Glad you found the site and good question! Eggs provide S from the protein in them. The shells are also mostly calcium carbonate, a good source of inorganic carbon for autotrophs. I might do the experiment where you use an egg vs. sodium sulfate and calcium carbonate. The eggs should enrich a different set of sulfate reducers and fermenting bacteria. The good part is that may influence the phototrophs that develop. The bad news, the other degradation products from proteins anaerobically are volatile fatty acids, some of which can be quite, um, fragrant; think cow or pig farm. However, these can also be used by groups like purple non-sulfur bacteria. In fact, they are being used for treating these types of waste.
Best,
Prof. Hanson