In the 1880s, Russian microbiologist Sergei Winogradsky sealed pond water, mud, and nutrients in a clear tube. The column gave rise to a diverse mix of pond bacteria, which organized into layers based on their energy sources: carbon, hydrogen, sulfur, or oxygen. With different species recycling different nutrients, Winogradsky realized, the microbes collectively formed a self-sustaining ecosystem.
The American Museum of Natural History in New York City is reviving this microbial experiment by displaying a 6-foot-tall Winogradsky column through August. It’s part of an exhibit called The Secret World Inside You, which explores bacteria found in our bodies. Just as pond bacteria colonize distinct layers in the column, bacteria in our guts colonize distinct parts of our stomach and intestines to help us digest food. “The human digestive tract is one huge Winogradsky column,” says Rob DeSalle, an evolutionary biologist who helped curate the exhibit.
Can’t make it to New York to see the exhibit? No problem—just make your own Winogradsky column at home. With a few cups of mud and some other simple materials, you can grow a lush microbial garden. Over time, your column will form layers of different colors, which correspond to different colonies of bacteria.
Tools + Materials
- Buckets
- Shovel
- Large mixing bowl
- Mixing spoon
- 1⁄4-page of shredded newspaper
- 1 egg yolk
- Scissors
- 1 two-liter soda bottle with top cut off
- Plastic wrap
- Rubber bands
Instructions
- Collect half a gallon of mud from a pond or stream, adding water until it has the consistency of a milkshake.
- Mix a quarter of the mud with egg yolk and shredded newspaper. Spoon the mixture into the bottle. Keep filling the bottle with mud, and tap it periodically to remove air pockets.
- Add an inch of pond water, leaving a little air at the top. Seal the bottle with plastic wrap and rubber bands, and place it near a window, out of direct sunlight.
- Layers will develop over two months. Look for dark green, purple, and black sulfur-eating bacteria at the bottom; red, orange, brown, and purple carbon-eating ones in the middle; and green photosynthesizing microbes at the top.
This article was originally published in the March/April 2016 issue of Popular Science, under the title “Grow a Thriving Bacterial Zoo.”
