Last October, we attended a huge science expo near home. At one tent, we saw something pretty cool: a microbe biosphere (self-contained ecosystem) in a jar. Most remarkably, the biosphere (known technically as a Winogradsky column) was 12 years old!
The scientist there said we could make our own, using items we had at home: a lidded jar, dirt, water, newspaper, cooked egg yolks (or plaster of paris) and chalk (or egg shells).
Inside the jar were colorful layers of green, orange, black, purple, magenta, and white: all different kinds of microbes. Microbes are living creatures so small you can't see them without a microscope, but if enough of them grow together, you can see their 'community.'
No one knows exactly how many types of microbes exist; some think there might be 1 billion species. Microbes live everywhere--from extreme heat to extreme cold--in water, dirt, on rocks, inside plant roots, and even inside of us. In fact, each of us is home to millions of microbes.
Microbes can make us sick (and then we call them germs) but more often, they help us out. Microbes break down dead plants and turn them into compost. Microbes in our intestines break down food and even make certain vitamins. We also use microbes to make yummy foods--yogurt, of course, but also bread (with the microbe, yeast), cheese, vinegar and pickles, soy sauce, miso, kimchi, kefir and quark, sausage, kombucha, sauerkraut, and even tabasco sauce.
We thought it would be fun to do this as a "make-along" project with other TMG readers. This week, gather your materials; we won't put them together until next week. Then, each Thursday, check in to see our progress. If you want to join us, feel free to leave a comment or post photos of your own project on the TMG flickr pool. I'll include some of those photos in the next post.
What You'll Need For A Homemade Microbe Biosphere
* a large clean glass jar, 1 quart (or 1 liter) sized or larger, with a tight-fitting lid
* a 2 gallon bucket
* a stirring utensil
* a funnel
* optional: tin foil and rubber bands (not needed for a couple of weeks)
For all of these items, choose vessels that later can be sanitized with boiling water or recycled. We're using a 5-quart Ball-type jar with a rubber gasket (be ready to throw the gasket away at the end).
You can also use a 2 liter soda bottle (1 liter is about 1 quart)--cut off the top (to use as a funnel for this project). You'll also need some plastic wrap and rubber bands for your "lid."
For stirring, you could use a long stainless steel spoon or a wooden paint stirrer to throw away.
You can make a funnel using the top of a 2 liter plastic soda bottle if you'd like.
Then, you'll need:
* 1/2 sheet (1 page) of shredded newspaper per 1 quart / liter jar
1 sheet of newspaper = 2 pages of a standard-sized newspaper, about 28" x 24"
Or, use 8 1/2" x 11" paper (outside the U.S., A4); 3 sheets = 1/2 sheet of newspaper
For our 5 quart jar, we need 2 1/2 sheets of shredded newspaper.
1 sheet = 2 pages of newspaper
* 1 1/2 tsp blackboard chalk OR egg shells per 1 quart / liter of jar
1/2 piece of chalk = 1 tsp ground chalk
1 egg shell = 1 tsp ground shell (or more)
Last, around the day before you plan to put it all together, you'll need:
* enough soil or mud to fill your jar 2/3 full
Collect dirt from one source: your garden, or a stream, pond, or forest. Use a container other than your jar. Take out rocks, sticks, or leaves from the dirt. If the ground is frozen, use potting soil.
For a 1 quart / liter jar you'd use about 2 1/2 cups of dirt.
For our 5 quart jar, we need a little over 2 1/2 quarts of dirt.
* an amount of water equal (in cups) to the amount of soil you're using.
If you collected soil from a water source such as a pond or stream, use water from the same source (in a separate container). If you're using dirt from your garden, you can use tap water.
* hard-boiled egg yolk(s) OR plaster of paris
You'll need 1/2 tsp hard-cooked egg yolk or plaster of paris per 1 quart / liter jar.
Generally, there's 2 tsp or more of hard-cooked yolk in one egg.
Plaster of paris is cheap (sold at hobby shops), but see if someone can share theirs with you.
For our 5 quart jar, we used 2 hard-cooked egg yolks.
* a well-lit place to store your biosphere out of direct sunlight or lamplight
You'll need to keep the jar at room temperature and away from the direct sun. Indoor lights are okay, just don't shine lamps on the jar, and don't let the jar get too warm.
Note for the ambitious: You can turn this into an experiment by using more than one jar and then collecting your soil + water from several sources. Or, you can use several jars and one source for soil + water and then store the jars in varying amounts of sunlight (full to complete darkness) to see the different effects. Be sure and label your soil and water containers accordingly. I'll talk about this more next week.
Hope you can join us! Have fun collecting all your 'ingredients' and we'll see you next Thursday when we put them all together.