Ramping up physical activity quite dramatically and in a departure from scheduled proceedings, the afternoon was spent constructing Winogradsky Columns, curious devices created to construct cultures of multiple microorganisms. The contraption mixes sand and mud with sources of carbon and sulfur. After several months of incubation in sunlight, it provides a gradient of aerobic-anaerobic activity. Finnish winter might widen the incubation time though.
To assemble the columns, it was necessary to source the base components from the grounds nearby. One group fetched mud from the shoreline, and another from a nearby pond on the Aalto University campus. The columns will hopefully be the first of many hermetically sealed ecosystems constructed during this workshop.
See photos and practical guide below.
Practical guide:
Materials
- Tall glass or plastic tube (roughly 5 x 30 cm)
- Calcium carbonate
- Calcium sulfate or sodium sulfate (e.g. ground eggshell or egg yolk, raw or hard boiled)
- Cellulose (e.g. shredded newspaper or hay)
- Mud from bottom of pond (or alternative water source such as river, lake)
- Water from pond (or alternative)
- Optional: Sand
- Possible tools: gloves, digging tool, buckets, boots, bowl for mixing
Instructions
Note: this experiment does not require exact measurements
- Remove any sticks, stones, leaves or other debris from the mud
- To supplement the mud, add some sulfate, for sulfur, and cellulose, for carbon
- Fill lower one-third of the tube with supplemented mud, removing any air bubbles
- Choose from the options below:
- Option 1: fill tube to two-thirds with unsupplemented mud, then fill to top with pond water
- Option 2: fill tube to two-thirds with sand*, then fill to top with pond water
- Option 3: fill the rest of the tube with water from pond
- Leave some air space at the top of the tube
- Cap or seal the tube tightly, to prevent evaporation
- Place in strong natural light source, such as near a window or under a light (or both), for several months, at least 2-3
- Microorganisms will appear in separate zones of the tube, according to the suitability of each environment for certain processes
- Find out about the different processes and activities taking place in a model column, such as fermentation and anaerobic respiration: http://archive.bio.ed.ac.uk/jdeacon/microbes/winograd.htm
*sand makes later observation and sampling of cultures easier