Lab 1 - Winogradsky column

Question 1

Who was Sergei Winogradsky?

Answer 1

• Ukranian microbiologist in 1856-1953
• Discovered lithotrophy and chemoautotrophy

Question 2

What is the importance of the region where water and sediments meet?

Answer 2

Site of many of the major processes that determine the
earth’s environmental conditions

Question 3

Which 2 microbes are restricted to anaerobic conditions in sediments?

Answer 3

Sulphate-reducing bacteria and anaerobic marine photosynthetic bacteria

Question 4

How does the Winogradsky column work?

Answer 4

• Enrichment culture to stimulate aerobic and anaerobic microbes
• Gradients of nutrients, oxygen/anaerobiosis and light
• Interacting microbial populations recycling nutrients reflects globally important process

Question 5

Describe briefly how to make a Winogradsky column

Answer 5

1. Mud
2. CaSO4/Na2SO4 (egg yolk), CaCO3 (eggshell), cellulose (hay/paper)
3. Water and mix to slurry
4. More water and mud layers
5. Cover wih film and incubate in both daylight and incandescent light

Question 6

Explain the responsible microbes behind the following colours
- Black/brown (bottom)
- Green (middle)
- Purple (middle)
- Yellow/orange (top)
- Bright green (top)

Answer 6

• Black/brown = sulfur reducing bacteria
• Green = green sulfur anaerobic bacteria
• Purple = purple sulfur and non-sulfur bacteria (anaerobic photosynthetic)
• Yellow/orange = non-sulfur photosynthetic
• Bright green = photosynthetic cyanobacteria