Winogradsky column day 22

Winogradsky column
day 22

During the last week the rusty layer has become higher and the contrast to the transparent layer beneath has become more accentuated.

Winogradsky column day 15

Winogradsky column
day 15

After two weeks the water has become turbid. The entire sediment layer is now black, probably as a result of the processes mentioned in the previous blog post. Above the sediment one can see a thin red layer. I guess this is formed by anaerobic purple sulfur bacteria that get energy from H₂S. Further upwards is a break followed by a level with a rusty shade. I suppose this layer is made of non-sulfur purple bacteria, that uses H₂ as energy source. This type of bacteria do not tolerate sulfur as well as the sulfur bacteria, what should explain the gap between the layers, since the concentration of sulfur declines toward the top. At the water surface at the top of the column some lighter particles float.

Rhodopseudomonas palustris, the bacteria I want to isolate is a purple non-sulfur bacteria. Probably it's already possible to do that, even though I'd like to wait one or two more weeks till I try something new.

References

• Winogradsky column: perpetual life in a tube — Edinburgh University