Aska
Ioanna - Giannakos Kostas
Hello everyone!!
We
are a team of two people and we have an experiment about the Winogradsky
column. The Winogradsky column is a simple device for culturing a large
diversity of microorganisms. The device is a column of sea sediment and water
mixed with a carbon source such as newspaper (containing cellulose), egg-shells
(containing calcium carbonate), and a sulfur source such as egg yolk. The column is a plastic bottle that is filled with two
third full of a rough mixture of ingredients and one third full of sea water. The place that we put our bottle , was
interior. Incubation took place in sunlight for 7 weeks. The ingredients of our
experiment were taken from Anauros beach which is located in the southewest of
Volos. Let’s see the progress of our
experiment.
1st
day
During
the first day of our experiment, the column was sealed and
placed in a bright place
with small temperature changes.
Image 1
After 2 weeks
Here we
noticed an increase in the turbidity of
water. Because of oxygen's low solubility in water, the water quickly
becomes anoxic so we observed the creation of a black banding around
the bottle. The black color
is caused by the presence of FeS (silica-mineral), which is formed anaerobically from the iron
and sulfur reactions, as there is
production of hydrogen sulfide.
Image
2
After 4 weeks
Here,
the black color increased in our experiment and the turbidity of water increased too. Anaerobic bacteria are still present to a large extent
in the sediment, and there is still capacity for biofilm creation and colony
expansion.
Image
3
After 6 weeks
After
6 weeks we observed that the bottle of our experiment became totally black at all levels and the turbidity reduced
in addition with the previous
observation.
Image
4
While
the Winogradsky column is an excellent tool to see whole communities of
bacteria, it does not allow one to see the densities or individual bacterial
colonies. However its importance in environmental microbiology should not be
overlooked and it is still an excellent tool to determine the major bacterial
communities in a sample.
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