Few weeks later, it is noted a remarkable development
and great evolution of the Winogradsky column.
First of all, at the dark side of the bottle, the bottom
had been dispersed upwards; the orange lines we saw two weeks ago, now
extended, occupying the entire area of the bottle.
Furthermore, there was a clear difference between the
part of the column that received light and the one that did not.
The area did not received light was coloured black; we
came to this conclusion with the help and the analysis of the bottle in
complete dark conditions.
Besides this, at the top of the column could be seen
filaments that were born from the sediment, spreading in the water.
Analysing the column and researching on the Internet,
we could say that the light side is rich in O2 as we climb because of
aerobic bacteria who usually develop in little lakes. They could be algae or photosynthetic
cyanobacteria.
The column become anaerobic as far as we descend,
being completely anaerobic at the bottom. In this way, we can find sulphate-oxidizers
(Beggiatoa or Thiobacillus), purple
non-sulphur bacteria (Rhodospirillum and Rhodopseudomonas)
who produce these orange lines, purple sulphur bacteria (Chromatium), green sulphate bacteria (Chlorobium) with a green colour, sulphate-reducers (Desulfovibrio) who use by-products other
bacteria to produce large amounts of SH2 and finally, we can find
cellulose fermenters.
We could conclude that the amount of sulphur descended
downwards at the dark side.
Sounds great. Did you observe all these types of bacteria in your columns? I can only see black spots and rusty patches.
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