Hi, everyone! I know I should post more often, but
the column did not change much...
- Week 2, 17th March:
The number of black dots has
increased, as I said in the previous post, I think that they are
colonies of desulfovibrio
bacteria, the foul odour of the bottle has increased.
- Week 3, 24th March:
The number of black dots has
increased(again). There are more desulfovibrio bacteria.
The water used to be orange, but now it
is pale brown.
There aren't black dots near the water,
that zone (the less anaerobic zone) is brown.
- Week 4, 31st March:
The black colour, which according
to our hypothesis are the colonies of desulfovibrio bacteria,
prevails in the bottle, but the mud near the water is brown. It is
explained by the existence of the oxygen and the sulfur gradient, the
desulfovibro bacteria are in the anaerobic zone, where the hydrogen
sulfide concentration is higher.
The microaerophilic zone,the interface of
sulfide-containing mud and the more aerobic pond water, is brown, we
think that bacteria that can oxidise sulfur are growing there, they
oxidise it to obtain energy and that energy is used to produce
organic molecules.
Under the previous zone, the mud is orange, the
presence of iron oxidising bacteria can produce this colouration.
There are some bivalves in the brown mud.
The water, the aerobic zone, is not transparent,
photosynthetic bacteria(cyanobacteria) and algae may be growing
there. They use light energy and CO2 to produce organic molecules and oxygen, maintaining the O2 gradient.
- Week 5, 7th April:
The water colour has
changed, it is brown, the surface is not transparent, this change
might have been produced by the increasing number of cyanobacteria.
The microaerophilic's
zone colour is pale brown, the less anaerobic zone colour is brown
(rust colour), and orange.
Nonsulfur photosynthetic
bacteria grow in the rust coloured zone, they produce organic molecules when they fix CO2 , they use organic acids or ethanol as electron donors rather than sulfide.
Nice!!!
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