UCA_C3-C4_day44

A few weeks after the preparation of the column, we observed both of them, and we noticed some changes.

The C3 group’s column presents the following characteristics:

• The orange spots are photoheterotrophic microorganisms, which use as power source the solar energy, and reduced iron.
• At the surface, we could find green algae and cyanobacteria, since they need oxygen to perform the cellular respiration and sunlight to make the photosynthesis.
• Along the column, we could find tiny white spots, which can be elementary sulfate.
• We could also see small bubbles, which can be due to the fermentation of the chemoheterotrophic micoorganisms.
• We can appreaciate along the column some black spots, which are more intense at the bottom of it. They are due to the anaerobic microorganisms, being stronger as the oxygen gradient decreases.

The C4 group’s column differs from the C3’s in the following characteristics. The rest of the microorganisms are the same as the other one.

• We can find along the coloumn oxidizing bacteria.
• The photoheterotrophic microorganisms of the column use as carbon source the cellulose of paper, and as power source the sunlight.
• It doesn’t present white spots since it didn’t contain sulfate.
• The orange spots are bigger, because of the cellulose that the paper provided.