After weeks of preparation Winogradsky’s column we observed significant changes in the appearance of the column, as we can see in the pictures. These changes are different from the column was exposed to sunlight respect to which was in almost total darkness.
- Column exposed to the sun: In the face of the column that is exposed to direct sunlight we see very little change . The few changes that are occurring at the bottom of the column, where we see an intense black color. This black color is given by the production of hydrogen sulfide (H2S) bacteria that use sulfur as an energy source.
In the face that is not directly exposed to sunlight we appreciate more changes : The zone is much rich black color ; It can be seen pink small areas , due to some purple sulfur bacteria .
orange stripes are appreciated caused by iron oxide
- Column in the darkness: In this column we see that the black color is much more
spread throughout the column the column , and there aren’t any differentiations between two sides , since none has been exposed to the sun.
The orange coloration only appears, in this case in the surface of the column.
- Given these observations we can deduce that the action of light affects the development of microorganisms , favoring those who are photosynthetic , and disadvantaging Sulfur bacteria and other organisms that develop in the bottom of the column.