WINOGRADSKY COLUMN (6th week)
Rio San Pedro sediment + 0,3 g NaCl + 0,3 K3PO4 + 0,4 g sugar + 0,4 g CaSO4
In this image, you can see the different areas of each column after about six weeks of its completion.
Several weeks after the Winogradsky column was made, many appreciable changes were observed in each column.
In this image, you can see the different areas of each column after about six weeks of its completion.
In the column on the left, which was exposed to sunlight, there are four areas where different microorganisms have intervened, whereas in the right column, which was devoid of light, has three distinct areas. These changes are due to the action of different bacteria in each area of the column.
Column exposed to light.
This column is characterized by the presence of light, so the bacteria are photosynthetic.
The lower zone is characterized by being anaerobic and fermenting, but without oxygen. This fermentation transforms the organic matter into sulfur as a gas (H2S normally). This gas decreases as we move through the column to higher areas. In this zone, the bacteria transform the sulfur present in CaSO2 and transform it into H2S. This area usually presents a black color and occupies much of the column.
As we rise in the column, the hydrogen sulphide from the bottom is consumed by anaerobic bacteria that reduces the present sulfur. This area has a black color and also occupies a large area of the column.
The brown area has the presence of sulfur and oxygen. This zone is aerobic because diverse bacteria oxidize the sulfur coming from inferior zones. Sulphates appear in this zone.
At the top of the column is the aerobic zone, where there is a higher concentration of oxygen. For this reason, bacteria that inhabits aquatic environments appear. This area is rich in organic matter and is the smallest area of the column.
Column not exposed to light.
This column presents bacteria that do not use sunlight for their evolution, that is, they are chemosynthetic. In the areas of the column there are many similarities to those mentioned above in the previous column.
The lower zone is also similar, where the organic matter is transformed by the bacteria into sulfur, obtaining a great amount of that element.
Next is the largest area of this column, coloured black, where bacteria that uses all the sulfur from the bottom appears. Consequently, there is no intermediate zone in which the sulfur is oxygenated. This area is anaerobic.
The top is aerobic and it is where bacteria transform oxygen. This area is very small compared to the other two.
Moving forward in time, more changes will be seen in the column, as well as bacteria continuing to grow.
In your light exposed column you have some pink and white spots at the bottom. What are these?
ReplyDeleteWhy is the brown layer larger in the ligth column compared to the column kept in the dark?
One correction. Sulfur and sulfides (and sulfites for enologists...) are more reduced forms of S than sulfate