Winogradsky Column

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The Winogradsky Column got its name from the well-known microbiologist Sergei Nikolayevich Winogradsky. He developed the column in order to be able to study the diversity of soil bacteria more closely. A glass cylinder is used as a column, which is partly filled with pond sludge mixed with eggs, gypsum and newspaper which serve as nitrogen, sulphur and carbon sources. After that one has to make sure that the cylinder receives enough sunlight. Over time, differently colored zones develop in the column, from the top to the bottom an oxygen gradient develops, and from the bottom to the top a sulfur gradient is created. Strictly anaerobic soil bacteria form the bottom of the column. Phototrophic green sulfur bacteria and sulfur-reducing bacteria live above them. Among other substances, this region is rich in sulphide and poor in oxygen. Many of these bacteria can be seen as green spots on the inside of the column. The layer above is home to many phototrophic purple sulfur bacteria. Their photosynthesis works with another electron donor, and instead of green, they are purple. The zone above is inhabited by non-sulfur purple bacteria, this part of the column is aerobic and contains very little sulfur. The bacteria in this zone perform photosynthesis with sulfur-free compounds. On top of this zone there is a layer of water and a layer of air with cyanobacteria and algae. These organisms carry out oxygen photosynthesis and ensure that this top zone stays aerobic.

 

Explanation for children:

The microbiologist Sergei Nikolayevich Winogradsky invented the Winogradsky Column. This is a glass column filled with pond sludge and mixed with some eggs and newspaper. This column is the perfect habitat for many bacteria. Over a long period of time and with plenty of sunlight, clearly distinguishable layers develop in the column. Each layer is home to different bacteria. There is an anaerobic zone, a sulphur zone, a water zone and an air zone. In research, Winogradsky columns are mainly used to study the sulfur cycle in soil and other microbial metabolic pathways.