In a Winogradsky column the conditions change from oxygen-rich (aerobic) at the top of the column to oxygen-deficient (anaerobic) at the bottom. Different microorganisms develop in the various environmental niches throughout the column. The products of one microbe's metabolic activities support the growth of another microbe. The result is that the column becomes a self-supporting ecosystem, which is driven only by the energy received from the incoming sunlight. Winogradsky columns are easily constructed, and are often used in classroom experiments and demonstrations.

The Winogradsky column is named after Sergius Winogradsky, a Russian microbiologist who was one of the pioneers of the study of the diversity of the metabolic activities of microorganisms.

To set up a Winogradsky column, a glass or clear plastic tube is filled one-third full with a mixture of mud obtained from a river bottom, cellulose, sodium sulphate, and calcium carbonate. The remaining two-thirds...