Oxygen Release and Carbon Input During Photosynthesis

When plants perform photosynthesis, they use carbon dioxide ($CO_2$) from the air and water ($H_2O$) from their roots. With energy from sunlight, these molecules are transformed into sugars (plant matter) and oxygen gas ($O_2$).

The oxygen can be seen as bubbles forming on the surface of aquatic plants, like Elodea. This visible evidence shows that plants are changing air and water into new materials during growth.

Researchers from the Smithsonian Environmental Research Center measured oxygen production and carbon uptake by aquatic plants under different light levels.

Table 1.

As light intensity increases, plants release more oxygen and absorb more carbon dioxide. This shows that plants are using $CO_2$ from the air and $H_2O$ from their environment to produce sugars that make up their mass - the materials for growth. The released oxygen is evidence that new matter is being formed through chemical change.

This experiment directly demonstrates how air and water are transformed into plant tissue and oxygen gas through photosynthesis.

Graph of Information - Figure 1.

Graph of Information - Figure 2.