A catchment after rain

After rain falls on a forested hillside, some water runs into a stream and then the sea. Some soaks into soil and rock. Sunlight warms water at the surface, causing evaporation. Plants take up water through their roots and release water vapour from their leaves. In the same forest, plants take in carbon dioxide from the air during photosynthesis. Carbon becomes part of plant material. Animals eat plants, and respiration returns some carbon dioxide to the air. When organisms die, decomposers break them down; some carbon enters the soil.