Water cycle is the continuous movement of water on, above and below the Earth's surface.
Plants also release water vapour into the atmosphere through their leaves by the process called transpiration.
As water vapour rises into the atmosphere, it cools and condenses into tiny droplets, forming clouds.
When water droplets in clouds combine and become heavy, they fall to the ground as rain, snow, sleet or hail.
Water that infiltrates the groundwater can be stored in underground reservoirs known as aquifers
.Water that does not infiltrate the ground flows over the surface of the Earth as run-off. This water eventually returns to rivers, lakes and oceans completing the cycle. The cycle starts again.
1. Regulation of Climate and Temperature • Moderates Global Temperature: The water cycle regulates Earth's temperature by redistributing heat. Evaporation absorbs heat from the environment, cooling the surface, while condensation releases heat into the atmosphere, warming it. • Cloud Formation and Weather Patterns: The water cycle is responsible for cloud formation, which influences weather patterns and precipitation, helping to regulate local and global climates. ________________________________________ 2. Purification of Water • Natural Filtration System: As water moves through the cycle, it undergoes natural purification. Evaporation leaves behind impurities, ensuring that water vapor entering the atmosphere is clean. When water infiltrates the ground, it is further filtered through soil and rock layers. • Sustainable Freshwater Supply: Through precipitation, the water cycle replenishes freshwater sources like rivers, lakes, and aquifers, which are essential for drinking water, agriculture, and sanitation. ________________________________________ 3. Support for Ecosystems • Sustains Plant and Animal Life: The water cycle provides the water necessary for plant growth through precipitation and soil moisture. Plants, in turn, form the basis of food chains, supporting both herbivores and carnivores. • Maintains Aquatic Habitats: Oceans, lakes, rivers, and wetlands are replenished through rainfall and runoff, supporting diverse ecosystems and aquatic life. ________________________________________ 4. Soil and Land Formation • Erosion and Sedimentation: Water cycle processes like rainfall and runoff help shape the Earth’s surface by causing erosion and transporting sediments. These processes contribute to the formation of valleys, deltas, and other landforms. • Fertilization of Soil: Rainfall helps distribute nutrients in the soil, supporting the growth of vegetation and maintaining soil fertility. ________________________________________ 5. Agriculture and Food Production • Irrigation and Crop Growth: Precipitation provides water for agriculture, which is vital for growing crops and sustaining livestock. Without the water cycle, there would be no natural source of water for cultivating food. • Groundwater Replenishment: The infiltration of water into the ground helps maintain groundwater levels, which are crucial for irrigation in regions that rely on wells and aquifers. ________________________________________ 6. Balancing Water Distribution • Movement Between Ecosystems: The water cycle ensures that water is distributed across different ecosystems, from oceans and lakes to forests and deserts. This movement of water supports biodiversity by providing the necessary resources for life in various environments. • Prevents Water Stagnation: By continuously moving water through the atmosphere, land, and oceans, the water cycle prevents water from becoming stagnant, which can lead to the accumulation of pollutants and harmful organisms. ________________________________________ 7. Global Water Availability • Maintains Ocean and Freshwater Levels: The cycle helps balance water levels in oceans, rivers, lakes, and groundwater reserves, ensuring that water is available for humans, animals, and plants. • Replenishes Depleted Sources: The water cycle naturally replenishes water bodies that may have been depleted by droughts, human consumption, or industrial use. ________________________________________ 8. Support for Human Activities • Industrial and Domestic Use: The water cycle provides a continuous supply of water for human needs, including drinking, cooking, cleaning, sanitation, and various industrial processes. • Disaster Prevention: By redistributing water globally, the water cycle can help mitigate the severity of droughts and floods, although extreme weather events can still occur.