Sustainability: Water - The Water Cycle

Summary

The water cycle, a vital process for life on Earth, involves water continuously circulating between the atmosphere and the planet's surface. It includes precipitation, runoff, interception by vegetation, infiltration into soil, percolation to aquifers, and discharge into bodies of water. Water returns to the atmosphere through evaporation, transpiration from plants, and respiration. This cycle, though simple in concept, is intricate and essential for sustaining life.

Takeaways

• 💧 All water on Earth is the same ancient water, continuously cycled for millions of years.
• 🌍 The water cycle is essential for life on Earth, maintaining a perfect balance of water flow and storage.
• 🌧️ Water moves through various forms of precipitation, including rain, snow, hail, and fog, cycling between land, rivers, and oceans.
• 🏞️ Water stores exist in the ocean, ice sheets, glaciers, rivers, lakes, plants, soil, and underground aquifers.
• 🌳 Precipitation on land can be intercepted by vegetation or absorbed by the soil, depending on surface conditions.
• 🪨 Groundwater infiltrates deep into the earth, where it can remain for thousands to millions of years before moving toward rivers, lakes, or oceans.
• ☀️ Evaporation occurs when the sun heats water, turning it into vapor, which is then released back into the atmosphere.
• 🌱 Plants contribute to the water cycle through transpiration, releasing water vapor into the atmosphere.
• ☁️ Water vapor cools, condenses into clouds, and eventually falls back to Earth as precipitation in a continuous cycle.
• 🔄 The water cycle involves several key processes like interception, infiltration, percolation, discharge, evaporation, and condensation.

Q & A

What is unique about the water on Earth?

All the water on Earth today is the same water that has always existed, flowing in a continuous cycle for millions of years.

What is the water cycle, and why is it important for life on Earth?

The water cycle is the process by which water moves between different states and locations on Earth. It is crucial for life because it provides a consistent supply of fresh water and regulates the Earth's environment.

How does water move through different stages in the water cycle?

Water moves through stages like precipitation, infiltration, percolation, and evaporation. It can flow as rain, run into rivers, infiltrate soil, or evaporate into the atmosphere to begin the cycle again.

What are some of the primary 'storages' of water in the water cycle?

Primary storages include the oceans, glaciers, ice sheets, snow packs, rivers, lakes, reservoirs, wetlands, soil, plants, and underground aquifers.

What role does precipitation play in the water cycle?

Precipitation is the process where water falls to Earth in various forms like rain, snow, sleet, or hail. It replenishes surface water and contributes to groundwater recharge.

What happens to water that falls on land?

Water that falls on land can either be intercepted by vegetation, run off into rivers, infiltrate the soil, or percolate into groundwater.

What is evapotranspiration, and how does it contribute to the water cycle?

Evapotranspiration is the combination of evaporation from soil and water surfaces and transpiration from plants. It releases water back into the atmosphere, continuing the water cycle.

How does water stored underground move?

Groundwater moves laterally or sideways toward rivers, lakes, or the ocean. Deeper groundwater moves slower and may take thousands to millions of years to discharge.

What causes water to evaporate, and where does this occur?

Water evaporates due to the heat of the sun, turning from liquid into gas. This occurs on all wet surfaces, including lakes, rivers, soil, and even in the atmosphere.

How do clouds form in the water cycle?

Clouds form when water vapor in the air cools and condenses into droplets, often around particles like smoke or dirt. When these droplets grow large and heavy, they fall back to Earth as precipitation.