Introduction
Earth is known as the " Blue planet " due to abundant water present in it. Oceans are the storehouse of water. There is approximately 320,000,000 litres of water present in the Ocean. But from where does all this water come from?
It is the result of the continuous water cycle which provides water to earth and to oceans. Over a short period of time the amount of water in the ocean doesn't change but in a longer span it does have an impact. Let's have a look at the water cycle which keeps on circulating huge amounts of water from the ocean and then gives back to oceans.
The Water Cycle
Evaporation, cooling, freezing condensation, melting are all important processes that drive the hydrological cycle which is a never-ending process of water circulation from oceans to clouds and rivers and back to oceans. The steps involved in cycling of huge amount of water are -
Evaporation - The sun which is the primary source of energy heats up the large surface area of oceans and causes the water from oceans to evaporate. This large amount of water constitutes the atmospheric water vapour. Warm water vapour rises up thereby cooling the surface of water. Huge amount of heat is absorbed by the ocean for the heating up of water from the surface of Ocean continuously.
Condensation - the water vapour rises up continuously and is carried away by the atmospheric air currents where it cools and condenses to form the clouds. Condensing water vapour releases latent heat and this latent heat plays an important role in Earth's heat balance.The clouds are accumulation of fine droplets of water at extremely low temperature and remain suspended at high altitudes.
Precipitation - the clouds collide and their the electrical discharge which results in the precipitation of water droplets to the ground. The precipitation may be in the form of rain, snow, hail etc. Most precipitation falls on water bodies or on land.
Surface runoff - The water that falls on land meets a different fate. A portion of water flows over the ground as runoff and due to gravity it eventually is discharged into rivers and other water bodies.
Stream flow - The water accumulated from surface runoff and drainage flows into streams, lakes and rivers which travel along the surface of earth to reach sea and finally meet the oceans.
Soil moisture - Some water infiltrates into the soil which is utilised by plants and returns to the atmosphere by evapotranspiration.
Groundwater - Deep infiltration of water results in replenishing ground water table which then later emerges as springs or is taken by humans for their use.
Over time all this water keeps circulating through various channels, but ultimately it is poured back to the oceans from where it's journey started.
Significance of Water Cycle
1.The cycling of water is related to energy exchange between ocean, atmosphere and land.
2.It influences Earth's climatic conditions and climate change to a great extent.
3. Large amounts of heat absorbed by the ocean helps in buffering the green house effect from increasing carbon dioxide and other gases.
4.Condensed water vapour releases latent heat which drives atmospheric circulation in the tropical regions.
FAQs on Back to Oceans
1. What is the water cycle and why is it often related to the phrase 'Back to Oceans'?
The water cycle describes the continuous movement of water on, above, and below the Earth's surface. It's often called 'Back to Oceans' because the oceans are the planet's largest water reservoirs. Most water that evaporates into the atmosphere eventually finds its way back to the oceans through rain and river flow, completing the cycle.
2. What are the main stages of the water cycle explained simply?
The water cycle has four primary stages that work in a continuous loop:
- Evaporation: The sun's heat turns water from oceans, lakes, and rivers into gas (water vapour), which rises into the air.
- Condensation: As the water vapour rises and cools, it turns back into tiny liquid water droplets, forming clouds.
- Precipitation: When these droplets in the clouds become too heavy, they fall back to Earth as rain, snow, or hail.
- Collection: The water that falls to Earth collects in rivers, lakes, and oceans, or soaks into the ground, ready to start the cycle again.
3. What is the difference between evaporation and transpiration in the water cycle?
Both processes turn liquid water into water vapour, but they happen in different ways. Evaporation is the process of water turning to vapour from open water bodies like oceans and lakes. Transpiration is the process where plants absorb water through their roots and then release it as vapour from their leaves.
4. How do clouds form and what makes them release rain?
Clouds form through a process called condensation. When warm, moist air rises, it cools, causing the invisible water vapour to change into tiny, visible water droplets or ice crystals. These droplets gather around dust particles in the air to form a cloud. When enough of these droplets join together and become too heavy to stay afloat, gravity pulls them down as precipitation, such as rain.
5. Why is the sun so important for the water cycle to work?
The sun is the main engine that drives the entire water cycle. It provides the heat energy necessary for evaporation, the very first step. Without the sun's warmth, water from oceans and other bodies of water would not be able to turn into vapour and rise into the atmosphere to form clouds.
6. If ocean water is salty, why is rain fresh water?
This is one of the most important functions of the water cycle. When the sun heats ocean water during evaporation, only the pure water turns into vapour. The salt and other minerals are too heavy and get left behind in the ocean. Therefore, the water that forms clouds and falls as rain is naturally fresh and clean.
7. How do plants help return water to the atmosphere?
Plants play a vital role in the water cycle through a process called transpiration. They draw water up from the ground through their roots and move it to their leaves. The leaves then release this water into the air as water vapour. This process is a major contributor of moisture to the atmosphere, helping to form clouds.
8. What is an aquifer and why is it important for us?
An aquifer is a large, underground layer of rock or soil that holds water, known as groundwater. This water comes from rain that soaks into the ground. Aquifers are incredibly important because they act as natural storage tanks for fresh water, which we can access by drilling wells for drinking, farming, and other needs.
9. What is the difference between a sea breeze and a land breeze?
The difference lies in the direction of wind flow, caused by how quickly land and sea heat up. A sea breeze occurs during the day when the land is warmer than the ocean, so cool air blows from the sea to the land. A land breeze occurs at night when the land cools down faster than the ocean, so cool air blows from the land out to the sea.
