The Hydrosphere

Students will be able to: • The Hydrosphere • Describe Earth’s hydrosphere as one of the major subsystems of the Earth. Explain how hydrosphere’s interaction with other subsystems results in the changes of Earth’s surface. The Hydrosphere Key Vocabulary: • Abiotic • Atmosphere • Biosphere • Biotic • Deposition • Erosion • Geoscience Processes • Hydrosphere • Lithosphere • Water Cycle • Weathering The Earth’s System The Hydrosphere The term “Earth system" refers to Earth´s interacting physical, chemical, and biological processes. Earth’s system consists of the land, oceans, air, and poles. It includes the planet's natural cycles — the carbon, water, nitrogen, phosphorus, sulfur and other cycles — and deep Earth processes. The Hydrosphere The Earth system is a collection of interdependent parts enclosed within a defined boundary. These interdependent parts are called “spheres“ namely • lithosphere • hydrosphere • biosphere • atmosphere. The Hydrosphere Earth’s spheres affect global change. Global change refers to planetary-scale changes in the Earth system. The term also includes planetary scale changes to atmospheric circulation, ocean circulation, climate, the carbon cycle, the nitrogen cycle, the water cycle and more. The Hydrosphere The Four Spheres of the Earth Atmosphere • It is the protective blanket of air that surrounds the Earth. • It is the product of 4.6 billion years of evolution, shaped by everything from its proximity to the Sun to the rise of photosynthetic life. The Hydrosphere The Four Spheres of the Earth Biosphere • It is the biotic part of Earth and includes all living organisms and organic matter that has not decomposed. • This sphere extends from the deepest root systems of trees to the dark environment of ocean trenches, to lush rain forests and high mountaintops. The Hydrosphere The Four Spheres of the Earth Lithosphere • It is the solid Earth that includes the continental and ocean crust as well as various layers of Earth’s interior. • The surface of this sphere is always changing. • It is also known as the geosphere. The Hydrosphere The Four Spheres of the Earth Hydrosphere • It consists of the Earth’s water resources such as oceans, lakes, rivers, streams, groundwater, and glaciers. • 97.5% of water on Earth is saltwater. Only 2.5% is freshwater! All the water we have on earth is the water we started with. Decide which of Earth’s spheres matches the descriptors below. 1. This sphere contains all the water found on our planet. 2. This sphere protects us from harmful UV rays and radiation. Earth System Comprehension Check 3. This sphere is also known as the “geosphere“. 4. This sphere contains all living organisms, including humans. Decide which of Earth’s spheres matches the descriptors below. Answers 1. This sphere contains all the water found on our planet. lithosphere 2. This sphere protects us from harmful UV rays and radiation. atmosphere Earth System Comprehension Check 3. This sphere is also known as the “geosphere“. lithosphere 4. This sphere contains all living organisms, including humans. biosphere The Earth’s Hydrosphere The Pacific Ocean, part of Earth's hydrosphere The Hydrosphere This sphere is a key component of Earth’s interdependent physical systems. The hydrosphere is the sum of Earth’s water, in the ocean, the ground, on the surface, and in the air. It is divided into saltwater and freshwater. The Hydrosphere About 71% of the Earth’s surface is water-covered, and the oceans hold about 96.5% of all Earth’s water. Water also exists in the air as water vapor, in rivers and lakes, in icecaps and glaciers, in the ground as soil moisture and in aquifers, and even in living things. Distribution of Earth’s Water The Hydrosphere This bar chart shows how almost all of Earth’s water is saline and is found in the oceans. Of the small amount that is actually freshwater, only a relatively small portion is available to sustain human plant, and animal life. Distribution of Earth’s Water The Hydrosphere In the first bar, notice how only 2.5% of Earth’s water is freshwater. This is the amount needed for life to survive. The middle bar shows the breakdown of freshwater. Almost all is locked up in ice and in the ground. Only a little more than 1.2% of all freshwater is surface water, which serves most of life’s needs. Distribution of Earth’s Water The Hydrosphere The right bar shows the breakdown of surface freshwater. Most of this water is locked up in ice, and another 20.9% is found in lakes. Rivers makes up 0.49% of surface freshwater. Although rivers account for only a small amount of freshwater, this is where humans get a large portion of their water from. Distribution of Earth’s Water The Hydrosphere Since Earth is a closed system, water continuously move through it as the sun’s radiation causes it to evaporate, rise into the atmosphere, condense, then fall as precipitation to be used or recycled. This process is called the water cycle, which you will learn more about in the next lesson. Decide if the following statements are true or false. The Hydrosphere Comprehension Check 1. The hydrosphere is the sum of all of Earth’s water. 2. Approximately 71% of Earth’s surface is covered in water. 3. Over 97% of the Earth is composed of salt water. 4. A large portion of Earth’s water is freshwater. 5. Water in a liquid state is known as water vapor. Decide if the following statements are true or false. Answers The Hydrosphere Comprehension Check 1. The hydrosphere is the sum of all of Earth’s water. True 2. Approximately 71% of Earth’s surface is covered in water. True 3. Over 97% of the Earth is composed of salt water. True 4. A large portion of Earth’s water is freshwater. False 5. Water in a liquid state is known as water vapor. False Hydrosphere’s Interaction with Other Earth’s Spheres The Hydrosphere How Water Changes Earth’s Surface? Geoscience processes such as weathering, erosion, and deposition, are processes that are constantly changing the Earth’s surface. One of the factors that cause these processes to take place is the continuous movement and interaction of water with other spheres of the Earth. The Hydrosphere How Water Changes Earth’s Surface? At the ocean shore, the pounding of the waves breaks down rock. It grinds rock into tiny grains of sand. Running water from falls and streams also cause rocks to wear away. This is the reason why smooth rocks are found nearby streams or waterfalls. The Hydrosphere How Water Changes Earth’s Surface? In the winter, precipitation (snow or rain) falls onto rock. The sun causes snow to melt. At night when it gets colder, the water freezes. When water freezes, it expands or gets bigger. Water seeps into the cracks of rock. When it freezes, it forces the rock to crack and break apart. The Hydrosphere How Water Changes Earth’s Surface? All these examples show weathering which is the processes of breaking down of rocks. When rocks are broken down into pieces, they are easily transported to another place. The movement of weathered rocks is called erosion. The Hydrosphere How Water Changes Earth’s Surface? The eroded rocks will continue to move by running water and be deposited into another venue and settle there for good. This process is called deposition. Deltas are wetlands that form as rivers empty their water and sediment into another body of water, such as an ocean, lake, or another river. The Hydrosphere How Water Changes Earth’s Surface? Deposition helps in the formation of new rocks. As sediments are continuously carried and deposited into a new area, gravity will act on them until they pile up and eventually be compressed. Over time, sedimentary rocks are formed. The Hydrosphere How Water Changes Earth’s Surface? Water is essential for plants to grow. Plants’ roots are anchored to the soil for stability and growth. When plants’ roots grow bigger, they sometime break out of the ground which also results in weathering of rocks. The Hydrosphere How Water Changes Earth’s Surface? Atmosphere is a mixture of different gases, and some of these gases are harmful which results in pollution. The sun’s heat causes water to evaporate, and this process is the first step for rain formation. When water vapor mixes with harmful gases in the air, acid rain is formed. Acid rain corrodes rocks which can change Earth’s landscape too. Answer the following questions. 1. What are the geological processes that help shape the Earth’s surface? The Hydrosphere 2. How does water trigger different geological processes? Answer the following questions. Answers 1. What are the geological processes that help shape the Earth’s surface? Geoscience processes such as weathering, erosion, and deposition, are processes that are constantly changing the Earth’s surface. The Hydrosphere 2. How does water trigger different geological processes? The continuous movement of water acts as an agent of weathering, erosion, and deposition.