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The biosphere is made up of the parts of Earth where life exists. The biosphere extends from the deepest root systems of trees to the dark environment of ocean trenches, to lush rain forests and high mountaintops.

Subjects

Earth Science, Geography, Physical Geography

The biosphere is made up of the parts of Earth where life exists. The biosphere extends from the deepest root systems of trees, to the dark environment of ocean trenches, to lush rainforests and high mountaintops.

Scientists describe Earth in terms of spheres. The solid surface layer of Earth is the lithosphere. The atmosphere is the layer of air that stretches above the lithosphere. The Earth's water-on the surface, in the ground, and in the air-makes up the hydrosphere.

Since life exists on the ground, in the air, and in the water, the biosphere overlaps all these spheres. Although the biosphere measures about 20 kilometers (12 miles) from top to bottom, almost all life exists between about 500 meters (1,640 feet) below the ocean's surface to about six kilometers (3.75 miles) above sea level.

Origin of the Biosphere

The biosphere has existed for about 3.5 billion years. The biosphere's earliest life-forms, called prokaryotes, survived without oxygen. Ancient prokaryotes included single-celled organisms such as bacteria and archaea.

Some prokaryotes developed a unique chemical process. They were able to use sunlight to make simple sugars and oxygen out of water and carbon dioxide, a process called photosynthesis. These photosynthetic organisms were so plentiful that they changed the biosphere. Over a long period of time, the atmosphere developed a mix of oxygen and other gases that could sustain new forms of life.

The addition of oxygen to the biosphere allowed more complex life-forms to evolve. Millions of different plants and other photosynthetic species developed. Animals, which consume plants (and other animals) evolved. Bacteria and other organisms evolved to decompose, or break down, dead animals and plants.

The biosphere benefits from this food web. The remains of dead plants and animals release nutrients into the soil and ocean. These nutrients are reabsorbed by growing plants. This exchange of food and energy makes the biosphere a self-supporting and self-regulating system.

The biosphere is sometimes thought of as one large ecosystem-a complex community of living and nonliving things functioning as a single unit. More often, however, the biosphere is described as having many ecosystems.

Biosphere Reserves

People play an important part in maintaining the flow of energy in the biosphere. Sometimes, however, people disrupt the flow. For example, in the atmosphere, oxygen levels decrease and carbon dioxide levels increase when people clear forests or burn fossil fuels such as coal and oil. Oil spills and industrial wastes threaten life in the hydrosphere. The future of the biosphere will depend on how people interact with other living things within the zone of life.

In the early 1970s, the United Nations established a project called Man and the Biosphere Programme (MAB), which promotes sustainable development. A network of biosphere reserves exists to establish a working, balanced relationship between people and the natural world.

Currently, there are 563 biosphere reserves all over the world. The first biosphere reserve was established in Yangambi, Democratic Republic of Congo. Yangambi, in the fertile Congo River Basin, has 32,000 species of trees and such endemic species as forest elephants ( Loxodonta cyclotis) and red river hogs ( Potamochoerus porcus). The biosphere reserve at Yangambi supports activities such as sustainable agriculture, hunting, and mining.

One of the newest biosphere reserves is in Yayu, Ethiopia. The area is developed for agriculture. Crops such as honey, timber, and fruit are regularly cultivated. However, Yayu's most profitable and valuable resource is an indigenous species of plant, Coffea arabica. This shrub is the source of coffee. Yayu has the largest source of wild Coffea arabica in the world.

Fast Fact

Biosphere 2
In 1991, a team of eight scientists moved into a huge, self-contained research facility called Biosphere 2 in Oracle, Arizona. Inside an enormous, greenhouse-like structure, Biosphere 2 created five distinct biomes and a working agricultural facility. Scientists planned to live in Biosphere 2 with little contact with the outside world. The experiments carried out in Biosphere 2 were designed to study the relationship between living things and their environmentand to see whether humans might be able to live in space one day.

The mission was supposed to last 100 years, with two teams of scientists spending 50 years each in the facility. Instead, two teams made it just four years, and the scientists moved out in 1994. Though the live-in phase is over, research is still taking place in Biosphere 2, with a main focus on global warming.

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Illustrators

Mary Crooks, National Geographic Society

Editors

Jeannie Evers, Emdash Editing, Emdash Editing

Producer

National Geographic Society

other

Last Updated

October 19, 2023

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The biosphere is made up of the parts of Earth where life exists. The biosphere extends from the deepest root systems of trees to the dark environment of ocean trenches, to lush rain forests and high mountaintops.

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One of the main components of Earth's interdependent physical systems is the hydrosphere. The hydrosphere is the sum of Earth's water, in the ocean, the ground, on the surface, and in the air. Approximately 71 percent of Earth's surface is covered in water. Of all of that water, only about three percent is freshwater. An even smaller amount can be used as drinking water. Water cycles throughout the system continuously as the sun's radiation causes it to evaporate, rise into the atmosphere, condense, then fall as precipitation to be used or recycled.

Teach your students about the Earth's hydrosphere with the resources in this collection.

Subjects

Geology, Geography, Physical Geography

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One of the main components of Earth's interdependent physical systems is the hydrosphere. The hydrosphere is the sum of Earth's water, in the ocean, the ground, on the surface, and in the air. Approximately 71 percent of Earth's surface is covered in water. Of all of that water, only about three percent is freshwater.

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We live at the bottom of an invisible ocean called the atmosphere, a layer of gases surrounding our planet. Nitrogen and oxygen account for 99 percent of the gases in dry air, with argon, carbon dioxide, helium, neon, and other gases making up minute portions. Water vapor and dust are also part of Earth's atmosphere. Other planets and moons have very different atmospheres, and some have no atmospheres at all.

The atmosphere is so spread out that we barely notice it, yet its weight is equal to a layer of water more than 10 meters (34 feet) deep covering the entire planet. The bottom 30 kilometers (19 miles) of the atmosphere contains about 98 percent of its mass. The atmosphere-air-is much thinner at high altitudes. There is no atmosphere in space.

Scientists say many of the gases in our atmosphere were ejected into the air by early volcanoes. At that time, there would have been little or no free oxygen surrounding Earth. Free oxygen consists of oxygen molecules not attached to another element, like carbon (to form carbon dioxide) or hydrogen (to form water).

Free oxygen may have been added to the atmosphere by primitive organisms, probably bacteria, during photosynthesis. Photosynthesis is the process a plant or other autotroph uses to make food and oxygen from carbon dioxide and water. Later, more complex forms of plant life added more oxygen to the atmosphere. The oxygen in today's atmosphere probably took millions of years to accumulate.

The atmosphere acts as a gigantic filter, keeping out most ultraviolet radiation while letting in the sun's warming rays. Ultraviolet radiation is harmful to living things, and is what causes sunburns. Solar heat, on the other hand, is necessary for all life on Earth.

Earth's atmosphere has a layered structure. From the ground toward the sky, the layers are the troposphere, stratosphere, mesosphere, thermosphere, and exosphere. Another layer, called the ionosphere, extends from the mesosphere to the exosphere. Beyond the exosphere is outer space. The boundaries between atmospheric layers are not clearly defined, and change depending on latitude and season.

Troposphere

The troposphere is the lowest atmospheric layer. On average, the troposphere extends from the ground to about 10 kilometers (six miles) high, ranging from about six kilometers (four miles) at the poles to more than 16 kilometers (10 miles) at the Equator. The top of the troposphere is higher in summer than in winter.

Almost all weather develops in the troposphere because it contains almost all of the atmosphere's water vapor. Clouds, from low-lying fog to thunderheads to high-altitude cirrus, form in the troposphere. Air masses, areas of high-pressure and low-pressure systems, are moved by winds in the troposphere. These weather systems lead to daily weather changes as well as seasonal weather patterns and climate systems, such as El Niño.

Air in the troposphere thins as altitude increases. There are fewer molecules of oxygen at the top of Mount Everest, Nepal, for example, than there are on a beach in Hawai'i. This is why mountaineers often use canisters of oxygen when climbing tall peaks. Thin air is also why helicopters have difficulty maneuvering at high altitudes. In fact, a helicopter was not able to land on Mount Everest until 2005.

As air in the troposphere thins, temperature decreases. This is why mountaintops are usually much colder than the valleys beneath. Scientists used to think temperature continued to drop as altitude increased beyond the troposphere. But data collected with weather balloons and rockets have showed this is not the case. In the lower stratosphere, temperature stays almost constant. As altitude increases in the stratosphere, temperature actually increases.

Solar heat penetrates the troposphere easily. This layer also absorbs heat that is reflected back from the ground in a process called the greenhouse effect. The greenhouse effect is necessary for life on Earth. The atmosphere's most abundant greenhouse gases are carbon dioxide, water vapor, and methane.

Fast-moving, high-altitude winds called jet streams swirl around the planet near the upper boundary of the troposphere. Jet streams are extremely important to the airline industry. Aircraft save time and money by flying in jet streams instead of the lower troposphere, where air is thicker.

Stratosphere
The troposphere tends to change suddenly and violently, but the stratosphere is calm. The stratosphere extends from the tropopause, the upper boundary of the troposphere, to about 50 kilometers (32 miles) above Earth's surface.

Strong horizontal winds blow in the stratosphere, but there is little turbulence. This is ideal for planes that can fly in this part of the atmosphere.

The stratosphere is very dry and clouds are rare. Those that do form are thin and wispy. They are called nacreous clouds. Sometimes they are called mother-of-pearl clouds because their colors look like those inside a mollusk shell.

The stratosphere is crucial to life on Earth because it contains small amounts of ozone, a form of oxygen that prevents harmful UV rays from reaching Earth. The region within the stratosphere where this thin shell of ozone is found is called the ozone layer. The stratosphere's ozone layer is uneven, and thinner near the poles. The amount of ozone in the Earth's atmosphere is declining steadily. Scientists have linked use of chemicals such as chlorofluorocarbons (CFCs) to ozone depletion.

Mesosphere

The mesosphere extends from the stratopause (the upper boundary of the stratosphere) to about 85 kilometers (53 miles) above the surface of the Earth. Here, temperatures again begin to fall.

The mesosphere has the coldest temperatures in the atmosphere, dipping as low as -120 degrees Celsius (-184 degrees Fahrenheit or 153 kelvin). The mesosphere also has the atmosphere's highest clouds. In clear weather, you can sometimes see them as silvery wisps immediately after sunset. They are called noctilucent clouds, or night-shining clouds. The mesosphere is so cold that noctilucent clouds are actually frozen water vapor-ice clouds.

Shooting stars-the fiery burnout of meteors, dust, and rocks from outer space-are visible in the mesosphere. Most shooting stars are the size of a grain of sand and burn up before entering the stratosphere or troposphere. However, some meteors are the size of pebbles or even boulders. Their outer layers burn as they race through the mesosphere, but they are massive enough to fall through the lower atmosphere and crash to Earth as meteorites.

The mesosphere is the least-understood part of Earth's atmosphere. It is too high for aircraft or weather balloons to operate, but too low for spacecraft. Sounding rockets have provided meteorologists and astronomers their only significant data on this important part of the atmosphere. Sounding rockets are unmanned research instruments that collect data during suborbital flights.

Perhaps because the mesosphere is so little understood, it is home to two meteorological mysteries: sprites and elves. Sprites are reddish, vertical electrical discharges that appear high above thunderheads, in the upper stratosphere and mesosphere. Elves are dim, halo-shaped discharges that appear even higher in the mesosphere.

Ionosphere

The ionosphere extends from the top half of the mesosphere all the way to the exosphere. This atmospheric layer conducts electricity.

The ionosphere is named for ions created by energetic particles from sunlight and outer space. Ions are atoms in which the number of electrons does not equal the number of protons, giving the atom a positive (fewer electrons than protons) or negative (more electrons than protons) charge. Ions are created as powerful x-rays and UV rays knock electrons off atoms.

The ionosphere-a layer of free electrons and ions-reflects radio waves. Guglielmo Marconi, the "Father of Wireless," helped prove this in 1901 when he sent a radio signal from Cornwall, England, to St. John's, Newfoundland, Canada. Marconi's experiment demonstrated that radio signals did not travel in a straight line, but bounced off an atmospheric layer-the ionosphere.

The ionosphere is broken into distinct layers, called the D, E, F1, and F2 layers. Like all other parts of the atmosphere, these layers vary with season and latitude. Changes in the ionosphere actually happen on a daily basis. The low D layer, which absorbs high-frequency radio waves, and the E layer actually disappear at night, which means radio waves can reach higher into the ionosphere. That's why AM radio stations can extend their range by hundreds of kilometers every night.

The ionosphere also reflects particles from solar wind, the stream of highly charged particles ejected by the sun. These electrical displays create auroras (light displays) called the Northern and Southern Lights.

Thermosphere

The thermosphere is the thickest layer in the atmosphere. Only the lightest gases-mostly oxygen, helium, and hydrogen-are found here.

The thermosphere extends from the mesopause (the upper boundary of the mesosphere) to 690 kilometers (429 miles) above the surface of the Earth. Here, thinly scattered molecules of gas absorb x-rays and ultraviolet radiation. This absorption process propels the molecules in the thermosphere to great speeds and high temperatures. Temperatures in the thermosphere can rise to 1,500 degrees Celsius (2,732 degrees Fahrenheit or 1,773 kelvin).

Though the temperature is very high, there is not much heat. How is that possible? Heat is created when molecules get excited and transfer energy from one molecule to another. Heat happens in an area of high pressure (think of water boiling in a pot). Since there is very little pressure in the thermosphere, there is little heat transfer.

The Hubble Space Telescope and the International Space Station (ISS) orbit Earth in the thermosphere. Even though the thermosphere is the second-highest layer of Earth's atmosphere, satellites that operate here are in "low-Earth orbit."

Exosphere

The fluctuating area between the thermosphere and the exosphere is called the turbopause. The lowest level of the exosphere is called the exobase. At the upper boundary of the exosphere, the ionosphere merges with interplanetary space, or the space between planets.

The exosphere expands and contracts as it comes into contact with solar storms. In solar storms particles are flung through space from explosive events on the sun, such as solar flares and coronal mass ejections (CMEs).

Solar storms can squeeze the exosphere to just 1,000 kilometers (620 miles) above the Earth. When the sun is calm, the exosphere can extend 10,000 kilometers (6,214 miles).

Hydrogen, the lightest element in the universe, dominates the thin atmosphere of the exosphere. Only trace amounts of helium, carbon dioxide, oxygen, and other gases are present.

Many weather satellites orbit Earth in the exosphere. The lower part of the exosphere includes low-Earth orbit, while medium-Earth orbit is higher in the atmosphere.

The upper boundary of the exosphere is visible in satellite images of Earth. Called the geocorona, it is the fuzzy blue illumination that circles the Earth.

Extraterrestrial Atmospheres

All the planets in our solar system have atmospheres. Most of these atmospheres are radically different from Earth's, although they contain many of the same elements.

The solar system has two major types of planets: terrestrial planets (Mercury, Venus, Earth, and Mars) and gas giants (Jupiter, Saturn, Uranus, and Neptune).

The atmospheres of the terrestrial planets are somewhat similar to Earth's. Mercury's atmosphere contains only a thin exosphere dominated by hydrogen, helium, and oxygen. Venus' atmosphere is much thicker than Earth's, preventing a clear view of the planet. Its atmosphere is dominated by carbon dioxide, and features swirling clouds of sulfuric acid. The atmosphere on Mars is also dominated by carbon dioxide, although unlike Venus, it is quite thin.

Gas giants are composed of gases. Their atmospheres are almost entirely hydrogen and helium. The presence of methane in the atmospheres of Uranus and Neptune give the planets their bright blue color.

In the lower atmospheres of Jupiter and Saturn, clouds of water, ammonia, and hydrogen sulfide form clear bands. Fast winds separate light-colored bands, called zones, from dark-colored bands, called belts. Other weather phenomena, such as cyclones and lightning, create patterns in the zones and belts. Jupiter's Great Red Spot is a centuries-old cyclone that is the largest storm in the solar system.

The moons of some planets have their own atmospheres. Saturn's largest moon, Titan, has a thick atmosphere made mostly of nitrogen and methane. The way sunlight breaks up methane in Titan's ionosphere helps give the moon an orange color.

Most celestial bodies, including all the asteroids in the asteroid belt and our own moon, do not have atmospheres. The lack of an atmosphere on the Moon means it does not experience weather. With no wind or water to erode them, many craters on the Moon have been there for hundreds and even thousands of years.

The way a celestial body's atmosphere is structured and what it's made of allow astrobiologists to speculate what kind of life the planet or moon may be able to support. Atmospheres, then, are important markers in space exploration.

A planet or moon's atmosphere must contain specific chemicals to support life as we know it. These chemicals include hydrogen, oxygen, nitrogen, and carbon. Although Venus, Mars, and Titan have similar atmospheric gases, there is nowhere in the solar system besides Earth with an atmosphere able to support life. Venus' atmosphere is far too thick, Mars' far too thin, and Titan's far too cold.

Fast Fact

Ingredients for Life
Scientists have gathered enough information about other planets in our solar system to know that none can support life as we know it. Life is not possible without a stable atmosphere containing the right chemical ingredients for living organisms: hydrogen, oxygen, nitrogen, and carbon. These ingredients must be balanced-not too thick or too thin. Life also depends on the presence of water.

Jupiter, Saturn, Uranus, and Neptune all have atmospheres made mostly of hydrogen and helium. These planets are called gas giants, because they are mostly made of gas and do not have a solid outer crust.

Mercury and Mars have some of the right ingredients, but their atmospheres are far too thin to support life. The atmosphere of Venus is too thick-the planet's surface temperature is more than 460 degrees Celsius (860 degrees Fahrenheit).

Jupiter's moon Europa has a thin atmosphere rich with oxygen. It is likely covered by a huge ocean of liquid water. Some astrobiologists think that if life exists elsewhere in the solar system, it will be near vents at the bottom of Europa's ocean.

Fast Fact

Magnetosphere
Earths magnetosphere is not considered part of the atmosphere. The magnetosphere, formed by the Earths magnetic fields, protects the atmosphere by preventing it from being blown away by powerful solar wind.

Fast Fact

Atmospheric Orbit
Although the International Space Station orbits in the thermosphere, most satellites orbit the Earth outside its atmosphere. GPS satellites, for instance, are in orbit more than 20,000 kilometers (12,400 miles) above the Earth.

Media Credits

The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.

Illustrators

Mary Crooks, National Geographic Society

Editors

Jeannie Evers, Emdash Editing, Emdash Editing

Producer

National Geographic Society

other

Last Updated

October 19, 2023

For information on user permissions, please read our Terms of Service. If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher. They will best know the preferred format. When you reach out to them, you will need the page title, URL, and the date you accessed the resource.

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We live at the bottom of an invisible ocean called the atmosphere, a layer of gases surrounding our planet. Nitrogen and oxygen account for 99 percent of the gases in dry air, with argon, carbon dioxide, helium, neon, and other gases making up minute portions.

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The five systems of Earth (geosphere, biosphere, cryosphere, hydrosphere, and atmosphere) interact to produce the environments we are familiar with.

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The third planet from the Sun is Earth, the home of all known life. While it shares many characteristics with other planets, its physical properties and history allow it to…

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READ: What Is the Biosphere? (article) | Khan Academy

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The History of a Word

Sometimes the history of a word can tell us a lot about what the word means. The study of words even has its own name: etymology. Often, a closer look at a word unfolds into another story, one that may connect to other people and other scientific studies.

The word biosphere was first used by English-Austrian geologist Eduard Suess (1831-1914) more than a hundred years ago in a four-volume work entitled Das Antlitz der Erde, or The Face of the Earth (1885-1908). Suess is also credited with being the first person to propose the existence of the supercontinent Gondwanaland and the ancient Tethys Ocean, based upon his work studying fossils in the Alps and his knowledge of the fossils of Glossopteris ferns that were found on several different continents.

At the time, no one knew about plate tectonics (German meteorologist Alfred Wegener didn't put forth his theory on continental drift until 1912, a couple of years before Suess died), and the best explanation Suess could offer for the presence of marine fossils in the mountains was that the waters of the Tethys Ocean had flooded the whole Earth, not that the continents had actually drifted apart and changed. This is a great example of how limited evidence can sometimes lead scientists to settle on incorrect conclusions. It also demonstrates how the work of one person can build on that of others, collectively leading to new discoveries about the world around us.

Suess combined bio, meaning "life," and sphere, referencing the Earth's rounded surface, to express the portion of the Earth that supported life. He invented the word because he felt it was important to try to understand life as a whole rather than singling out particular organisms. He wrote in Das Antlitz der Erde:

The plant, whose deep roots plunge into the soil to feed, and which at the same time rises into the air to breathe, is a good illustration of organic life in the region of interaction between the upper sphere and the lithosphere, and on the surface of continents it is possible to single out an independent biosphere.

​As our knowledge of life on the planet evolves, we've come to use the word biosphere as a way of explaining the entire intertwined network of life on Earth. This concept combines an understanding of geology, knowledge of the distinct layers that make up the Earth and its atmosphere, and an awareness of the biodiversity surrounding us. We can think of the biosphere as the habitat, or home, for all life on our planet, in all its forms, and with all its intricate biological and geological relationships.

Biosphere = the network of all life on Earth

Worlds Within Worlds

The biosphere is incredibly small - just a thin layer around a medium-size planet. But it's also incredibly large, when you consider all of the different living things and our planet's vast expanses of water and land. As with most things that seem large and encompassing, it's possible to break down the biosphere and to use other words to describe specific environments or habitats.

These smaller areas are called "ecosystems," and they are characterized by particular geologic or climatic features that accommodate certain forms of life. Oceans, jungles, and mountain ranges can be ecosystems, but even more specific places can be their own ecosystems. Think of a cave, a river or river valley, a coral reef, a city, or the "vent communities" that surround black smokers on the ocean floor. Altitude, latitude, longitude, climate, soils, and terrain can all contribute to the distinct features of an ecosystem - the Earth's geologic processes have produced a multitude of diverse environments. The biosphere boasts incredible diversity and, even in extreme environmental conditions, astounding examples of life's flexibility and determination.

Every organism - from baboons to bacteria, desert snakes to deep-sea sponges - has a specialized way to make a living as it vies for resources and energy and reproduces within its own environment. Examining these individual ecosystems, using biology and geology, reveals the many complex relationships between life and the planet we all share.

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READ: What Is the Biosphere? (article) | Khan Academy

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The geosphere includes the rocks and minerals on Earth - from the molten rock and heavy metals in the deep interior of the planet to the sand on beaches and peaks of mountains. The geosphere also includes the abiotic (non-living) parts of soils and the skeletons of animals that may become fossilized over geologic time.

Beyond these parts, the geosphere is about processes. The processes of the rock cycle such as metamorphism, melting and solidification, weathering, erosion, deposition, and burial are responsible for the constant recycling of rocks on Earth between sedimentary, igneous, and metamorphic states.

Sedimentary rocks are formed via weathering and transport of existing rocks, and then deposition, cementation, and compaction into sedimentary rock.

Igneous rocks are formed by the cooling and crystallization of molten rock.

Metamorphic rocks are formed when heat or pressure is applied to other rocks.

The primary agent driving these processes is the movement of Earth's tectonic plates, which creates mountains, volcanoes, and ocean basins. Changes in the rate that rocks are made and destroyed can have a profound effect on the planet. As the rate of plate tectonic movements has changed over geologic time scales, the rock cycle has changed as well, and these changes have been able to affected climate. For example, at times when the rate of plate movements has been high, there is more volcanic activity, which releases more particles into the atmosphere. Faster plate tectonic movements also mean more mountains are built in areas where plates converge. As rocks are uplifted into mountains, they start to erode and dissolve, sending sediments and nutrients into waterways and impacting the ecosystems for living things.

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The geosphere includes the rocks and minerals on Earth - from the molten rock and heavy metals in the deep interior of the planet to the sand on beaches and peaks of mountains. Beyond these parts, the geosphere is about the processes responsible for the constant recycling of rocks on Earth.

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DEFINITION OF EARTH'S SPHERES

The spheres are the four subsystems that make up the planet Earth. They are called spheres because they are round, just like the Earth. The four spheres are the geosphere (all the rock on Earth), hydrosphere (all the water on Earth), atmosphere (all the gases surrounding Earth), and biosphere (all the living things on Earth).
To better understand how the 4 spheres of the Earth work....

LET'S BREAK IT DOWN!

The four spheres interact.

The spheres interact to effect Earth's systems and processes, and they are constantly changing each other.

For example, ocean currents (hydrosphere) affect air temperature (atmosphere): The Gulf Stream is a powerful water current in the Atlantic Ocean. It's warm water moderates the temperatures on the east coast of the USA.

Another example of how the spheres affect each other is through erosion. Erosion happens in the desert when wind (atmosphere) shapes the sand in the geosphere. Water (hydrosphere) can also shape land, such as in the formation of the Grand Canyon.

EXAMPLES OF EARTH'S 4 SPHERES

VOCABULARY ON EARTH'S SPHERES

After pieces of the earth are broken down through weathering, those pieces are moved through Erosion. Erosion is the process of moving things from one place to another.

Naturally occurring rocks that look like a mushroom. They can be formed when sand gets carried by wind and hits the rock. This weathers the bottom of the rock more than the top.

A solid form of carbon dioxide that is very cold and turns directly from a solid to a gas.

DISCUSSION QUESTIONS ON EARTH'S SPHERES

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Geosphere, Biosphere, Hydrosphere & Atmosphere | Fun Science Lesson

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Did you know that there are 4 spheres of earth that all interact together? Learn abuot Earth's four spheres for kids in 3rd, 4th and 5th grade!

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Atmosphere | Aspen Global Change Institute

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Atmosphere | Aspen Global Change Institute

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Biosphere | Aspen Global Change Institute

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Biosphere | Aspen Global Change Institute

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The Geosphere | Aspen Global Change Institute

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What is the Geosphere?

The geosphere is the earth itself: the rocks, minerals, and landforms of the surface and interior. Below the crust - which varies in depth from about 5 km beneath the ocean floor to up to 70 km below the land surface, temperatures are high enough for deformation and a paste-like flow of elements. At one time, roughly 200 million years ago, the continents were joined together in a supercontinent called Pangaea, but since then tectonic plates have slowly separated, creating the arrangement of the continents we are accustomed to today.

Plate tectonic movement is ongoing, and humans can witness its sometimes violent activity in the form of earthquakes and volcanoes. More regularly, however, human interaction with the dynamic geosphere comes in the form of surface erosion, our use of arable land for farming, and excavations for the construction of buildings, roads, and mines.

How does the geosphere interact in the earth system?

Evolution of the continents. Fast-forward 200 million years from the time of Pangaea to the creation of the modern-day continents. (Credit: ARC Science Simulations)

While seemingly static, the geosphere is in fact a very active player in the earth's systems, affecting the atmosphere and the oceans, as well as critical processes such as the water cycle and biogeochemical cycles. For instance, the types of minerals contained in soils - the results of geologic processes - help to determine the vegetative cover and ecosystems on the soil surface. Carbon - an essential element of life - is bound in organic matter and is carried to the ocean via wind and water erosion where eventually it becomes part of the ocean floor. Tectonic movement carries ocean deposits into the earth's interior. On geologic timescales, volcanic activity can vent the stored carbon to the Earth's atmosphere as carbon dioxide. The carbon cycle is one of the key cycles linking the geosphere, atmosphere, hydrosphere, and biosphere.

The inner core of the earth contains liquid iron. Its motion is thought to drive the earth's magnetic field - the magnetosphere - which extends far beyond the atmosphere, protecting Earth and its biosphere from solar wind and cosmic radiation. This layer is extremely hot and advances in geothermal technology could some day enable us to harness greater amounts of heat energy from within the crust and convert it to electricity at the surface.

Soy Plantation, Amazon Brazil. With the aid of fossil fuel-powered machinery, man can make sweeping changes to the natural landscape.

How do humans interact with the geosphere?

Aside from surface disturbances such as excavations and agriculture, humans have a fairly minor impact on the workings and scale of the geosphere. Humans still live largely at the mercy of powerful geologic forces. The 2010 Haiti earthquake is just one of many examples of the impact of these forces. While we may never be able to stop earthquakes or volcanoes, studying their mechanics can enable us to better understand their dynamics so that we may continue to develop means for reducing risk to homes and people when they occur.

Journal Activity

Materials: Notebook, paper and pencil or dedicated computer file where you can keep your work.

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The Geosphere | Aspen Global Change Institute

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The geosphere is the earth itself: the rocks, minerals, and landforms of the surface and interior. Below the crust - which varies in depth from about 5 km beneath the ocean floor to up to 70 km below the land surface, temperatures are high enough for deformation and a paste-like flow of elements.

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The Hydrosphere | Aspen Global Change Institute

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What is the hydrosphere?

The hydrosphere is the sum of all water on Earth and the water cycle that distributes it around the planet. Earth is unique in the solar system for its abundant surface waters. Our orbital distance from the sun, in addition to our unique atmosphere, gives Earth the right temperature in our middle-aged solar system to have water as a liquid, and lots of it. Venus is too hot, Mars is too cold. Earth is just right. Noted astronomer Carl Sagan described Earth as seen from distant space as a "pale blue dot," signaling our planet as an outpost of life. It's because of the hydrosphere that life flourishes on Earth.

Just as important as the existence of water is the hydrologic cycle that moves water around the globe. Driven by solar energy, surface waters evaporate into the atmosphere, condense, and fall back to the surface as precipitation, shaping continents, creating rivers, and filling lakes. This process has eroded billions of tons of surface material from the continents to the oceans, forming the major river deltas. By far, most of the hydrosphere is salt water - around 97 percent - but the 3 percent that is fresh is critical for terrestrial and fresh water species.

How is the hydrosphere changing?
Human contributions to greenhouse gases in the atmosphere are warming the earth's surface - a process which is projected to increase evaporation of surface water and accelerate the hydrologic cycle. In turn, a warmer atmosphere can hold more water vapor. Some evidence suggests global warming is already responsible for more extreme precipitation events. Precipitation in a warming world is also projected to lead to departures from current timing and patterns of rainfall distribution.Water Distribution Water on Earth. Most of the water on Earth is either salty or inaccessible to humans. Only 3% is fresh, and of that only about 32% is unfrozen.

The variable hydrosphere

Precipitation around the globe is highly variable - from deserts (0 to 50 cm per year) to wet rainforests (125-660 cm per year). This variability is a key attribute of productive terrestrial ecosystems. While most precipitation evaporates from and falls onto the oceans, precipitation on land dominates as a key determinant of terrestrial biological zones of the Earth. While some organisms called extremophiles have found ways to adapt to very dry, hot, frozen, or low or high pH environments, the most abundant ecosystems on Earth exist where temperatures are tropical to temperate, nutrients are plentiful, and water is available.

Global Precipitation This animation illustrates the variability of precipitation around the globe. Tropical areas in South America and Africa, for instance, may receive up to 15 mm of rain each day, while arid regions like the Sahara receive little to none at all.(Source: NASA)

How is the hydrosphere changing?

Human contributions to greenhouse gases in the atmosphere are warming the earth's surface - a process which is projected to increase evaporation of surface water and accelerate the hydrologic cycle. In turn, a warmer atmosphere can hold more water vapor. Some evidence suggests global warming is already responsible for more extreme precipitation events. Precipitation in a warming world is also projected to lead to departures from current timing and patterns of rainfall distribution.

The Florida Keys connected by Highway One. The landscapes we enjoy today were once quite different. For example, 125,000 years ago, the Florida Keys were an underwater coral reef. Then, as the Earth settled into an ice age, sea levels fell, leaving the islands up to 120 m above sea level. Today, the low-lying islands are now at risk of re-submergence due to sea level rise that is the result of human-caused global warming.

While the exact changes are difficult to project, it is highly likely that some places will get drier while other places get wetter over the course of the 21st century as a result of global warming. For example, current climate models indicate that with global warming, high latitudes in the Northern Hemisphere are likely to see more precipitation.

Changes in types of precipitation may occur as well. Some precipitation may shift to rain rather than snow. This would decrease mountain snowpack and affect the timing and quantity of seasonal runoff. Changes in the patterns of spring runoff from major snow-fed river systems, such as those that flow from the Himalayas, will impact the lives and livelihoods of upwards of a billion people who depend upon snowmelt-fed rivers for domestic, agricultural, and industrial use.

As the Earth warms, so too will the ocean. As water warms, it expands. Expansion of warming water makes up about half of the present rise in sea level. The rest of the sea level rise we are currently witnessing is the result of land-based snow and ice melting into the ocean. The melt water component of sea level is expected to make up a more significant component of sea level rise as this century unfolds. The 2013 Intergovernmental Panel on Climate Change report found a 0.19 m rise in sea level between 1901 and 2010 and projected an additional 0.52-0.98 m of sea level rise over this century. However, recent research suggests that the amount of glacier melt could be significantly greater, raising sea level a meter or more. Island nations with little elevation above sea level are in peril, as are many countries with large coastal populations, such as the United States. Lowland settlements will be faced with a choice: whether to hold the line with engineered structures or retreat to higher ground.

IPCC 2013 sea-level rise projections: Climate change is more than just global warming. Forecasts predict shifts in precipitation and run-off patterns that will affect agricultural practices and human livelihoods. (Source: IPCC 2014)

Journal Activity

Materials: notebook, paper and pencil or dedicated computer file where you can keep your work.

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The Hydrosphere | Aspen Global Change Institute

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The hydrosphere is the sum of all water on Earth and the water cycle that distributes it around the planet. Earth is unique in the solar system for its abundant surface waters. Our orbital distance from the sun, in addition to our unique atmosphere, gives Earth the right temperature in our middle-aged solar system to have water as a liquid, and lots of it.

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Geosphere: Importance, Parts and Examples of Geosphere | Earth Eclipse

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Geosphere: Importance, Parts and Examples of Geosphere | Earth Eclipse

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Geosphere is nothing but the rock-hard outer covering along with the internal crust of the Earth. Geosphere is the only composition we find in the different layers of the Earth like the lithosphere, cryosphere, hydrosphere, and biosphere.

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Structure of the Earth! - National Geographic Kids

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The secrets buried inside our planet are revealed by recording and studying things called seismic waves. Caused by things like earthquakes, explosions and the movement of our oceans, there are two types of seismic wave - a shear wave, which won't travel through liquid; and a pressure wave, which moves through both liquid and solids. These waves show that the Earth is made from five layers: the inner and outer core, the lower and upper mantle, and the crust.

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The Earth's inner core is a huge metal ball, 2,500km wide. Made mainly of iron, the temperature of the ball is 5,000°C to 6,000°C - that's up to 6,000 times hotter than our atmosphere and scorching enough to make metal melt! The metal at the inner core stays solid because of the incredible pressure surrounding it.

Temperature: 4,000°C - 6,000°C
State: Liquid
Composition: iron, nickel, sulphur and oxygen

This liquid layer of iron and nickel is 5,150km deep. The outer core flows around the centre of the Earth, and the movement of the metals creates our planet's magnetic field.

Lower Mantle

The lower mantle is found between 670km and 2,890km below the surface, and is made from solid rock. The rock is hot enough to melt, but is solid because of the pressure pushing down on it.

Upper Mantle

Temperature: 1,400°C - 3,000°C
State: liquid / solid
Composition: iron, oxygen, silicon, magnesium and aluminium

This layer is up to 670km below the Earth's surface. The lower part of the upper mantle is made from both solid and melted rock (liquid), while the rock in the upper region is stiffer, because it's cooler.

Temperature: Around 22°C
State: Solid
Composition: Oceanic crust made up of iron, oxygen, silicon, magnesium and aluminium.
Continental crust made up of granite, sedimentary rocks and metamorphic rocks.

The Earth's surface is covered by its thinnest layer, the crust. Land is made of continental crust, which is 8km to 70km thick and made mostly from a rock called granite. The layer beneath the ocean bed is made of oceanic crust, which is about 8km thick and made mainly from a rock called basalt.

By studying rocks and meteorites (rocks from space), scientists believe the Earth is about 4.5 billion years old!

Illustration: Getty Images UK

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Structure of the Earth! - National Geographic Kids

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Learn all about the structure of the Earth here at National Geographic Kids! Join us as we explore the different layers - the crust, upper mantle, lower mantle, outer core and inner core...

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The movement of water throughout Earth can be understood as a cycle where H20 moves from one state of matter to another. Use these standards-aligned resources to teach middle schoolers more about condensation, precipitation, and weather patterns that are affected by, and a part of, the water cycle.