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).
Geo means “earth.” The Earth’s geosphere (sometimes called the lithosphere) is the portion of the earth that includes rocks and minerals. It starts at the ground and extends all the way down to Earth’s core.
We rely on the geosphere to provide natural resources and a place to grow food. Volcanos, mountain ranges, and deserts are all part of the geosphere. Put simply, without the geosphere, there would be no Earth!
Hydro means “water.“ The hydrosphere includes the oceans, rivers, lakes, groundwater, and water frozen in glaciers. 97% of water on Earth is found in the oceans. Water is one of the most important substances needed for life and makes up about 90% of living things. Without water, life would not be possible.
Atmos means “air.” The atmosphere includes all the gases surrounding the Earth. We often call the atmosphere “air.” All planets have an atmosphere, but Earth is the only planet with the correct combination of gases to support life.
The atmosphere consists of five layers and is responsible for Earth’s weather. Even though it seems like air is made of nothing, it consists of particles too small to be seen. All these particles have weight that push down on Earth. The weight of air above us is called air pressure.
Bio means “life.” The biosphere is made up of all the living things on Earth and it includes fish, birds, plants, and even people.
The living portion of the Earth interacts with all the other spheres. Living things need water (hydrosphere), chemicals from the atmosphere, and nutrients gained by eating things in the biosphere.
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.
Humans have a huge impact on all spheres. Negative impacts, such as burning fossil fuels, pollute the atmosphere. Piling up our waste in landfills affects the geosphere. Pumping waste into the oceans harms the hydrosphere. And overfishing and habitat destruction can reduce the diversity of living things in the biosphere.
However, people everywhere are working to change things. Recycling efforts are increasing all over the world, and companies are finding new ways to reduce fossil fuels. In the US alone, people are recycling six times more than a generation ago.
