Environmental Science: Earth SystemsGeosphere, Biosphere, Atmosphere and
Hydrosphere
Dynamic EarthThe earth is broken down into rock (geosphere), air (atmosphere),
water (hydrosphere), Living things (biosphere) interact with each other.
These are all divided into the different parts- Geosphere
- Atmosphere
- Hydrosphere
- Biosphere
The Geosphere: the solid part of the Earth that consists of all rock and the soils
and sediments on the surface.
- Most of the Geosphere is located in the Earth’s interior
- Studying below the crust is very difficult
o They measure the density of the Earth with the use of a
seismograph.
The Crust: This is where we LIVE
This outermost layer
The Crust is made up of continents and ocean
Continental is 20 – 30 mi thick
Oceanic is 3-6 mi thick
The Mantle:
The layer found right under the crust
1800 miles thick
500- 4000 degrees celcius
made up of rocks and it is not as light as the crust but not as dense of the core
has a liquid layer that makes up the lava that erupts out of volcanoes.
The Lithosphere: consists of the CRUST and the UPPER PART OF THE MANTLE
- The Lithosphere is divided into large pieces of earth called: Tectonic
Plates
The Asthenosphere: This is the layer that is below the Lithosphere
-
It consists of the “plastic “ part of the mantle
Rock flows smoothly like melted plastic
Allowing the plates of Earth to move.
Plate Movement:
-
Plates can either:
o Pull apart
 or
o Squeeze together
 or
o Slip past each other
Major geological activity caused can be
-Volcano
-Earthquake- faults
-Mountains
-Ocean Ridges
Volcanoes:
Mountain build from magma
Volcanoes are usually found at plate boundaries
Can occur on land or in the ocean
Global Effects of Geological Events:
Dust and Chemicals from volcanoes enter atmosphere
Chemicals become part of runoff
Global temperature decreases
Erosion- Wearing down of rocks
o Water
o Wind
The Atmosphere
-
Consists of a mixture of gases that surround earth
Nitrogen, Oxygen, Carbon Dioxide and other gases
Gases are constantly added and removed from the atmosphere
Insulates the Earth’s surface
Composition of the Atmosphere:
Nitrogen- 78%
Oxygen- 21%
Argon, Carbon Dioxide, Methane and Water Vapor- 1%
Layers of the Atmosphere:
The Troposphere- is the closest to the Earth’s surface.
This is where weather occurs
Temperature decreases as you move further into the Troposphere.
Stratosphere:
Is the layer above the Troposphere
Temperature increases as you go further into the Stratosphere
This happens because the ozone absorbs the sun’s UV light and warms the air
(O
Ozone
3) is a molecule made of 3 oxygen atoms
Ozone layer limits the amount of UV light that reaches the Earth
The Greenhouse Effect:
-
Sunlight heats the surface of the Earth
The surface radiates the heat back to the atmosphere, where some heat
escapes into space
The rest of the heat is absorbed by greenhouse gasses which heats the air
Heat then radiates back to the Earth
Gasses trap the heat near the Earth- Greenhouse Effect
The Hydrosphere:
Includes all water on or near the Earths surface
The Biosphere:
-
The narrow layer around Earth’s surface in which life can exist
Consists of the upper most part of the Geosphere, most of the
hydrosphere and the lower part of the atmosphere.