Biosphere and Earth's Systems

The Biosphere

• The biosphere is a thin layer of Earth suitable for life.
• It's made up of three interacting components: atmosphere, lithosphere, and hydrosphere.
• Atmosphere is a layer of gases surrounding Earth.

Weather & Climate

• Weather describes short-term conditions (temperature, air pressure, cloud cover, precipitation, humidity).
• Climate is the average weather over a long period (at least 30 years).
• Examples: Calgary is warmer than Northern Alberta.

The Earth

• Atmosphere: The layer of gases (mainly Nitrogen and Oxygen) surrounding Earth.
• Lithosphere: The solid portion of Earth (rocks, minerals and elements).
• Hydrosphere: All water on Earth (liquid, vapor, ice).

Atmosphere

• The atmosphere extends 500 km from Earth's surface.
• It is a mixture of gases.
• Nitrogen is the most abundant gas, required for plant growth.
• Oxygen is essential for life and many chemical reactions.
• Water vapor is present, although levels vary.

Lithosphere

• The lithosphere is the solid portion of the biosphere.
• It extends from the surface to about 100 km.
• Further down is the upper mantle, which is partially molten.
• The lithosphere sits on land and beneath oceans.
• It is warmed by the Sun's energy and the molten mantle materials.

Hydrosphere

• The hydrosphere encompasses all water on Earth.
• Approximately 97% is saltwater in oceans/seas.
• The remaining 3% is fresh water (lakes, rivers, aquifers, water vapor, glaciers).
• The hydrosphere, like the lithosphere, is mostly warmed by the Sun and the mantle.

Biosphere Interactions

• Biosphere components interact and overlap.
• Water vapor is part of the atmosphere and hydrosphere.
• Soil (part of the lithosphere) contains water, essential for life.
• The margins of hydrosphere and lithosphere support productive aquatic habitats.
• Plants and animals exchange gases with the atmosphere, regardless of location.

Solar Energy

• Nearly all Earth's energy comes from the Sun.
• Some solar energy is stored as chemical energy by plants.
• Most solar energy is converted to thermal energy.
• Thermal energy is the energy due to the movement of molecules.
• Different areas of Earth receive different amounts of solar energy.

Radiant Energy

• Solar energy is transmitted as electromagnetic waves (includes radio, visible light).
• The electromagnetic spectrum spans various wavelengths, with different energies per wave (gamma rays > radio waves).

Insolation

• Insolation is the amount of solar energy received by a location.
• Latitude (imaginary lines parallel to the equator) and the specific characteristics of the lithosphere, atmosphere, and hydrosphere strongly influence insolation.
• Insolation is influenced by a region's position relative to the sun (near the equator vs closer to the poles).

Angle of Inclination

• Earth's axis is tilted 23.5 degrees relative to the plane of its orbit.
• This tilt causes variations in the amount of solar energy received at different latitudes throughout the year (seasons).
• The consequences of this tilt affect the amount of solar energy reaching Earth's surface

Earth's Orbit and Angle of Inclination

• Earth orbits the sun annually.
• The tilt of Earth's axis (23.5°) during its orbit causes variations in the amount of solar radiation reaching different areas throughout the year (seasons).
• The north pole is tilted toward the sun during summer, leading to increased insolation (solar energy).

Latitudes

• Earth's surface is divided into latitudes (imaginary lines).
• Latitude influences daylight hours in various locations.
• At higher latitudes, there are greater variations in daylight hours between seasons.

Insolation and the Angle of Incidence

• The angle at which sunlight strikes Earth's surface affects insolation.
• A more direct angle (near the equator) means more energy per square kilometer than at higher latitudes.

Absorption & Reflection

• When solar radiation hits Earth, it can either be absorbed or reflected.
• Reflection changes the direction of the energy.
• Absorption converts the energy into another form (typically thermal energy), increasing the temperature.

Albedo

• Albedo is the percentage of solar radiation a surface reflects.
• Light-colored surfaces (e.g., snow) have high albedo (i.e. reflect more radiation).
• Dark surfaces (e.g., forests) have low albedo (i.e. more absorb).
• Albedo is an important factor affecting climate change, as melting ice reduces Earth's reflection and increases absorption.

Natural Greenhouse Effect

• The natural greenhouse effect is due to gases absorbing thermal energy.
• This process maintains Earth's temperature range.
• Greenhouse gases, such as water vapor, CO2, N₂O, and CH4, absorb and re-emit infrared radiation, trapping heat. Without the greenhouse effect, Earth's average temperature would be much lower.

Net Radiation Budget

• A net radiation budget is the difference between incoming and outgoing radiation.
• Incoming radiation includes all the sun's energy that arrives at Earth's surface.
• Outgoing radiation includes the energy that Earth's system radiates back out to space.

Explore the interactions among the biosphere, atmosphere, lithosphere, and hydrosphere in this quiz. Learn about weather and climate distinctions, as well as the essential elements that support life on Earth. Test your understanding of these fundamental concepts in Earth science.