Earth Systems: Geosphere, Atmosphere, and Hydrosphere

Asthenosphere

Semi-solid, pliable layer below the lithosphere that can flow slowly under pressure.

Lithosphere

Strong, rigid rocks that break when they move, includes oceanic crust, continental crust, and some of the upper mantle.

Lava

Molten rock on the Earth's surface.

Magma

Molten rock in the geosphere.

Greenhouse gas

A gas that can absorb and radiate energy causing the temperature to rise, such as CO2.

Troposphere

The lowest layer of Earth's atmosphere where weather occurs.

Stratosphere

The layer of the atmosphere above the troposphere, containing the ozone layer.

Mesosphere

The layer of the atmosphere above the stratosphere, where temperatures decrease with altitude.

Thermosphere

The layer of the atmosphere above the mesosphere, characterized by high temperatures.

Ionosphere

A region of the atmosphere that contains a high concentration of ions and free electrons.

Ozone

A molecule composed of three oxygen atoms, found in the ozone layer.

Ozone Layer

A region of Earth's stratosphere that absorbs most of the sun's harmful ultraviolet radiation.

Core

The innermost part of the Earth, composed mainly of iron and nickel.

Mantle

The part of the Earth's internal structure between the crust and core, making up about 2/3 of Earth's total mass.

Crust

The thin outermost layer of the Earth, containing rocks that can be examined at Earth's surface.

Continental Crust

Outermost part of the Earth's geosphere that makes up the landmasses, approximately 12 to 25 miles thick.

Granite

A type of rock containing less-dense elements, lighter in color, found in continental crust.

Oceanic Crust

The crust under the oceans, approximately 3 to 6 miles thick.

Basalt

Denser, volcanic rock that is dark in color, found in oceanic crust.

Mohorovićić discontinuity

Moho - place in the geosphere where seismic waves abruptly accelerate, marking the boundary between the crust and upper mantle.

Volatiles

Components in magma that erupt from volcanoes in the form of lava.

Outgassing

Volatile components released from the interior surface and atmosphere.

Atmosphere

The envelope of gases (air) that surround the Earth, extending from Earth's surface upward for many hundreds of kilometers.

Geosphere

Solid Earth with its deep molten portions, responsible for building mountain chains and creating ocean basins.

Biosphere

The global sum of all ecosystems, where life exists on Earth.

Hydrosphere

All of the water on Earth, including oceans, rivers, lakes, and water vapor.

Atmospheric Structure

Variations in composition and temperature that define the atmosphere's structure, typically around 480 km (300 mi) thick.

Troposphere

The lowest part of the atmosphere where weather occurs.

Stratosphere

The second layer of the atmosphere where temperatures increase upward.

Mesosphere

The third layer of the atmosphere, where temperatures decrease upward.

Thermosphere

The outermost layer of the atmosphere.

Atmospheric Layers

Four layers defined by temperature variations: troposphere, stratosphere, mesosphere, and thermosphere.

Dynamic Atmosphere

The troposphere is the most dynamic place within the atmosphere.

Atmospheric Mass

About half of the mass of the atmosphere is in the lower 5 km (3 mi) of the troposphere.

Temperature Increase

In the stratosphere, temperatures increase upward compared to the underlying troposphere.

Boundary Zone

The stratosphere prevents air from rising and crossing their boundary zone.

Temperature Decrease

In the mesosphere, temperatures decrease upward.

Gas Molecules in Mesosphere

The concentration of gas molecules in the mesosphere is low but sufficient to cause significant effects.

Meteors

Friction with gas molecules in the mesosphere causes meteors to heat up, observable as shooting stars.

Thermosphere Temperature

In the thermosphere, temperatures increase upward due to intense solar radiation interaction with sparse gas molecules.

Ions

An atom or molecule with an electrical charge.

Ionosphere

Another term for the thermosphere, used due to the abundance of ions.

Northern Lights

Polar auroras created by ions formed in the thermosphere from collisions of charged particles from the Sun.

CO2 Dissolution

Once the world ocean existed, CO2 from the atmosphere could dissolve in its waters.

Calcium Carbonate Formation

Dissolved CO2 reacted with Ca to form solid calcium carbonate (CaCO3), which precipitated and accumulated on the seafloor.

Seafloor Accumulation

Many organisms incorporate CaCO3 into their shells and skeletons, which then accumulate on the seafloor.

Geosphere

The geosphere is the world's largest carbon reservoir and a global sink for CO2.

Third Atmosphere

Today's atmosphere is called Earth's third atmosphere.

Transformation to Third Atmosphere

Big changes were needed to transform Earth's second atmosphere to make the third atmosphere.

Hydrosphere Excess

Excess H2O went to the hydrosphere—mostly in oceans, but also as rivers, lakes, and streams.

Earth's oceans

formed from water that precipitated from the second atmosphere

Nitrogen

degassed significantly to provide nearly 80% of our air as we now know it

Atmosphere's free oxygen

tied to changes in the biosphere

Photosynthesis

process by which organisms use energy from sunlight to convert CO2 and H2O into food and oxygen

Banded iron formations

formed when some of the oxygen reacted with iron and sulfur that readily react with the oxygen

Oxygen concentration

of the atmosphere increased as photosynthetic organisms generated O2

Ozone

Molecule with 3 oxygen atoms (O3)

Temperature changes in the stratosphere

caused by the interaction of incoming solar radiation and oxygen

Ozone Layer

part of the stratosphere where natural ozone is concentrated

Ozone formation

occurs slowly in the stratosphere and can be destroyed by reactions with sunlight and other atmosphere components

Ozone concentration

is higher in the lower stratosphere where it is not destroyed as rapidly

Hydrosphere

consists of all water in oceans, on land in streams and lakes, in glaciers and other accumulations of ice, in the atmosphere and underground

Water Planet

Water covers 71% of Earth's surface

Earth's water phases

exists in all three phases —solid (ice), liquid, and gas (water vapor)

World's oceans

are the largest reservoir in the hydrosphere, containing 97% of Earth's water

Freshwater

only 2.8% of Earth's water; only a small amount of that water is readily available for humans

Freshwater distribution

found in lakes, streams, rivers, underground, and in the atmosphere

Glacier

a large mass of ice formed at least in part on land by the compaction of snow

Ice sheet

an area where glaciers coalesce and cover more than 50,000 square kilometers

Glacier formation

occurs if snow accumulation exceeds melting of snow

Mountain glaciers

vary from small patches to large rivers of ice that slowly flow downslope

Modern world ice coverage

ice covers about 10% of Earth's land area

World ocean influence

is a major influence on global climate due to water's great specific heat capacity compared to air

Upper ocean layer

is warmed by the sun and mixed by the waves and currents created by surface winds, about 200 meters thick

Lower ocean layer

at depths below about 1000 meters, solar radiation has little effect, and water temps are low, commonly in the 0°C to 4°C (32°F to 39°F) range

Water motion in the ocean

is caused by salinity and temperature differences that change the water's density

Water Cycle

interacts with other Earth systems and transfers a prized resource among its reservoirs (oceans, atmosphere, on and under land)

Atmosphere over oceans

is a key part of the water cycle; ~86% of its water vapor obtained through evaporation from seas

Water storage

is temporary as it cycles back to the atmosphere through respiration and transpiration

Water Cycle processes

involve energy and matter transfer between atmosphere, biosphere, and geosphere

Precipitation

occurs when air rises, cools, and water vapor turns into tiny droplets to form clouds

Precipitation types

includes rain, snow, or ice (hail) that transfers water to the land

Reservoirs on land

include ice, surface water, and groundwater

Rivers and streams

carry water back to the oceans; groundwater migrates back to the oceans

Earth's position in the solar system

is perfect for the three physical systems, permitting a wide range of life forms to be sustained

Globally defined physical systems

include the Geosphere, Hydrosphere, and Atmosphere

Physical systems interaction

provides niches for all of the biosphere, including humans