Unit 4 - Earth Systems & Resources

4.1 Plate Tectonics

%%layers of the Earth%%: crust (lithosphere), upper mantle (asthenosphere), and mesosphere (lower mantle)
%%plates%%: sit on the asthenosphere or upper mantle; move in all directions; can be continental or oceanic & have multiple boundary types
%%plate boundaries%%: separates layers of the Earth; varies globally
- ^^convergent plate boundary^^: plates push toward each other
- causes volcanoes, releasing magma & earthquakes
- ^^divergent plate boundary^^: plates push away from each other
- volcano ridges or mountains
- can cause earthquakes
- ^^transform (strike-slip) plate boundary^^: plates slide off each other
- no ridges or volcanoes; shallow frequent earthquakes
%%earthquake formation%%: occur at fault lines or plate boundaries → builds up stress/energy → release of energy causes the earth to shake
geologic events help to ==identify plates== by creating a pattern of similar area
- effects of geologic events: earthquakes, volcanic eruption, and tsunamis
^^tsunamis^^: long sea wave
- can be caused by underwater landslides and earthquakes
- can cause contaminated water, uplifting trees, and damage to life on land

4.2 Soil Formation and Erosion

%%soil%%: forms from the weathering (mechanical process of breaking down rocks of parent materials (broken down rocks)
- ^^type of parent material^^: influences soil chemistry
- ^^climate:^^ avg temperate, moisture, weathering rate, nutrients, wind redistribution
- ^^topography^^: affects erosion (slope of the land)
- ^^biological factors^^: microorganism, plant & animal use
- ^^time^^: neverending, continuous
%%soil profile%%: combination of soil layers from various types of rock & organism matter
- ^^surface horizon^^: basic rock material + human/organic material
- ^^subsoil^^: more basic material than organic matter
- ^^substrata^^: most parent material
- ^^bedrock^^: granite, basalt, limestone, sandstone, etc.
%%soil erosion%%: weathering of soil
- caused by water, wind, gravity, human factors → water contamination
- ^^human impact on soil erosion^^: deforestation (lack of roots on soil) overgrazing (overeating leads to overexposure of top soil layer → vulnerable to wind & rain)
- ^^pesticides/fertilizers^^: changes soil chemistry, kills beneficial microorganisms
- ^^tillage^^: breaking up soil → preventing it from organic matter accumulation for nutrition
- ^^sheet erosion^^: surface layer is removed by water; prevented by maintaining plant cover
- ^^rill erosion^^: small channels of water flow in soil → strig cropping or contour plowing)
- ^^gully erosion^^: wide cuts in soil from rill erosion → diverting water to other streams and flows

4.3 Soil Composition & Properties

soil = sand + silt + clay
- ^^sand^^: 2 mm to 0.05 mm (allows water to pass through)(takes 1 hour)
- ^^silt^^: 0.05 mm to 0.002 mm
- ^^clay^^: < 0.002 mm (blocks water from passing through)(takes 100 years)
soil composition is determined by the percentage of each soil particle → influences soil type (@@soil triangle@@)
%%soil test%%: the process of assessing soil content and attributes
- ^^chemical^^: nitrogen, phosphorous, pH/acidity
- fertilizers = increase in nutrients (nitrogen, phosphorus, potassium)
- tend to have 7.5 pH (basic)
- rainfall → increases acidity
- ^^physical^^: soil composition & water holding capacity
- amount of sand, silt, and clay → percolation/infiltration
- percolation: water → ground
- infiltration: ions/chemicals → ground (same process as percolation)
- ^^biological^^: microorganisms
- contains bacteria, archaea, fungi, earthworms, burrowing animals, etc.

4.4 Earth’s Atmosphere

atmosphere = 78% nitrogen + 21% oxygen + 1% trace gases (argon, co2, methane, krypton, hydrogen, water, etc.)
- exosphere: 600-10,00km; continues to rise until outer space
- thermosphere: 85-600km; rise in temperature due to UV rays
- mesosphere: 50-85km; drop in temperature as air thins out
- stratosphere: 20-50km; rise in temperature from ozone formation
- troposphere: 0-6-20km; air is most dense

4.5 Global Wind Patterns

air circulates as earth rotates
convection: changes in density temperature
coriolis effect: earth’s rotation deflects the wind (hot air in moving but also turning at the same time)
- leads to routine weather patterns in both hemispheres

4.6 Watersheds

watershed: highest point/divide in a river
- tributary: smaller streams meet larger river
- delta: river meets larger body of water
- aquifer: groundwater under the river
source zone: where the water in the river comes from
- ex. ice cap
transition zone: after the headwater; clear cold full oxygenated
floodplain: more sedimentation → less oxygenated filled with more nutrients
rainwater → runs downhill to river or percolates through the soil to groundwater

4.7 Solar Radiation & Earth’s Seasons

primary energy source: solar radiation (constant)
insolation: incoming solar energy
- = solar radiation/area
- surface most perpendicular to the sun (equator) = highest insolation
- smaller angle = larger area of solar radiation spread = smaller insolation value
- areas near the pole = lower levels of insolation
- amount of energy is determined by latitude and season
northern hemisphere seasons:
- winter solstice: december 21-22; shortest day of the year, polar night
- autumnal equinox: september 22-23; day = night
- summer solstice: june 20-22; longest day of the year, midnight sun
- vernal equinox: march 20-21; day = night
southern hemisphere seasons:
- equinox days are the same (opposite of the northern hemisphere)
- longest day: december 20/21
- shortest day: june 20/21

4.8 Earth’s Geography & Climate

land - low specific + no mobility = quicker temperature increase
- specific heat = amount of energy needed to raise temperature per degree
water - high specific heat + high mobility = slower temperature increase
- coastal areas have more stable temperatures as a result of the intersection between water and land (stabilization of temperatures in both parts)
currents: bodies of water that flow around a piece of land
- warmer currents bring heat to land, raising temperatures in certain areas and providing humidity
- ex. brazil, england
- cooler currents bring coldness to land, dropping temperatures in certain areas and decreasing humidity
- ex. canada, angola
rainshadow effect: effect of coastal breezes from the ocean on mountains
windward side: part of the mountain next to the ocean
- air rises from the ocean currents → moisture rises → condensation, precipitation, vegetation → cools temperature on the mountain
leeward side: part of the mountain inland
- air becomes hot and dry → decreases moisture → arid and dry as it comes down the mountain
deserts form 30 degrees above and below the equator

4.9 El Niño & La Niña

enso: el nino southern oscillation
- series of weather events happens every 3-7 years in southern hemisphere (south america and australia)
normal wind patterns: wind goes from east to west → causes upwelling of phytoplankton (greater nutrient supply)
el nino: winds stop traveling or reverse; currents reverse → suppressing upwelling of life → decreased fishing commercialization
- begins in december to february until june to august
- countries surrounding australia experience dry weather → droughts, wildfires → habitat destruction
- countries surrounding south america experience warm & wet conditions → flooding, landslides, etc.
- pacific jet stream → warmer winters in canada & north america; wetter and colder in southern states; dry winters in midwest usa
- midwest → drier conditions
la nina: enhanced neutral conditions
- stronger currents, wind patterns, etc.
- warm current moves closer to australian shoreline
- greater upwelling in south america. (more phytoplankton)
normal ocean currents: warm current goes from south america to australia → cools down in australia → comes back to south america in oceanic life (upwelling)
- increased risk of floods and landslides
- cooler places get cooler and wetter weather, warmer places get warmer
- polar jet stream → colder winters, drier in midwest and south usa, warmer upper midwest, etc.