Unit 4 Flashcards
Core
Dense mass of nickel, iron, and radioactive elements that release massive amounts of heat
Mantle
bulk of Earth’s interior; three layers
Magma
(molten rock) layer that slowly circulates due to heat from core
Asthenosphere
semi-molten, flexible outer layer of mantle, beneath the lithosphere
Lithosphere
thin, brittle layer of rock floating on top of mantle (broken up into tectonic plates)
Crust
very outer layer of the lithosphere, Earth’s surface
Tectonic plates
Lithosphere floats atop the asthenosphere and can move and break into large pieces
Convergent
Two plates pushed toward each other
One of the plates will be pushed deep into the mantle
Subduction occurs → results in uplifting plates to form large mountain chains
Divergent
Two plates moving away from each other
Causes a gap that can be filled with magma → cools to form a new crust
Transform fault
Two plates slide from side to side relative to each other
Mountains formed by….
Mountains formed by magma from earth’s interiors
Magma heated by earth’s core rises towards lithosphere
Rising magma forces oceanic plates apart
Creates . . .
mid ocean ridges, volcanoes, spreading zones or “seafloor spreading”
Oceanic-Oceanic
one plate subducts underneath other
Forces magma up to lithosphere surface, forming mid ocean volcanoes
Island arcs
Off-shore trench
Oceanic-Continental
dense oceanic plate subducts beneath cont. Plate & melts back into magma
Forces magma up to lithosphere surface
Coastal Mountains (Andes), Volcanoes on land, trenches, tsunamis
Continental-Continental
surface crust from both plates “buckles” upward (mountains)
Ex: Himalayas
Ring of Fire
pattern of volcanoes & earthquake zones all around pacific plate
Offshore island arcs (Japan)
Transform faults
likely location of earthquakes
Hotspots
areas of especially hot magma rising up to lithosphere
Mid-ocean Islands (Iceland, Hawaii)
Humus
main organic part of soil (broken down biomass like leaves, dead animals, waste, etc.)
Weathering
Breakdown of rocks into smaller pieces
Physical (wind, rain, freezing/thawing of ice)
Biological (roots of trees crack rocks)
Chemical (acid rain, acids from moss/lichen)
Weathering of rocks = soil formation
Broken into smaller and smaller pieces
Carried away and deposited by erosion
Erosion
Transport of weathered rock fragments by wind and rain
Carried to new location and deposited (deposition)
Climate on soil formation
warmer = faster breakdown of org. matter;
more precip. = more weathering, erosion + deposition
Weathering of parent material(soil pH, nutrient content) produces
smaller, and smaller fragments that make up geological/inorganic part of soil
Sand, silt, clay
Minerals
O horizon
(organic horizon)
Uppermost horizon
Mostly made up of organic material including waste from organisms, bodies of decomposing organisms, live organisms
Dark crumbly material from the decomposition of organic material forms humus
Humus is rich in organic matter
A horizon
Made up of weathered rock and some organic material that has traveled down from the O layer
Called “topsoil”
Zone of leaching
Important role in plant growth
E horizon
(could occur beneath O or A horizon)
Leached of clay, minerals, and organic matter, leaving a concentration of sand and silt particles of quartz or other resistant materials – missing in some soils but often found in older soils and forest soils.
B horizon
Receives all minerals that are leached out of A horizon as well as organic materials that are washed down from the topsoil above
Zone of illuviation
Movement of dissolved material from higher soil layers to lower soil layers due to the downward movement of water (caused by gravity)
C horizon
Bottommost layer of soil
Composed of larger pieces of rock that have not undergone as much weathering
R horizon
“Bedrock”
Lies below all other layers of soil
Loss of Topsoil
tilling (turning soil for agriculture) + loss of
vegetation disturb soil and make it more easily eroded by wind and rain
Loss of top soil dries out soil, removes nutrients + soil organisms that recycle nutrients
Compaction
compression of soil by machines (tractors, bulldozers, etc.), grazing livestock, and humans reduces ability to hold moisture
Dry soil erodes more easily
Dry soil supports less plant growth, less root structure, leading to more erosion
Soil Degradation
The loss of the ability of soil to support plant growth
Nutrient Depletion
epeatedly growing crops on the same soil removes key nutrients (N, P, K, Na, Mg) over time
Reduces ability to grow future crops
Monoculture
Soil Pores
empty spaces between particles
Clay (less than 0.002 mm in diameter)
Easily adheres to each other
There is little room between particles for water → clay soil is compact
Silt (0.002 - 0.05 mm)
Medium
Sand (more than 0.05mm)
Too large to easily stick together
Sandy soils have larger pores → hold more water
Permeability
how easily water drains through a soil
Soil that is too sandy (too permeable) drains water too quickly for roots + dries out
Clay-heavy soil doesn’t let H2O drain to roots, or waterlogs (suffocating them)
Ideal soil for most plant growth is loam, which balances porosity or drainage, with H2O holding cap.
pH
low acidic (low pH) or basic/alkaline (high pH) soil is. More acidic soil = less nutrient availability
Gasses of Earth’s Atmosphere
Nitrogen 78%, Oxygen 21%, Argon, Water Vapor
Troposphere
Tropo = change (weather occurs here) - 0-16 km, most dense due to pressure of other layers above it
Most of atmosphere’s gas molecules and water vapor are found here
Ozone (O3) in the troposphere is harmful to humans (respiratory irritant) & damages plant stomata, and forms smog
Stratosphere: “S” for second - 16-60 km;
less dense due to less pressure from layers above
Thickest O3 layer is found here; absorbs UV-B & UV-C rays which can mutate DNA of animals (cancer)
Mesosphere
Meso = for middle; 60-80 km, even less dense
Thermosphere
Therm = hottest temp;
absorbs harmful X-rays & UV radiation
charged gas molecules glow under intense solar radiation producing northern lights (aurora borealis)
Exosphere
Outermost layer where atmosphere merges with space
Air properties
Warm air rises (less dense)
Warm air holds more moisture than cold
Rising air experiences less pressure, expands in volume
Expansion causes it to cool (adiabatic cooling)
Cool air can’t hold as much H2O vapor (condenses → rain)
Sinking air experiences more pressure, decreases in volume
Contraction causes it to warm (adiabatic warming)
Coriolis Effect
Appearance of deflection of objects traveling through atm. due to spin of earth
Objects above 30 N in NH deflected right
Objects below 30 S in SH deflected left
Trade winds push objects between equator and 30 N and 30 S to left due to trade winds
Hadley Cell
Convection cell accounts for land and sea breezes, on global scale, these are hadley cells
Large hadley cell starts its cycle over the equator → warm moist air evaporates and rises into the atmosphere (precipitation in the region near the equator is one cause of abundant equatorial rainforests) → cool dry air descends about 30 degrees North and South of the equator (forming belts of deserts seen around the earth at those latitudes)
Watersheds
All of the land that drains into a specific body of water (river, lake, bay, etc.)
Determined by slope; ridges of land divide watersheds (diff. runoff directions)
Vegetation, soil composition, slope play a large role in how watersheds drain
More vegetation = more infiltration & groundwater recharge
Greater slope = faster velocity of runoff & more soil erosion
Soil permeability determines runoff vs. infiltration rates
Chesapeake Bay Watershed
6 state region that drains into a series of streams/rivers & eventually into Chesapeake Bay
Mix of fresh & salt water + nutrients in sediment make estuary habitats like the salt marshes in the bay highly productive
Nutrient pollution (N & P) leads to eutrophication in the Bay
Algae bloom due to increase of N/P → decreased sunlight → plants below surface die → bacteria use up O2 for decomp. → hypoxia (low O2) & dead zones
Major N/P sources:
Discharge from sewage treatment plants (N/P levels from human waste)
Animal waste from CAFOs
Synthetic fertilizer from ag. fields & lawns
Effects of Clearcutting on Watersheds
Soil Erosion
Caused by loss of stabilizing root structure
Removes soil organic matter & nutrients from forest
Deposits sediments in local streams
Warms water & makes it more turbid (cloudy)
Increased soil & stream temp.
Loss of tree shade increases soil temperature
Soil has lower albedo than leaves of trees
Loss of tree shade along rivers & streams warms them
Erosion of sediments into rivers also warms them
Insolation
the amount of solar radiation reaching a given area
Solar intensity of insolation (W/m2) depends on:
Angle: how directly rays strike earth’s surface
The amount of atmosphere sun’s rays pass through
Equator =
higher insolation than higher latitudes
Orbit of earth around sun & tilt on axis changes angle of sun’s rays
This causes varying insolation, varying length of day, and seasons
Tilt of earth’s axis stays fixed during orbit
June & December Solstices: N or S hemisphere is maximally tilted toward sun (summer/winter)
March & Sept. Equinox: N & S hemispheres equally facing sun
March Equinox
Equator receives most direct insolation
N & S hemisphere get 12 hours of sunlight
Spring in N/Fall in S hemispheres
June Solstice
N tilted max. toward sun
Longest day in N (start of summer)
Shortest day in S (winter)
Autumn equinox
Equator receives most direct insolation
N & S hemisphere get 12 hours of sunlight
Fall in N/Spring in S hemispheres
December Solstice
S hem. tilted max. toward sun
Longest day in S (start of summer)
Shortest day in N (start of winter)
Albedo
the proportion of light that is reflected by a surface
Surfaces with higher albedo…
reflect more light, and absorb less (ice/snow)
Absorb less heat
Surfaces with low albedo ….
reflect less light, and absorb more (water, pavement, vegetation)
Absorb more heat
Surface temperature is affected by albedo
because
When sunlight is absorbed by a surface, it gives off infrared radiation (heat)
Areas w/lower albedo, absorb more sunlight light (heat)
Urban Heat Island
urban areas are hotter than surrounding rural area due to low albedo of blacktop
Thus, polar areas are…
Polar regions are colder due to higher albedo
Climate is largely determined by insolation (latitude → angle of insolation & atmosphere)
Higher latitudes receive less insolation: cooler, less precipitation (especially 30o)
Equator receives most intense insolation: higher temp, air rises, high precipitation
Geography also plays a role
Mountains: disrupt wind & produce rain shadow effect
Oceans: moderate temperature & add moisture to the air
Rain Shadows
Dry air descends down “leeward” side of mtn, warming as it sinks
Leads to arid (dry) desert conditions
Warm, moist air from ocean hits the “windward” side of the mtn, rises, cools (condensing H2O vapor & causing rain) → lush, green vegetation
Gyres
large ocean circ. patterns due to global wind
(clockwise in N hem, counterclockwise in S hem.)
Rain Shadow Ex
Eastern trade winds blow moist air from Atlantic across SA
Windward (E) side of Andes receives heavy rainfall
Leeward (W) side of Andes receives arid (dry) air
~30o latitude also contributes to lack of rain
high pressure, dry, descending air from Hadley cell
Eastern trade winds between 0-30o push eq. current W ← E
Westerlies between 30-60o push mid lat. currents W→ E
Upwelling Zones:
areas of ocean where winds blow warm surface water away from a land mass, drawing up colder, deeper water to replace it
Brings O2 & nutrients to surface → productive fishing
El Niño Southern Oscillation (ENSO)
pattern of shifting atmospheric pressure & ocean currents in the pacific ocean between South America and Australia/Southeast Asia
Oscillates, or shifts regularly from El Niño (warmer, rainier) to La Niña (cooler, drier) conditions along coast of South America
Process for Thermohaline Circulation
Warm water from Gulf of Mexico moves toward North Pole
Cools & evaporates as it moves toward poles
Saltier & colder water @ poles, is more dense, making it sink
Spreads along ocean floor
Rises back up into shallow warm ocean current @ upwelling zones
Thermohaline Circulation
Connects all of the world’s oceans, mixing salt, nutrients, and temperature throughout
Effects of El Niño
Suppressed upwelling & less productive fisheries in SA
Warmer winter in much of N America
Increased precip & flooding in Americas (W coast especially)
Drought in SE Asia & Australia
Decreased hurricane activity in Atlantic ocean
Weakened monsoon activity in India & SE Asia
La Niña
Stronger upwelling & better fisheries in SA than normal
Worse tornado activity in US & Hurricane activity in Atlantic
Cooler, drier weather in Americas
Rainier, warmer, increased monsoons in SE Asia
During a normal year…
Trade winds blow eq. water
W ← E
Cool H2O upwelled off coast of SA (cool temp + good fi$herie$)
Warm eq. current brings heat & precip. to Australia & SE Asia
High pressure in east pacific (SA)
Low pressure in west pacific (Australia & SE Asia)
During an el nino
Trade winds weaken, then reverse (W → E)
Warm eq. current brings heat & precip. to Americas (N & S)
Suppressed upwelling off SA coast (damaging fi$herie$)
Cooler, drier conditions in Australia & SE Asia
H pressure in west pacific (Australia & SE Asia)
L pressure in east pacific (SA)
During a la nina
Stronger than normal trade winds (W ← ← ← E)
Increased upwelling off SA coast brings cooler than normal conditions, extra good fi$herie$
Warmer & rainier than normal in Australia & SE Asia
