APES Unit 4

earth’s structure

• 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: thin, brittle layer of rock floating on top of mantle (broken up into tectonic plates)

  • 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

divergent plate boundary

• plates move away from each other

• rising magma plume from mantle forces plates apart

  • forms: mid-oceanic ridges, volcanoes, seafloor spreading, and rift valleys (on land)

convergent plate boundary

• plates move towards each other

• leads to subduction (one plate being forced another)

  • forms: mountains, island arcs, and volcanoes

transform fault plate boundary

• plates slide sideways past each other (earthquakes)

  • forms: faults (fracture in rock)

mantle convection currents

• 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”

• magma cools and solidifies into new lithosphere at spreading zone

• spreading magma forces oceanic plate under continental plate

  • sinking oceanic plate melts back into magma

  • new magma is forced up, creating narrow, coastal mountains (e.g Andes) and volcanoes on land

convergent boundaries

• 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 continental plate and melts back into magma

  • forces magma up to lithosphere surface

  • coastal mountains (andes), volcanoes on land, trenches, tsunamis

• contential- continental: surface crust from both plates “buckles” upward (mountains)

  • Ex: Himalayas

transform fault boundary

• plates sliding sideways past each other; can create a fault (fracture in rock surface)

  • earthquakes occur when rough edges of plates get stuck on each other

  • pressure builds as plates keep sliding, but edges stay stuck

  • when stress overcomes the locked fault, plates suddenly release slide past each other and release energy that shakes the lithosphere

Tectonic map can predict..

• ring of fire: pattern of volcanoes and earthquake zones all around pacific plate

  • offshore island arcs (Japan)

    • from convergent boundaries

• transform faults: likely location of earthquakes

• hotspots: areas of especially hot magma rising up to lithosphere

  • mid-ocean islands (Iceland, Hawaii)

Soil

mix of geologic (rock) and organic (living) components

• sand, silt, clay

• humus: main organic part of soil (broken down biomass like leaves, dead animals, waste, etc.)

• nutrients: ammonium, phosphates, nitrates

• water and air

• living organisms

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)

subduction

one plate being forced beneath another, leads to

• mountains, island arcs, earthquakes, and volcanoes

  • convergent plate boundary

Roles of Soil

• Breaks down organic material and recycles nutrients

  • home to decomposers that break down dead organic matter and return nutrients to the soil

• medium for plant growth

  • anchors roots of plants and provides water, shelter, nutrients (N, P, K, Mg) for growth

• habitat for a variety of organisms

  • provides habitat for organisms like earthworms fungi, bacteria, moles, etc

• filters water

  • filters rainwater+ runoff by trapping pollutants in pore spaces +plant roots, clean water enters groundwater+aquifers

Soil Formation

TOP:

• breakdown of organic matter adds humus to the soil

  • soil nutrient level, depth of soil

• erosion deposits soil particles from other areas, adding to soil

BELOW:

• weathering of parent material produces smaller, and smaller fragments that make up geological/ inorganic part of soil

  • sand, silt, clay

  • minerals

  things that effect soil formation:

• parent material: soil pH, nutrient content

• topography: steep slope= too much erosion; more level ground=deposition

• climate: higher temps=faster breakdown of organic matter; more precip.=more weathering, erosion+deposition

• organisms: soil organisms like bacteria, fungi, worms breakdown organic matter

Soil Horizons

O-Horizon: layer of organic matter (plant roots, dead leaves, animal waste, etc) on top of soil

• provides nutrients and limits H20 loss to evaporation

A-Horizon: aka topsoil; layer of humus (decomposed organic matter) and minerals from parent material

• has the most biological activity (earthworms, soil microbes) breaking down organic matter to release nutrients

B-Horizon: aka subsoil; lighter layer below topsoil, mostly made of minerals with little to no organic matter

• contains some nutrients

C-Horizon: least weathered soil that is closest to parent material, sometimes called bedrock

Soil Degradation

The loss of the ability of soil to support plant growth

• loss of topsoil: tiling (turning soil for agriculture) and loss of vegetation disturb soil and make it more easily eroded by wind and rain

  • loss of topsoil 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 easier

  • dry soil supports less plant growth, less root structure, leading to more erosion

• nutrient depletion: repeatedly growing crops on the same soil removes key nutrients (N, P, K, Na, Mg) over time

  • reduces ability to grow future crops

Soil texture

the % of sand, silt, and clay in a soil

• always adds up to 100% ex: 40-40-20

• since sand is bigger, it has bigger pores (empty spaces between particles)

  • allows air+water to enter sandy soil easily

  • clay has the smallest pores, so it’s harder for air + water to enter clay-heavy soils

porosity

the amount of pore space a soil has

• more sand in soil=more porous/higher porosity (easier for water+air to enter)

• more clay in a soil=less porous/ less porosity (harder for water+air to enter)

Porosity, Permeability, and H20 Holding Capacity

• porosity: the pore space within a oil (more sand, more porous)

• permeability: how easily water drains through a soil

• more porous/ higher porosity=more permeability

• h20 holding capacity: how well water is retained, or held by soil

  • more porous/ permeable=lower H20 holding capacity

soil that is too sandy drains water too quickly for roots and dries out, clay-heavy soil doesn’t let H20 drain and waterlogs roots. Ideal soil is loam which balances porosity with h20 capacity. (40-40-20)

Factors that increase and decrease soil nutrients

• increase nutrients

  • N, P, K+,, MG2+, Ca+, Na+

• organic matter (releases nutrients)

• humus (holds and releases nutrients)

• decomposer activity (recycles nutrients)

• clay (negatively charge, binds with pos nutrients)

• bases (calcium carbonate-limestone)

• decrease nutrients

  • acids leach positively charged nutrients when excessive rain/ irrgation

  • excessive farming

  • topsoil erosion

factors that increase and decrease H20 holding cap

• increase holding cap

  • aerated soil, biological activity

  • compost/humus/organic matter

  • clay content

  • root structure,native plants with deep roots

• decrease holding cap

  • compacted soil (machines, cows)

  • topsoil erosion

  • sand

  • root loss

Gasses of Earth’s Atmosphere

• Nitrogen-78%

  • in the form of N2 gas which is unusable to plants without being fixed

• Oxygen-21%

  • produced by photosynthesis in plants and need for human and animal resp

• Argon- 0.93% inert, noble gas

• water vapor-0-4%

  • varies by region and conditions; acts as a temporary GHG but not that concerning

  • quickly cycles through atmosphere

• CO2- 0.04%

  • most important GHG; leads to global warming

  • removed from atmosphere by photosynthesis

Characteristics of the Layers of the Atmosphere

• exosphere: outermost layer where atmosphere merges with space

• thermosphere: therm=hottest layer

  • absorbs harmful X-rays and UV radiation

  • charged gas molecules glow udner intense solar radiation producing northern lights (aurora borealis)

• mesosphere: “m” for middle

  • even less dense

• stratosphere: “s” for second

  • thickest O3 layer is found here; absorbs UV- B and C rays which can mutate DNA of animals (cancer)

• trophosphere:

  • weather occurs here

  • most dense due to pressure of other layers above it

  • most of atmosphere’s gas molecules are found here

  • Ozone in the trophosphere is harmful to humans (resp irritant). damages plant stomata, and forms smog

Temperature Gradient

layers of the atmosphere are based on where temperature gradients change with distance from earth’s surface

• thermosphere: temperature increases due to absorption of highly energetic solar radiation

  • hottest place on earth

• mesosphere: temperature decreases because density decreases, leaving fewer molecules to absorb sun

  • coldest place on earth

• stratosphere: temperature increases because top layer is warmed by UV rays (like a top layer of a pool)

• trophosphere: temperature decreases as air gets further from warmth of earth’s surface

Air Properties

• warm air rises

• warm air holds more moisture than cold

• rising air expands and cools

• cool air can’t hold as much H20 vapor

  • condenses→rain

• after cooling and expanding, air sinks

Hadley Cell

1. More direct sunlight at equator warms air

2. warm air rises, cools, and expands, H20 vapor condenses into rain

3. air continues to rise, cool, and expand

4. cooling, expanding air spreads out

5. cool, dry air sinks back down to earth @30degrees N and S

   1. deserts form here due to lack of moisture in air

• air moves from high to low pressure so air along earth’s surface flows from 30degrees back to the equator (0 degrees)

Coriolis Effect

• deflection of objects traveling through atmosphere due to the spin of the earth

• air at 30 degrees moves back to low pressure of equator

• wind between 0-30 degrees moves from East to West

  • b/c earth is spinning west to east

    winds between 30-60 degrees move west → east

    • bc earth spins faster at 30 than 60 degrees

Global wind patterns

1. Air moves out from 30 degrees to 0 degrees and 60 degrees due to high pressure at 30 degrees and low pressure at 0 and 60

   1. air rising at equator=low pressure, air sinking down at 30 degrees= high pressure

2. 0-30 degree winds blow east → west (eastern trade)

   1. drives ocean current clockwise in Northern hemisphere and counterclockwise in Southern hemisphere

3. 30-60 degree wins blow W→ East (westerlies)

   1. drives weather patterns of North America

latitude

the measurement of distance north or south of the equator, expressed in degrees.

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, and slope play a large role in how watersheds drain

  • more vegetation=mroe infiltration and groundwater recharge

  • greater slope=faster velocity of runoff and more soil erosion

  • soil permeability→ determines runoff vs. infiltration rates

human activities in a watershed impact water quality (agriculture, cleacutting, urbanization, dams, mining)

Chesapeake Bay Watershed

6 state region that drains into a series of streams/ rivers and eventually into Chesapeake Bay

• mix of fresh and salt water + nutrients in sediment make estuary habitats like the salt marshes in the bay highly productive

provides many ecosystem services

• tourism revenue—hotels, restaurants, permits

• water filtration (grass roots trap pollutants)

• habitats for food sources (fish and crabs)

• storm protection (absorbing and buffering floods)

human impacts on Chesapeake Bay

Nutrient pollution (N and P) leads to eutrophication in the Bay

• algae bloom due to increase of nutrients → decreased sunlight → plants below surface die → bacteria uses oxygen to decompose → hypoxia and dead zones (positive feedback loop)

  • Major N/P sources:

    • discharge from sewage treatment plants (in human waste)

    • animal waste from CAFOS

    • synthetic fertilizer from agricultural fields and lawns

  • other pollutants:

    • endocrine disruptors (from sewage treatment)

    • sediment pollution (deforestation, urbanization, tilling agricultural fields)

      • increases turbity (reduced photosynthesis) and covers over rocky streambed habitats

Solutions

• cover crops: using plants in between the main crops being harvested to keep sediments and fertilizers from running into bodies of water

• animal manure management: manure lagoons with better lining, draining more frequently, etc.

• riparian buffers: areas alongside a body of water where you plant vegetation to add a sponge/ filter before water goes into bodies of water

• septic tank upgrades: tank that collects waste→ optimize drain, prevent overflowing and contaminating nearby waters, biological waste removal

insolation

the amount of solar radiation (energy from sun’s rays) reaching an area

• measured in Watts/ m²

solar intensity and latitude

• solar intensity of insolation (W/m²) depends on:

  a. angle: how directly rays strike earth’s surface

  b. the amount of atmosphere sun’s rays pass through equator is more horizontal

• equator=higher insolation than higher latitudes

• higher latitudes=less insolation due to atmospheric distance needed to be breached and oblique angle (not right)

solar intensity and seasons

• orbit of earth around the sun and 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 and December solstices: N or S hemisphere is maximally tileted toward sun (summer/winter) → longest day of year (June) shortest day (December)

  • March and September equinox: N and S hemispheres equally facing sun (spring and fall)

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)

  • absorb more heat

urban heat island

urban areas are hotter than surrounding rural area due to low albedo of blacktop

climate and geography

climate is largely determined by insolation (latitude → angle of insolation and atmosphere)

• higher latitudes receive less insolation: cooler, less precipitation (esp 30 degrees)

• equator receives most intense insolation: higher temp, air rises, high precip

geography also plays a role

• mountains: disrupt wind and produce rain shadow effect

• oceans: moderate temperature and add moisture to the air

rain shadow effect

• warm, moist air from the ocean hits the "windward” side of the mountain, rises, cools (condensing H20 vapor and causing rain) → lush, green vegetation

• dry air descends down “leeward” side of mountain, warming as it sinks

  • leads to arid (dry) desert conditions

Global Ocean Surface Currents

gyers: large ocean circulation patterns due to global wind

• clockwise in the northern hemisphere, counterclockwise in southern

  • east → west trade winds between 0-30 degrees push equator current E→ W

  • Westerlies between 30-60 push mid latitude currents W→E

upwelling zones

areas of ocean where winds blow warm surface water away from land mass and replace it with colder, deeper water

• brings 02 and nutrients to surface → productive fishing

thermohaline circulation

connects all of the world’s oceans, mixing salt, nutrients, and temperature throughout

• warm water from Gulfof Mexico moves towards North Pole

• cools and evaporates as it moves towards poles

• saltier and cooler water at poles, is more dense, making it sink

• spreads along ocean floor

• rises back up into shallow warm ocean current at upwelling zones

El Nino Southern Oscillation (ENSO)

pattern of shifting atmospheric pressure and ocean currents in the pacific ocean between South America and Australia/ Southeast Asia

• oscillates, or shifts regularly from El nino (warmer, rannier) to La Nina (cooler, drier) conditions along coast of South America

El Nino Event

• trade winds weaken, then reverse (W→E)

• warm equator currents bring heat and precipitation to Americas (warmer winter)

• increased precip and flooding in Americas (esp west coast)

• suppressed upwelling off SA coast (damaging fisheries)

• cooler, drier conditions in Australia and SE Asia (weakened monsoon activity)

• High pressure in west pacific (Aust, SEA)

• low pressure in east pacific (SA)

La Nina conditions

• stronger than normal trade winds (W,←E)

• increasing upwelling off SA coast brings cooler than normal conditions

  • better fisheries

  • worst tornado activity in the US and hurricane activity in the Atlantic

• warmer and higher precip in Aust and SEAS