APES Unit 4

What is ENSO (El Niño-Southern Oscillation)?

A naturally occurring climate cycle involving periodic warming (El Niño) and cooling (La Niña) of central and eastern tropical Pacific ocean surface waters coupled with shifts in atmospheric pressure and thermocline depth It alters global weather storm tracks and fisheries worldwide.

What is plate tectonics?

The theory that Earth’s outer shell is divided into several large moving plates that glide over the mantle It drives geologic activity (earthquakes volcanoes mountain building island arcs and hot spots) and shapes global geography and ocean basins over millions of years.

What is soil formation?

The continuous process of weathering of parent material (rock) combined with the accumulation and decomposition of organic matter over time influenced by climate organisms relief and time It provides the foundation for terrestrial ecosystems and agriculture.

What is the urban heat island effect?

A phenomenon where urbanized areas experience significantly higher temperatures than surrounding rural areas due to dark impervious surfaces (asphalt/concrete) sparse vegetation and anthropogenic heat from buildings and vehicles.

What are global wind patterns?

Large-scale atmospheric circulation cells driven by uneven solar heating and insolation differences across latitudes combined with the Earth's rotation (Coriolis effect) They redistribute heat and moisture globally driving climate and ocean currents.

What are divergent boundaries?

Plates move apart.

Where are divergent boundaries located?

Mid-Atlantic Ridge and East African Rift.

What landforms are created at divergent boundaries?

Mid-ocean ridges rift valleys new crust and volcanoes.

What are convergent boundaries?

Plates collide.

Where are convergent boundaries located?

Himalayas Andes Mountains and Mariana Trench.

What landforms are created at convergent boundaries?

Fold mountains (continental-continental) and deep ocean trenches and volcanic island arcs or coastal mountain ranges (oceanic-continental or oceanic-oceanic).

What are transform boundaries?

Plates slide past each other horizontally.

Where are transform boundaries located?

San Andreas Fault.

What landforms or features are associated with transform boundaries?

Earthquakes and fault lines (no major mountains or trenches created/destroyed).

What are hot spots?

Volcanic regions fed by underlying mantle plumes that are abnormally hot compared to the surrounding mantle occurring independently of plate boundaries (e.g. Hawaiian Islands).

What are island arcs?

Curving chains of volcanic islands created at oceanic-oceanic convergent boundaries where subduction occurs.

What is a fault line or fault plane?

The fracture surface along which tectonic movement and slippage take place.

What is the hypocenter or focus of an earthquake?

The exact underground location where an earthquake rupture begins.

What is an earthquake epicenter?

The point on Earth's surface directly above the hypocenter.

How do tsunami waves form?

Submarine earthquakes tectonic displacement or landslides at convergent boundaries that displace massive volumes of water generating powerful seismic sea waves.

What occurs at subduction zones?

One tectonic plate (denser usually oceanic crust) is pushed beneath another plate (less dense continental or younger oceanic crust) and descends into the mantle where it melts This creates deep ocean trenches powerful earthquakes and volcanic arcs.

Which plates are involved in subduction?

Oceanic-Continental convergence or Oceanic-Oceanic convergence (Continental-continental plates are too buoyant to subduct).

How does pH affect soil?

Influences nutrient availability and microbial activity Extreme acidity (low pH) or alkalinity (high pH) can make essential nutrients unavailable or release toxic heavy metals like aluminum.

How does soil compaction affect soil and plant health?

Decreases pore space reduces soil aeration lowers water infiltration and inhibits root growth leading to increased runoff and erosion.

How does drought affect soil?

Reduces soil moisture shrinks clay particles kills beneficial soil microbes and can lead to wind erosion and soil cracking.

What is the O horizon in soil?

Freshly decomposed organic matter humus and leaf litter Rich in nutrients.

What is the A horizon or topsoil?

Mineral mixed with organic humus Dark color high biological activity (worms bacteria) crucial for plant growth.

What is the E horizon in soil?

Located between the A and B horizons which is a zone of intense leaching where iron aluminum and organic acids are washed downward into lower layers.

What is the B horizon or subsoil?

Accumulation of leached minerals (iron aluminum clay) from upper layers Lighter in color with less organic matter.

What is the C horizon in soil?

Partially weathered bedrock and broken-down rock fragments Representing the least weathered layer.

What is splash erosion?

Initial stage where raindrops strike bare soil dislodging particles.

What is sheet erosion?

Surface runoff removes a thin uniform layer of soil across an area.

What is rill erosion?

Small distinct channels or rivulets carved by running water.

What is gully erosion?

Rills deepen and widen into large steep-sided ditches.

What is stream bank erosion?

Flowing water continuously wears away the banks of streams or rivers.

What do physical soil tests measure?

Measure soil texture particle size distribution porosity permeability structure and water-holding capacity.

What do chemical soil tests measure?

Measure soil pH salinity cation exchange capacity (CEC) and nutrient levels (N P K).

What do biological soil tests assess?

Assess soil organism biodiversity earthworm populations microbial respiration and organic matter decomposition.

What is soil porosity?

The volume of open pore spaces between soil particles.

What is soil permeability?

The rate at which water and air pass through soil.

What is water-holding capacity in soil?

The total amount of water a soil texture can retain against gravity.

What is soil fertility?

The capacity of soil to supply vital nutrients for plant growth.

What are the characteristics of sand in soil?

Highest porosity highest permeability and lowest water-holding capacity.

What are the characteristics of silt in soil?

Moderate porosity moderate permeability and moderate water-holding capacity.

What are the characteristics of clay in soil?

Lowest permeability highest water-holding capacity and very small pore spaces.

What soil texture corresponds to 60 percent sand 30 percent silt and 10 percent clay?

Sandy Loam

What soil texture corresponds to 20 percent sand 10 percent silt and 70 percent clay?

Clay

What is a watershed?

An area of land where all precipitation drains into a common body of water such as a river lake or bay.

How does slope and topography affect a watershed?

Steeper slopes increase runoff velocity erosion potential and drainage rates.

How do area and shape affect a watershed?

Dictates the volume of collected water and response time for runoff.

What are watershed divides?

High-elevation ridges or boundaries separating adjacent drainage basins.

What are the sources and impacts of watershed pollution?

Point sources (factories sewage pipes) and non-point sources (agricultural runoff urban oil/fertilizer runoff) introduce excess nutrients (causing eutrophication) heavy metals and pathogens that degrade water quality and aquatic ecosystems.

What are strategies to reduce soil erosion in watersheds?

Contour plowing terracing strip cropping no-till agriculture and planting cover crops or riparian buffer strips.

What are methods to reduce pollution runoff?

Rain gardens permeable pavement capturing stormwater in retention ponds reducing chemical fertilizer use and maintaining forested riparian buffers along streams.

What is the troposphere?

Temperature decreases with altitude because it is heated from the Earth's surface (Weather occurs here).

What is the stratosphere?

Temperature increases with altitude due to the absorption of UV radiation by the ozone layer.

What is the mesosphere?

Temperature decreases with altitude due to a lack of gas molecules to absorb solar radiation making it the coldest layer.

What is the thermosphere?

Temperature increases with altitude due to the direct absorption of high-energy X-ray and UV radiation from the sun.

What is the relative concentration of nitrogen in the atmosphere?

~78% (Highest)

What is the relative concentration of oxygen in the atmosphere?

~21%

What is the relative concentration of argon in the atmosphere?

~0.93%

What is the relative concentration of carbon dioxide and trace gases in the atmosphere?

~0.04% (Lowest major component)

What is insolation?

The amount of solar radiation reaching a given area of Earth's surface which varies significantly by latitude due to the angle of sunlight.

What causes the seasons?

Caused by the Earth's 23.5° axial tilt as it revolves around the sun changing the angle of solar insolation and day length throughout the year.

What occurs during the summer solstice on June 21?

Northern Hemisphere tilted toward the sun representing the longest day in the Northern Hemisphere and winter in the Southern Hemisphere.

What occurs during the winter solstice on December 21?

Northern Hemisphere tilted away from the sun representing the shortest day in the Northern Hemisphere and summer in the Southern Hemisphere.

What occurs during the spring and fall equinoxes?

Earth's axis is side-on to the sun resulting in equal day and night worldwide.

What causes day length fluctuation throughout the year?

The tilt causes the hemisphere tilted toward the sun to experience longer daylight hours while the opposite hemisphere experiences shorter daylight hours.

What are atmospheric convection cells?

Warm air is less dense so it rises (low pressure) As it rises it cools moisture condenses (rain) and the dry air becomes denser and sinks (high pressure) forming convection loops like Hadley Ferrel and Polar cells.

Where and why do rainforests occur?

Occur near the equator where warm moist air rises (low pressure) and drops heavy precipitation.

Where and why do deserts occur?

Occur near 30° latitude where dry air descends (high pressure) creating arid conditions.

How do surface winds relate to air pressure?

Surface air always moves from High pressure to Low pressure.

What is the Coriolis effect?

The apparent deflection of moving air and water due to Earth's rotation where it is deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

Where are the trade winds or easterlies located?

Wind direction found from 0° to 30° latitude.

Where are the westerlies located?

Wind direction found from 30° to 60° latitude.

What is the rain shadow effect?

Moist air blowing inland from the ocean hits a mountain range rises cools and drops all its precipitation on the windward side while descending the leeward side dry to create an arid rain shadow.

What is lake effect snow?

Cold dry arctic air moves over a relatively warm unfrozen lake picking up moisture and heat before hitting land on the leeward side where it cools and dumps heavy snow.

What are normal weather conditions during an ENSO cycle?

Trade winds push warm surface water west maintaining a deep thermocline in the west and a shallow thermocline in the east that drives strong coastal upwelling of cold nutrient-rich water off South America.

What occurs during an El Niño event?

Trade winds weaken or reverse allowing warm water to slosh eastward toward the Americas flattening the thermocline and suppressing upwelling off South America with effects including warmer/drier winters in parts of North America heavy rainfall/flooding in the Americas and drought in Australia/Asia.

What occurs during a La Niña event?

Trade winds strengthen pushing warm water farther west deepening the western thermocline and intensifying cold water upwelling in the eastern Pacific with effects including colder winters in northern North America drought in the southern US and heavy monsoon rains in Southeast Asia and Australia.

What causes the urban heat island effect?

Dark heat-absorbing impervious surfaces (asphalt/roofs) lack of evapotranspiration from vegetation and waste heat from AC units and cars.

What are solutions to the urban heat island effect?

Installing green roofs (vegetation on rooftops) and planting urban trees/shading to increase albedo and cooling via transpiration.

What is an independent variable in an experiment?

What the researcher intentionally changes or manipulates on the x-axis.

What is a dependent variable in an experiment?

What is measured or represents the result on the y-axis.

What is a control group in an experiment?

The baseline group left unmanipulated for comparison.

What is primary succession?

Starts on bare rock with no soil such as after a volcanic eruption or retreating glacier.

What is secondary succession?

Starts in an area where an existing ecosystem was disturbed or destroyed but soil remains such as after a forest fire or clear-cutting.

What is the role of moss and lichens in primary succession?

Act as pioneer species in primary succession by secreting acids that weather bare rock into soil and contributing organic matter when they die.

What is the largest carbon reservoir?

Sedimentary rocks like limestone and oceans.

What is the largest hydrologic reservoir?

Oceans.

What is the largest nitrogen reservoir?

Atmosphere.

What is the largest phosphorus reservoir?

Sedimentary rock or lithosphere.

Which nutrient cycle lacks an atmospheric component?

Phosphorus cycle because phosphorus never enters the atmosphere as a gas.

What is the impact of adding trees to an environment?

Trees increase transpiration intercept rainfall to reduce immediate runoff and have roots that enhance infiltration groundwater recharge and soil stabilization.

What is the most diverse terrestrial biome?

Tropical Rainforest.

What is the most diverse marine biome?

Coral Reef.

What is commensalism?

One organism benefits while the other is unaffected (e.g. barnacles on a whale).

What is mutualism?

Both organisms benefit (e.g. bees and flowers or coral and zooxanthellae).

What is predation?

One organism hunts and kills another for food (e.g. wolf and deer).

What is parasitism?

One organism lives on or in a host and harms it without immediately killing it (e.g. tapeworms or ticks).