🌍 Unit 4: Earth Systems + Resources 🌍
Earth Systems and Resources
Unit 4
Earth's systems interact, resulting in a state of balance over time.
The majority of atmospheric processes are driven by energy input from the Sun
Plate Boundaries
Geological Changes and Events
Types of Plate Boundaries:
Convergent Boundaries:
Definition: Two tectonic plates moving towards each other.
Process: Subduction occurs where the denser tectonic plate moves under the less dense plate.
Plate Types: Can occur between two oceanic plates or between a continental and oceanic plate.
Geological Structures Formed:
Oceanic Plates: Likely to form island arcs, oceanic trenches, and volcanoes.
Oceanic and Continental Plates: Likely to form mountains and volcanoes.
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Divergent Boundaries:
Definition: Two tectonic plates moving apart from each other.
Effects: Creation of visible fault lines, rift valleys, seafloor spreading, volcanoes, and earthquakes.
Process: Seafloor spreading occurs where magma rises to fill the gap between the diverging plates, cooling in ocean water to form new rock.
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Transform Boundaries:
Definition: Tectonic plates slide past each other.
Outcome: Often leads to earthquakes due to the built-up friction and energy that is released suddenly.
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Analyzing Tectonic Maps
Importance: Geologists analyze tectonic plate maps to understand movements and potential natural disasters.
Example: The Ring of Fire in the Pacific Ocean helps explain the distribution of volcanoes and tectonic activity.
Application: Predicting optimal strategies for natural disaster prevention by understanding fault lines.
Soil Characteristics and Formation
Importance of Soil
Soil formation is crucial for plant growth and ecosystem balance. Protecting soil is essential for environmental health.
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Soil Formation Process
Parent Material: The starting material from which soil forms.
Weathering: Breakdown of parent material into smaller particles.
Deposition: Introduction of materials from other locations.
Vegetation Growth: Once a thin soil layer forms, small plants like moss begin to thrive, helping to further develop soil and introduce nutrients.
Soil Evolution: Interaction continues as more organisms populate the soil, continuously adding to its structure and nutrient content.
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Soil Horizons
O Horizon (Humus): Comprised of surface litter and decaying material.
A Horizon (Topsoil): Mixture of organic materials with minerals.
E Horizon (Eluviated): Zone of leaching where nutrients migrate to lower horizons.
B Horizon (Subsoil): Accumulation zone for minerals such as iron.
C Horizon (Parent Material): The broken-down base material used to form soil.
Bedrock: Solid rock beneath soil and parent material.
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Soil Erosion and Its Impacts
Causes: Soil can be washed away or eroded by wind and water, particularly when vegetation is absent.
Consequences: Erosion can lead to compromised water quality since soil filters water as it moves through.
Properties of Soil
Water-Holding Capacity
Definition: The amount of water that soil can absorb, influenced by particle size and organic matter.
Desirable Feature: Soils retain water in pores for agricultural purposes rather than allowing water to drain away.
Particle Size Effects:
Smaller particles correspond to higher water retention.
Larger particles facilitate drainage.
Organic matter increases water retention due to its absorptive qualities.
Loam: Soil type with balanced particle sizes (small, medium, large) offering optimal water retention, porosity, permeability, and fertility.
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Chemical Properties
Soil pH: Indicates acidity or basicity, influenced by environmental conditions. Acidic soil affects plant growth and can result from pollution.
Cation Exchange:
Definition: The process where soil particles attract and hold onto cations (positively charged ions).
Function: A high cation exchange capacity helps stabilize soil nutrient levels and pH, promoting overall soil health.
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Physical Properties
Aeration: Refers to the soil's ability to absorb nutrients, water, and oxygen.
Good aeration supports plant growth due to sufficient nutrient and water availability.
Soil Compaction: Describes the density of soil particles. High compaction reduces porosity and permeability, leading to less aeration.
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Biological Properties
Determined by organisms such as fungi and bacteria within the soil; these influence the soil composition and health.
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Soil Texture Triangle
A tool for determining soil types via the percentages of clay, silt, and sand, with specific angles marking the different particle lines.
Earth's Atmosphere
Composition
Primarily made of nitrogen (N2) and oxygen (O2).
Nitrogen Release: Through denitrification.
Oxygen Release: Through photosynthesis by plants.
Water Vapor (H2O): Concentrated around the equator compared to the poles.
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Additional Gases
Greenhouse Gases:
Methane (CH4), carbon dioxide (CO2), nitric oxide (N2O): Trap heat in the atmosphere.
Ozone (O3): Absorbs harmful UV radiation, protecting lower atmospheric layers.
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Atmospheric Layers
Troposphere:
Closest to Earth, extends up to ~10 km.
All weather occurs here.
Temperature decreases with altitude.
Stratosphere:
Ranges from 10 km to 50 km.
Composed mainly of ozone; temperature increases with altitude.
Mesosphere:
Extends from 50 km to 80 km.
Temperature decreases, can reach below -80 °C.
Thermosphere:
From ~80 km to 100 km; known as the ionosphere, temperature increases with altitude due to UV absorption.
Exosphere:
Extending from ~700 km to 10,000 km, merging with solar wind, very low density of molecules.
Home to many satellites.
Atmospheric Circulation
Wind Circulation
Driven by Earth's rotation and solar energy input.
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Circulated in three distinct cells:
Hadley Cell:
Closest to the equator, spans from equator to ~30° latitude.
Causes low-pressure at the equator, resulting in tropical thunderstorms and latent heat release.
Produces northeast and southeast trade winds affected by the Coriolis force.
Ferrel Cell:
Spans from 30° to 60° latitude; produces prevailing westerly winds.
Low-pressure at 60° latitude leads to cloud formation from converging air masses.
Polar Cell:
Circulates polar air from the poles towards 60° latitude, where it meets warmer air.
Predominantly contains easterly winds.
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Walker Circulation
An east-west atmosphere circulation over the eastern Pacific Ocean.
Influences precipitation patterns through trade winds and upwelling processes.
El Niño: Occurs when trade winds weaken, causing warmer waters and disruptions in ecosystems.
La Niña: Strengthened trade winds, resulting in cooler ocean temperatures and dry conditions in the southeastern US.
Effects of the Sun's Energy on Earth
Solar Radiation
Solar energy affects various biomes and climates, determined by seasonal changes, daily light variation, and solar angles.
Equatorial Regions: Experience more consistent solar radiation; angles are more direct.
Higher Latitudes: Radiation is spread over larger areas due to Earth's curvature.
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Seasonal Changes
Tilt and Orbit: Earth's tilt influences sunlight exposure, leading to distinct seasons.
Equinoxes: Occur in spring and fall, marking equal day and night lengths.
Solstices: Mark extremes of sunlight and darkness.
Earth's Geography and Climate
Influencing Factors
Intensity of solar radiation varies with season and geographical factors.
Earth's elliptical orbit influences climatic variations.
Greenhouse Gases: Human activities contribute to climate change by increasing atmospheric warming.
Volcanic Eruptions: Release ash and gases, temporarily cooling the Earth.
Ocean Currents: Store and redistribute Earth's heat, significantly impacting climate.
Land Masses: Affect air mass movement, precipitation patterns, and temperature variations through phenomena like the rain shadow effect.
El Niño and La Niña Effects
El Niño Characteristics
Definition: Warming of Pacific Ocean waters due to weakened trade winds.
Result: Increased precipitation in typically dry coastal areas but colder, harsher winters in other regions.
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La Niña Characteristics
Definition: Cooling of Pacific Ocean waters due to strengthened trade winds.
Effect: Cooler, wetter conditions in certain areas, drier in others.
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Global Impact
Both phenomena can lead to drastic shifts in ecosystems, species migration, and significant weather events such as flooding or droughts.
Watershed Characteristics
Definition
A watershed collects runoff directing it towards a main discharge point (usually the lowest elevation point).
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Structure
Headwaters: Begin the watershed, often separated by high elevations like mountains.
Runoff flows through streams and rivers, discharging into larger bodies of water.
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Factors Influencing Watershed Efficiency
Size, length, slope, soil type, and vegetation all impact watershed productivity and runoff management.
Steeper slopes enhance runoff due to gravity assistance.
Soil composition and vegetation play roles in filtration and erosion protection.