earth systems and resources

Geological time scale

A system of chronological dating that relates geological strata (rock layers) to time. It divides Earth's history into eons, eras, periods, epochs, and ages, based on significant geological or paleontological events.

Plate tectonics

A scientific theory explaining the large-scale motion of Earth's lithosphere (the rigid outer shell). The lithosphere is divided into tectonic plates that move, interact (collide, separate, or slide past each other), and cause earthquakes, volcanic activity, and mountain building.

Earthquakes

Sudden, violent shaking of the ground caused by the movement or rupture of Earth's tectonic plates. The energy released from these ruptures travels as seismic waves.

Volcanism

Geological processes involving the movement of magma (molten rock) to or near the Earth's surface. This includes volcanic eruptions, the formation of volcanic landforms, and the release of gases.

Seasons

The four periods of the year (spring, summer, autumn/fall, winter) characterized by changes in weather patterns, temperature, and daylight hours. These are caused by the Earth's tilted axis and its revolution around the Sun.

Solar intensity

The amount of solar radiation (sunlight) received at a particular location on Earth's surface. It varies depending on factors such as latitude, time of year, and atmospheric conditions.

Latitude

The angular distance of a location north or south of the Earth's equator, measured in degrees. Latitude significantly affects climate and solar intensity.

Composition

This refers to the mixture of gases that make up the atmosphere. Primarily, this is nitrogen (N₂) and oxygen (O₂), but also includes trace gases like argon (Ar), carbon dioxide (CO₂), water vapor (H₂O), and others which play crucial roles in climate and weather.

Structure

This describes the vertical layering of the atmosphere based on temperature gradients. Key layers include the troposphere (where weather occurs), stratosphere (containing the ozone layer), mesosphere, thermosphere, and exosphere. Each layer has unique characteristics regarding temperature, pressure, and composition.

Weather and climate

Weather refers to the short-term state of the atmosphere at a particular time and place, encompassing elements like temperature, humidity, precipitation, wind, and cloud cover. Climate, on the other hand, represents the long-term average weather patterns over a region, typically spanning decades or longer.

Atmospheric circulation and the coriolis effect

Atmospheric circulation describes the large-scale movement of air masses driven by differences in temperature and pressure. The Coriolis effect is an inertial force caused by Earth's rotation that deflects moving air (and water) to the right in the Northern Hemisphere and to the left in the Southern Hemisphere, influencing wind patterns and the formation of weather systems.

Atmosphere-ocean interactions

This encompasses the complex exchanges of energy, momentum, and water between the atmosphere and the ocean. Ocean currents significantly influence atmospheric temperature and humidity, while atmospheric winds drive ocean currents. This two-way interaction is crucial for shaping global climate patterns.

ENSO( El Niño southern oscillation)

ENSO is a naturally occurring climate pattern characterized by fluctuations in sea surface temperatures in the central and eastern tropical Pacific Ocean. These temperature variations influence atmospheric pressure patterns and have far-reaching impacts on global weather, causing droughts in some regions and floods in others.

Fresh water/ saltwater

This refers to the fundamental distinction between water bodies based on their salinity. Freshwater has low salt concentration (<0.5 ppt), typically found in rivers, lakes, and groundwater. Saltwater, conversely, has a high salt concentration (>30 ppt), primarily found in oceans and seas. The interaction and balance between these two types of water are crucial for many ecosystems.

Ocean circulation

This describes the large-scale movement of ocean water, driven by factors like wind, temperature differences (thermohaline circulation), and the Earth's rotation (Coriolis effect). Ocean currents transport heat, nutrients, and organisms globally, influencing weather patterns and marine ecosystems.

Agricultural, industrial and domestic use

This encompasses the various ways humans utilize water. Agriculture relies heavily on irrigation; industries use water in manufacturing processes; and domestic use includes drinking, sanitation, and other household needs. Sustainable water management necessitates balancing these demands

Surface and ground water issues

This category covers problems related to both surface water (rivers, lakes, etc.) and groundwater (water beneath the Earth's surface). Issues include pollution (from agriculture, industry, or sewage), depletion (over-extraction), and changes in water quality or availability due to climate change or land use.

Global problems

This refers to the worldwide challenges associated with water scarcity, pollution, and mismanagement. These problems impact food security, human health, economic development, and international relations. Climate change exacerbates these issues.

Conservation

This involves the sustainable use and protection of water resources. Strategies include reducing water consumption, improving irrigation efficiency, preventing pollution, and protecting watersheds to ensure future water availability.

Rock cycle

The rock cycle is a continuous process describing the transformation of rocks from one type to another. It involves three main rock types (igneous, sedimentary, and metamorphic) and the processes that change them (weathering, erosion, deposition, melting, metamorphism). Think of it as a continuous loop where rocks are constantly being created, destroyed, and reformed.

Soil formation

a complex process involving the weathering of rocks and minerals, the decomposition of organic matter, and the interaction of these materials with water, air, and living organisms. It's a slow, gradual process that occurs over long periods, creating distinct layers or horizons within the soil profile. The factors influencing soil formation (often remembered by the acronym CLORPT) are: Climate, organisms, topography, parent material, and time.

Soil composition

Soils physical and chemical properties

Main soil types

Soils are classified based on their texture (proportions of sand, silt, and clay) and organic matter content. The main types include sandy soils (well-drained but poor water retention), silty soils (moderate drainage and fertility), clay soils (poor drainage but good water retention), peaty soils (high organic matter), and loam soils (a balanced mix of sand, silt, and clay, considered ideal for agriculture)

Erosion and other soil problems

Erosion is the process of soil being transported by wind, water, or ice. Other problems include nutrient depletion (loss of essential plant nutrients), compaction (reduced pore space, hindering water infiltration and root growth), salinization (accumulation of salts, harming plant growth), and pollution (contamination by harmful substances)

Soil conservation

This involves practices to protect and improve soil quality. Techniques include terracing (creating level platforms on slopes to reduce erosion), contour plowing (plowing along the contours of slopes), crop rotation (alternating crops to maintain soil fertility), cover cropping (planting crops to protect the soil surface), and windbreaks (planting trees or shrubs to reduce wind erosion)