U2 The Physical Environment EVS

Ablation

The loss of ice and snow, especially from a glacier, through melting, evaporation, and sublimation.

Abstraction

The extraction of water from rivers and boreholes for public water supply, agriculture, etc.

Acidification

A process in which the pH drops as the conditions become more acidic.

Activated carbon filters

Particles of activated carbon are used to remove organic chemicals such as pesticides which absorb onto the carbon particles.

Active layer

The near surface layer in a periglacial environment which seasonally freezes and thaws.

Aeration

Bubbles of air or water sprays are used to aerate the water and ensure a high dissolved oxygen content.

Aerobic process

A process that takes place in the presence of oxygen.

Afforestation

Planting trees to increase the area of forest.

Albedo

A measure of the reflectivity of a surface; surfaces that reflect all light have an albedo of 100%, while those that absorb all light have an albedo of 0%.

Albedo effect

Global temperature rise leads to land-based & sea ice melt, exposing darker surfaces that absorb more radiation.

Alluvial deposits

Deposits formed by the flow of water; materials carried by rivers that are deposited, such as gold, diamonds, gravel, sand, and clay.

Ammonification

The release of ammonium ions by bacteria, fungi, and detritivores as they decompose dead organic matter.

Anaerobic process

A process that takes place in the absence of oxygen.

Anthropogenic

Adjective describing outcomes caused by human activities.

Aphotic zone

Deeper layers of water that receive no sunlight because they are absorbed by shallower layers.

Aquifer

An underground permeable and porous rock which contains water that is abstracted by humans.

Artificial recharge

Water is pumped underground during times of surplus to replenish groundwater supplies.

Atmosphere

The gases surrounding the Earth, characterized by temperature, density, turbulence, and composition.

Basalt

Lava that has cooled and solidified.

Batholith

A very large body of igneous rock in the Earth's crust.

Biogeochemical cycle

A series of linked processes which use and reuse elements such as carbon, nitrogen, phosphorus, iron, and sulfur.

Bioleaching

A method of using bacteria to dissolve metals from low grade ores.

Biological sediments

Mineral deposits formed by living organisms, such as shells crushed together under pressure.

Biological weathering

The breakdown of rocks through the chemical and physical action of living organisms.

Biomass

The total mass of living or recently living material in an area.

Biosphere

The space at the Earth’s surface and within the atmosphere occupied by living organisms.

Canopy

The uppermost layer of treetops and branches in a forest or woodland ecosystem.

Capillary action

The ability of water to rise toward the ground surface through tiny pore spaces in clay soils.

Carbon capture & storage (CCS)

A method to reduce carbon dioxide emissions by capturing and storing the gases in underground geological structures.

Carbon credits

Allowances that permit given levels of CO2 emissions by businesses, which can be traded.

Carbon fertilisation

Increased temperatures increasing rates of photosynthesis and carbon absorption by trees.

Carbon footprint

An estimate of the total releases of greenhouse gases caused by an individual, group, or activity.

Carbon offsets

A market-based approach to limiting carbon emissions through trading carbon quotas.

Carbon sequestration

Any process which removes carbon dioxide from the atmosphere.

Carbon sink

A long-term store of carbon in ocean sediments, carbonate rocks, and forests.

Catchment area

The area drained by a river and its tributaries.

CFCs

Chlorofluorocarbons; ozone-depleting gases emitted from aerosols and refrigerators.

Chemical analysis

Laboratory tests confirming the chemical composition and purity of minerals.

Circular economy

A model involving sharing, leasing, reusing, repairing, refurbishing, and recycling to reduce waste.

Cirrus clouds

Thin, wispy clouds usually found above 6000m altitude.

Combustion

The process of burning.

Condensation

The phase change of water vapor to water.

Continental drift

The movement of tectonic plates that forms new mountain ranges.

Contour cropping

A soil erosion control measure where land is cultivated by ploughing horizontal furrows.

Convection

The motion of a gas or liquid where warmed material rises and cool material sinks.

Cryosphere

All the frozen water on Earth.

Cradle to cradle (C2C)

Designing items so that all materials can be reused or disposed of without causing harm.

Dead organic matter

Fresh residues consisting of dead microorganisms, insects, and old plant roots.

Decomposers

Organisms that break down dead organic matter, releasing nutrients.

Dendrochronology

The method of determining the age of wood using growth rings.

Denitrification

The chemical reduction of nitrates to nitrogen gases by bacteria, reducing soil fertility.

Desalination

The process of converting saltwater into freshwater.

Detritivores

Animals that ingest and digest dead organic matter.

Distillation

The process of boiling water and collecting the steam as purified liquid.

Dobson units

Units used to measure ozone in the atmosphere.

Downwelling

The sinking of dense, salty (or cold) water in oceans.

Dynamic equilibrium

A balance created by active processes that cancel each other out.

El Niño

Events when wind and ocean currents in the equatorial Pacific Ocean slow significantly or reverse.

Enhanced greenhouse effect

The acceleration of the natural greenhouse effect due to human emissions.

ENSO

El Niño Southern Oscillation; variations in sea surface temperatures and weather patterns in the Pacific.

Estuary

Where a river meets the sea.

Estuary barrage

A freshwater reservoir created by building a dam where a river enters the sea.

Eutrophication

Accelerated algal growth caused by excess nutrients in water.

Evaporation

The process by which liquid water is converted into gas.

Evaporites

Deposits formed when a sea evaporates, leaving behind salt crystals.

Evapotranspiration

Combined loss of water at the surface through evaporation and transpiration by plants.

Feedback mechanisms

Processes where an action affects the original process, either increasing or reducing it.

Filtration

The use of filters to remove solids and bacteria from water.

Finite

A resource that cannot replenish once depleted.

Fixation

The process where microorganisms reduce nitrogen to ammonia.

Flocculation

Particles clustering together, facilitated by adding flocculants.

Fluoridation

The addition of fluorides to water for dental health.

Forest & peat fires

A positive feedback mechanism where increased temperatures lead to droughts and fires.

Fossilisation

The incomplete decomposition of organic matter under anaerobic conditions.

Fractional crystallisation

The process where less soluble minerals crystallise first.

Glacier

A large body of dense ice moving over land under its own weight.

Gravimetry

A geological exploration technique detecting changes in gravity force.

Greenhouse effect

The natural process by which Earth maintains habitable temperatures.

Greenhouse gas

A gas that absorbs infrared radiation emitted by Earth's surface, causing heating.

Grey water

Domestic wastewater from homes that can be re-used for other purposes.

Groundwater

Water stored underground in permeable and porous rocks known as aquifers.

Groundwater flow

The horizontal movement of water within aquifers.

Guano

Phosphorous-rich bird feces.

Haber process

The industrial process that combines nitrogen and hydrogen to produce ammonia.

Homeostasis

The maintenance of a state of equilibrium.

Hydrology

The study of the movement, distribution, and properties of water in the environment.

Hydrosphere

All the water on Earth in solid, liquid, or gaseous form.

Hydrothermal deposition

Deposition of minerals from hot mineral-rich solutions.

Iceberg

A large piece of ice floating in the sea that broke off a glacier.

Ice cap

Ice covering an area less than 50,000 km² that is thick enough to have its own topography.

Ice field

Ice covering an area less than 50,000 km² with topography following the underlying land.

Ice sheet

Ice covering an area over 50,000 km².

Ice shelf

A floating mass of ice attached to land ice that flows into the sea.

Igneous rock

Rocks created by the cooling and hardening of magma or molten lava.

Incineration

The breakdown of waste by burning.

Inferred reserves

Predictions of mineral presence based on geological structures without economic estimations.

Infiltration

The vertical movement of rainwater through the soil.

Infiltration capacity

The maximum rate at which gravity pulls water into the soil.

Insolation

Sunlight that reaches a particular location.

Inter-basin transfers

Moving water from areas with a surplus to those with a shortage through canals and pipes.