Geography - Earths Life Support Systems - Key terms

Carbon Sink

a forest, ocean, or other natural environment viewed in terms of its ability to absorb carbon dioxide from the atmosphere.

Greenhouse gas

a gas that contributes to the greenhouse effect by absorbing infrared radiation

Open system (water cycle)

System which has inputs, throughputs and outputs

Closed system (water cycle)

Continuously cycles around, nothing is lost or gained

Evaporation

Process by which liquid water is converted into a gaseous state

Transpiration

Evaporated moisture from pores on a leaf surface or plant stomata

Evapotranspiration

Loss of water through evaporation and transpiration

Condensation

State change of water vapour to liquid water

Precipitation

Moisture falling from clouds towards the ground (snow, rain, hail...)

Ablation

Loss of ice and snow through melting + submilation

Submilation

State change of water from ice to vapour

Groundwater flow

Horizontal movement of water within aquifers

Interception

Rainwater stored in leaves and stems which is then evaporated

Infiltration

Vertical movement of rainwater through soil

Throughflow

water flowing horizontally through soil into rivers

cryospheric processes

Processes which occur in areas of dominant ice

Phytoplankton

plankton consisting of microscopic plants which photosynthesises using light

Respiration

a process in living organisms involving the production of energy, typically with the intake of oxygen and the release of carbon dioxide from the oxidation of complex organic substances

Photosynthesis

the process by which plants use sunlight to synthesize nutrients from carbon dioxide and water

Dew point

the atmospheric temperature below which water droplets begin to condense and dew can form.

Intensity (water cycle)

Amount of rain falling in a given time

Duration (water cycle)

Length of time that a precipitation event lasts for

Cumuliform clouds

flat based clouds with considerable vertical development when air is heated

Startiform clouds

Layer clouds which develop when air mass moves horizontally across a cooler surface

Cirrus clouds

Wispy clouds formed at high altitudes consisting of tiny ice crystals

Environment lapse rate (ELR)

Vertical temperature rise at any given time

Dry Adiabatic Lapse Rate (DALR)

Rate of which a parcel of dry air cools caused by adiabatic expansion

Saturated Adiabatic Lapse Rate (SALR)

Rate of which saturated air parcels cool as it rises through the atmosphere, condensation releases latent head

Latent heat

the heat required to convert a solid into a liquid or vapour, or a liquid into a vapour, without change of temperature

Through fall

the part of rainfall or other precipitation which falls to the forest floor from the canopy

Stemflow

Intercepted rain flowing down the trunk or stem of the plant

Meltwater

water formed by the melting of snow and ice, especially from a glacier.

Cyrosphere

The frozen water part of the Earths system

Overland flow

Water travelling across the grounds surface

Saturated overland flow

Movement of water across the ground (often as a film) when soil is saturated

Infiltration capactiy

Maximum rate the soil can store rainwater

Percolation

The movement of surface and soil water into underlying permeable rocks

Anthropogenic emissions

Emissions caused or influenced by humans

Weathering

The breakup of rocks in situ

Carbonation

mixing of water with carbon dioxide to make carbonic acid and when dissolved carbon dioxide in rainwater forms carbonic acid, and this acid reacts with minerals in rocks.

Freeze-thaw

Physical weathering breaking rocks down into smaller particles when water froze in between rocks expands

Chelation

Rainwater mixes with dead & decaying organic matter forming humic acids which attack rock minerals

Combustion

Organic material burns in the presence of oxygen, releasing Co2

Physical (inorganic) pump

Mixing of surface and deep ocean waters by vertical currents, creating an even distribution of carbon

Biological (organic) pump

the ocean's biologically driven sequestration of carbon from the atmosphere to deep sea water and sediment driven by marine organisms

Sequestration

The removal and storage of carbon from the atmosphere in carbon sinks through physical or biological processes

Climate

Long term weather patterns of an area

Weather

The state of the atmosphere at any given time

Icehouse earth

Interglacial periods are shorter when the earth is in this state, meaning more glacial periods.

Greenhouse earth

lack of ice and increase in global temperatures

Albedo

reflectivity of solar radiation by surfaces

Dynamic equilibrium

A state of balance between continuing processes

Negative feedback

Counters system change and restores equilibrium

Positive feedback

initial change causes further change

run-off

he draining away of water from the surface of an area of land

Lag-time

period of time from precipitation event to the peak flow

Borehole

a deep, narrow hole made in the ground, especially to locate water

Water table

the level below which the ground is saturated with water

Base flow

water input into streams and rivers from natural reservoirs

Aquifer

Water bearing rock (needs to be permeable and porous)

Permeable rock

Rock which is penetrated by water through pores, joints of faults

Porous rock

Rocks containing pores or airspaces between mineral particles

Groundwater

Water stores underground in permeable and porous rocks

artesian basin

An aquifer confined between impermeable rock

Artesian pressure

Hydrostatic pressure exerted on groundwater in a confined aquifer occupying a synclinal structure

Synclinal

downward folds