Water and Carbon Cycle Flashcards
What is an ecosystem?
The interrelationships between living and non-living components within a particular environment
What type of system is the ‘water cycle’?
Closed system in its entirety
Open system at a local level because there are inputs, outputs and flows
What type of system is the ‘carbon cycle’?
Global scale- closed system
Local scale-open system due to inputs and outputs
What are the 6 main spheres?
Biosphere Lithosphere Cryosphere Atmosphere Pedosphere
Where is the majority of the total water supply stored?
96.6% saline water
How much of the world’s water is saline?
97.4%
How much of the Earth’s water is freshwater?
2.5%
What are the major stores of freshwater?
Snow and ice
Groundwater
What is an aquifer and how much water is stored globally by them?
30% of all freshwater
Water stored in rocks deep below the ground surface in underground reservoirs
Where do aquifers form? Why?
Areas made up of rocks such as chalk and sandstone, which are porous and permeable
What is the soil water budget?
A soils capacity to store and transfer water
What is the ‘water table’?
The upper layer of saturated rock which rises and falls in response to groundwater flow, water abstraction or recharge.
Define ‘precipitation’
Transfer of water from the atmosphere to the ground
Takes the form of snow, rain, hail or dew
Define evaporation
Transfer of water from liquid state to gaseous state.
Define condensation
Transfer of water from a gaseous state to a liquid state
Define sublimation
Transfer from a solid state to gaseous state
Define interception
Water intercepted and stored on leaves of plants
Define overland flow
The transfer of water over the land surface
Define infiltration
Transfer of water from ground surface into soil where it may then percolate into underlying rocks
Define throughflow
Water flowing through the soil towards a river channel
Define percolation
Water soaking into the rocks
Define groundwater flow
Transfer of water very slowly through the rock
How much of the land was covered by glaciers during end of last ice age?
1/3 of Earth’s land area
What model can be used to illustrate cloud formation?
The Global Atmospheric Circulation Model
How do clouds form at the equator?
High temperatures= high rates of evaporation
Warm air rises, cools and condenses to form towering banks of cloud
Heavy rainfall occurs in the ITCZ ( intertropical convergence zone)
What happens to the ITCZ seasonally? Why?
Moves North and South due to changes in the intensity/ direction of the sun
How do clouds form at mid latitudes?
Convergence of warm air from tropics and cool air from the Arctic
The polar front (boundary of the two) causes rising air and cloud formation
Strong upper level winds drive these towards UK
What is the largest store of water after oceanic water?Where is it stored?
Ice
95% locked up in two ice sheets Antarctica and Greenland
Explain the feedback loop seen on glaciers
Positive feedback loop
Sea levels destabilise ice shelves
Triggers calving
Further melting occurs
Explain the effects of farming on the hillslope water cycle
Ditches drain the land
Irrigation increases the amount of water on the ground
Explain the effects of urbanisation on the hillslope water cycle
Infrastructure provides an impermeable surface so there is reduced infiltration
Deforestation occurs too which further reduces interception and infiltration
Water runs through pipes to the nearby river channels
Explain the effects of deforestation on the hillslope water cycle
The removal of trees reduces interception and infiltration
Overland flow increases
Explain what the soil water budget looks like during the wet season
Precipitation exceeds evapotranspiration Water surplus Ground water stores fill with water Increased surface run off Higher discharge River levels rise
Explain what the soil water budget looks like during the dry season
Evapotranspiration exceed precipitation
Ground water store depletion
Water (some) flows into river channel and not replaced by precipitation
What is field capacity?
How much water soil can hold without any outputs occuring
What is a drainage basin?
An area of land that is drained by a river and its tributaries
What is the watershed?
The boundary of a river basin
Define stem flow
The process of waster dripping through the leaves down the stems
What is a rill?
A concentrated small channel where water unable to infiltrate flows
Give the equation for water balance
P =O + E +/- S
P= precipitation O= total runoff E= evapotranspiration S= storage
Define river discharge
The volume of water that flows through a given area in a given time
Give the equation for river discharge
Discharge= cross sectional area x velocity
What does a flood hydrograph show?
The discharge of a river following a particular storm event
What is a flashy hydrograph?
A hydrograph with a short lag time and a high peak
What is the lag time?
The time between peak rainfall and peak discharge
What characteristics create a flashy hydrograph?
Small basins High drainage density Impermeable rocks Urbanisation Steep slopes Saturated soil Heavy rain exceeding infiltration capacity
What characteristics create low, flat hydrographs?
Large basins Slow water transfer Permeable rocks Forests Gentle slope Dry soil Light rain
What are the natural variations that can cause change in the water cycle?
Extreme weather events such as storms and droughts
Explain the effects on the water cycle during the Californian drought
Drought caused reduction in water stores
Vegetation dies back so limited transpiration, interception and infiltration
Ground water flow
High initial rates of evapotranspiration due to heat
Soil dries out so less through flow
How can land use impact the water cycle?
Urbanisation, impermeable surfaces reduce infiltration
Deforestation, removal of trees= surface run off and soil erosion
How is irrigation in the Middle East impacting water stores?
Water being abstracted from thousand year old aquifers
Risk of depletion
Rate of recharge slower than formation
What are the main stores of carbon?
Lithosphere Hydrosphere Cryosphere Atmosphere Biosphere
Define ‘carbon sink’
A store that absorbs more carbon than it releases
What is the largest store of carbon? How much does it contain?
Marine sediments and sedimentary rocks.
100,000 billion metric tonnes
What is photosynthesis?
The process whereby plants use the light energy from the sun to produce carbohydrates in the form of glucose
How does decomposition link to the carbon cycle?
Organisms die
Decomposers consume them
Carbon from the bodies of the organisms is returned to the soil as CO2
How does combustion link to the carbon cycle?
Organic material contains carbon and is burnt which releases carbon dioxide into the atmospere
Define carbon sequestration
Transfer of carbon from atmosphere to plants, soils, rock formations and oceans
How does weathering link to the carbon cycle?
Weathering breaks down the rocks CO2 is absorbed by rainwater and forms carbon acid Rocks dissolve Carbon held in solution Transported and used in shell formation
