Earth’s Life Support System Part 1 Flashcards
On a global scale, is the water cycle a closed or open system?
Closed system
On a global scale, is the carbon cycle a closed or open system?
Closed system
On a smaller scale, is the water cycle a closed or open system?
Open system
On a smaller scale, is the carbon cycle an open or closed system?
Open system
What are the stores in the water cycle, from smallest or largest?
Atmosphere
Land
Ocean
What are the flows in the water cycle?
Precipitation
Runoff/groundwater flow
Evapotranspiration
What are the stores in the global carbon cycle, from smallest to largest?
Atmosphere
Fossil fuels
Sea floor sediments
Oceans
Sedimentary rocks
How much carbon does sedimentary rocks hold?
99% of the carbon is stored in sedimentary rocks
How are sedimentary rocks formed?
Formed by shells and mud at the bottom of the ocean floor and become compressed over millions of years.
What are the flows in the global carbon cycle?
Photosynthesis
Respiration
Oxidation
Weathering
What percentage of water is stored in the Earth’s oceans?
97%
What is the percentage of water stored in polar ice and glaciers?
2%
How is water stored in the atmosphere?
Water vapour
Why is there a very small amount of water found in the atmosphere?
The rapid flux of water in and out of the atmosphere.
What’s evapotranspiration?
Water can be evaporated from oceans and soils and vapour can be transpired from plant leaves.
How does moisture leave the atmosphere?
As precipitation and condensation.
What’s percolation?
When water flows down through soil layers and underlying rock is pulled down by gravity.
What’s through flow?
Water that’s transferred through the soil.
What’s groundwater flow?
Where water reaches impermeable bedrock below ground and it flows over the surface of rock.
What are the two types of carbon cycles?
Fast
Slow
What’s the slow carbon cycle?
Carbon is stored in rocks, sea floor sediments and fossil fuels and is held in rocks for around 150 million years.
How is carbon stored in the slow carbon cycle?
CO2 is dissolved in oceans and is used by coral to make shells by fixing the dissolved carbon with calcium to form calcium carbonate.
Then converted into sedimentary rocks as become compressed at bottom of the ocean.
What are the two ways carbon is returned to the atmosphere from sedimentary rocks?
Tectonic activity
Chemical weathering
How does tectonic activity return carbon into the atmosphere from sedimentary rocks?
Subduction of carbon rich rock at ocean trenches can result in the venting of carbon to atmosphere during volcanic eruption.
How is carbon returned to the atmosphere from sedimentary rocks by chemical weathering?
Erosion/tectonic movement can expose rocks and weathering processes such as carbonation which releases CO2 to the atmosphere.
How does Phytoplankton absorb CO2?
Phytoplancton in oceans absorb CO2 for photosynthesis. Part of the fast carbon cycle
What is the fast carbon cycle?
The most rapid circulation of carbon between the atmosphere, oceans, living organisms and soils.
What is the water balance?
The balance between the inputs and outputs of a drainage basin system.
What is the water budget equation?
P=Q+E+R-change in storage
P=precipitation
Q=runoff
Why will the water balance vary?
depends on the location and climate
What is the drainage basin system?
The drainage of water back into rivers, lakes, or oceans to be used again.
Is the drainage basin system open or closed?
open
What is stem flow?
Water falling down a tree trunk
What is throughfall?
Water falling from tree to the floor.
What is precipitation?
Any form of atmospheric moisture falling from clouds.
What are example of precipitation?
snow, rain, sleet, hail
How do clouds form?
When water vapour cools to its dew point.
What is the dew point?
The critical temperature when the air becomes saturated and cannot hold anymore vapour, creates a change in state to water droplets.
What are the 2 theories for how rain develops?
Collision theory
Bergeron-Findeisen theory
What is the collision theory for the formation of rain?
In places where air is too warm for ice crystals precipitation occurs as tiny droplets collide into one another and stick together.
What’s Bergeron-Findeinsen’s Theory for the development of rain?
It takes place when ice crystals form in high altitudes, growing gradually bigger.
The vapour pressure drops which allows the droplets to evaporate and become smaller ice crystals.
As become bigger and heavier they fall through warmer parts and rain occurs.
What are the three types of rainfall?
Convectional
Relief
Frontal
How does convectional rainfall occur?
The ground is heated to an extent where the air above it becomes warmer than the surroundings so expands and rises. It cools further as it rises and more clouds develop.
What area is most commonly associated with convectional rainfall?
equatorial areas, where more intense insulation occurs.
What type of clouds would we typically find with convectional rainfall?
cumulonimbus and often have thunderstorms
How does relief rainfall occur?
Moist air if forces over a mountain and its ability to hold water vapour decreases, so rainfall occurs.
What’s the rain shadow effect?
When the water vapour increases on the leeward side of the mountain so lower relief rainfall.
How does frontal rainfall occur?
Occurs as a result of the meeting of two different air masses with different characteristics.
Less dense, warmer air if forced up above the cooler and steady rainfall occurs.
What are the factors that are dependent as to whether rainfall occurs?
air rising and cooling
condensation- development of clouds
presence of moisture
What are the factors of variation of rainfall?
Intensity
Duration
Seasonal variability
What’s intensity of rainfall?
The amount of precipitation falling in a given time.
What would be classed as high intensity precipitation?
10-15mm/hr
What happens to rain when it reaches the ground?
Will flow into streams or rivers, where dome will be direct channel catch whilst others will infiltrate and travel by either throughflow or groundwater flow.
What is transpiration?
The process by which moisture is lost in the form of water vapour to the atmosphere through the stomata of leaves.
Where does water leave in a leaf?
stomata
How much moisture in the atmosphere is from transpiration?
10%
What factors affect transpiration?
Temperature
Wind speed
Relative humidity
Soil moisture levels
How does temperature affect transpiration?
Temp increases so does transpiration
How does wind speed affect transpiration?
increased wind around the plant increases transpiration
How does the relative humidity affect transpiration?
More humid air means lower transpiration
How does soil moisture levels affect transpiration?
Lack of moisture then less transpiration as leaf loss occurs
What’s condensation?
The change from water vapour to liquid.
Occurs when air is cooled to dew point and air is saturated so condenses.
What are 4 different types of clouds?
Cirrusform
cumuloform
stratiform
nimboform
What are cirrusform clouds?
High level clouds that can look like curls of hair.
What are cumuloform clouds?
They can look detatched, low level clouds.
Look like cotton balls.
What are stratiform clouds?
Layer of cloud, low/middle of the atmosphere.
What are nimboform clouds?
rain clouds
What does it mean by stable air?
The clouds aren’t moving
What does it mean by unstable air?
The clouds are moving
What is dew?
condensed moisture forming as small drop on relatively cold surfaces
When does dew occur?
occurs when the ground objects become cooler in comparison to the surrounding area and usually appears in the early morning or evening.
What’s fog?
It’s a thick cloud close to the surface that reduces visibility.
When does fog occur?
occurs when the air becomes too cold to hold its moisture
What are the two processes for fog to occur?
cooling
evaporation
What are the 6 carbon exchange processes?
Precipitation
Weathering
Photosynthesis
Decomposition
Respiration
Combustion
How is carbon exchanged by precipitation?
Weak carbonic acid is formed as atmospheric CO2 is dissolved in rainwater.
How does chemical weathering exchange carbon?
Releases carbon from limestone to streams, rivers, atmosphere.
How much carbon is believed to be transferred to the atmosphere/oceans per year by chemical weathering?
0.3 billion tonnes of
How does photosynthesis exchange carbon?
Uses carbon dioxide with water to form glucose and oxygen in plants.
How does decomposition exchange carbon?
Dead organic matter, for example bacteria and fungi, releases CO2 to the atmosphere.
What areas have high levels of carbon exchange by decomposition?
Warm, humid areas such as a rainforest.
How does respiration exchange carbon?
Releases carbon dioxide.
It is the reverse of photosynthesis.
What are the two most important processes in the fast carbon cycle?
Photosynthesis and respiration
How does combustion exchange carbon?
When organic matter burns in the presence of oxygen it releases CO2 and other gases.
How does fog occur by cooling?
Air is cooled to its dew point
How does fog occur by evaporation?
Water vapour is mixed white air by evaporation until the air is saturated.
What are the three types of lapse rates?
Environmental
Dry adiabatic
Saturated adiabatic
What is a lapse rate?
The temperature change with the increase in height.
What is an environmental lapse rate?
On average temp falls by 6.5 degrees for every km increased in height.
What is a dry adiabatic lapse rate?
The rate at which a parcel of dry air (less than 100% humidity) cools, due to adiabatic expansion.
Every km increased the temp falls by 10 degrees.
What is a saturated adiabatic lapse rate?
The rate at which a saturated parcel of air will cool as it rises through the atmosphere.
Every km the temp falls by 7 degrees.
When does absolute instability occur?
When the dew point is met so condensation occurs.
What is evaporation?
The process by which liquid from water surfaces is transformed into water vapour.
What is evaporation driven by?
Energy from air movement (wind) and the sun.
What does the evaporation rates depend on?
Temperature
Windspeed
Hours of sunshine
Humidity
Vegetation cover
Albedo
How does humidity affect humidity?
A high humidity mean less evaporation
How does albedo affect evaporation?
High albedo means slower evaporation.
What is interception?
Water retained by surfaces which may be lost by evaporation back to the atmosphere.
How may water be lost from a tree when intercepted?
Through fall
Stem flow
Interception loss
How does deforestation affect flood risk?
Increases flood risk
What does interception depend on?
The nature of rainfall
Duration of rainfall
Season
How does the nature of rainfall affect interception rates?
Greater intensity rainfall means less interception.
How does the season affect interception rates?
Deters amount of rainfall and potential evapotranspiration.
What is interception loss?
The moisture that evaporates from the surface of branches, leaves and stem.
What factors affect interception loss?
Interception storage capacity
Wind speed
Vegetation type
Tree species
What is infiltration?
The movement of water from the ground surface downwards into the soil.
What is infiltration capacity?
The maximum rate at which soil in a given condition can absorb water.
What are the factors that affect infiltration rates?
Type of rainfall
Type of soil
Vegetation
Deforestation
Relief
What is throughflow?
The lateral movement of water to reach the river channel after infiltration
What is overland flow?
The movement of water over the surface of the ground to streams and river channels
What are the two reasons for overland flow?
infiltration capacity has been exceeded.
the soil becomes saturated and so the water table rises to the surface.
Where does surface runoff tend to occur?
Thin soil
Clay soil
Thin vegetation
Long gentle slopes
Urban areas
What percentage of freshwater comes from groundwater?
96.5%
Where can groundwater flow be found?
the zone of saturation
What is the upper layer of the saturated zone called?
water table
What is ablation?
the loss of ice from snow, ice sheets and glaciers.
What is sequestration?
The take up and long term storage of carbon dioxide.
Where does sequestration occur?
Naturally in oceans and some land based vegetation.
What is the physical pump of sequestration in oceans?
These move carbon compounds to different parts of the ocean in downwelling and upwelling currents
Downwelling occurs in parts of the ocean where cold, denser water sinks.
These currents bring dissolved bring dissolved carbon dioxide down to the deep ocean.
Once there, it moves in slow-moving deep ocean currents, staying there for hundreds of years.
Eventually, these deep ocean currents, part of the thermohaline. circulation, return to the surface by upwelling.
The cold deep ocean water warms as it rises towards the ocean surface and some of the dissolved carbon dioxide is released back into the atmosphere.
What is the biological pump of sequestration in oceans?
Driven by marine organisms such as phytoplankton.
Where does carbon in phytoplankton end up?
Decomposing and releasing CO2 into oceans.
Accumulating on ocean floor in sediments.
How does sequestration in plants occur?
photosynthesis.
