Water and Carbon Cycles: Systems Framework Flashcards
Define what a system is
A set of interrelated components working together towards some kind of process
What is an open system?
Matter and energy can enter and leave the system
What is a closed system?
Matter cannot leave the system, it can only cycle between stores, energy can enter and leave the system
What is dynamic equilibrium?
When there is disruption to one of the elements, so the other elements will change in order to return to a state of equilibrium, causing feedback loops
Disruptions:
Physical disruptions – storms or drought
Human disruptions – deforestation, urbanisation, water abstraction
Sudden disruptions may result in sudden change e.g. flooding
What is positive feedback?
The effects of an action are amplified or multiplied by subsequent secondary effects
What is negative feedback?
The effects of an action are nullified or reduced by subsequent secondary effects
What are elements?
A constituent part of the system
What is an attribute?
Characteristics of an element
What is a relationship?
the way in which the elements of a system interact
What are the inputs in the water cycle?
precipitation
matter and energy being added to the system
What are the outputs in the water cycle?
river discharge
matter or energy leaving the system
What are the stores in the water cycle?
ocean, groundwater, clouds
where matter or energy builds up
What are the flows in the water cycle?
channel flows
matter or energy moving from one store to another
What are the boundaries of the water cycle?
watershed
limits of the system
What is an example of a positive feedback loop?
Global temp rise -> warms oceans -> increased oceanic temperatures -> warm water is less able to dissolve gases -> dissolved CO2 is released by warmer oceans -> more CO2 back into atmosphere -> global temp rises
What is an example of a negative feedback loop?
burning fossil fuels increased atmospheric CO2 -> global temp increases -> more plant growth -> increased CO2 uptake by biosphere -> reduces atmospheric CO2 slowing rate of global temp increase
What is a threshold?
A point in a condition or process that, once passed, triggers some kind of change
Describe the varying sizes of global water stores
- oceanic stores is the largest, 1.4 sextillion litres of water which is 97% of all the water in the hydrosphere
- cryospheric store second largest (e.g. Ross Ice shelf or Greenland Ice sheets), 26 million km^3, contains 69% of freshwater (3% of all water is freshwater)
- terrestrial water next, rivers take up 1 million squared km, largest being the Amazon River
- biosphere second to last largest store, less than >1% of all freshwater, all living parts on the Earth
- atmosphere is the smallest store, clouds, rain, vapour, ice crystals, a store 10 million% smaller than ocean
Explain the sizes of the global water stores
- Large stores have the longest residency times as the scale of processes is small relative to their size and they return the same amount (e.g. hydrosphere and evaporation/precipitation)
- small stores have shorter residence times because the scale of the flows acting upon them are large relative to their size (e.g. atmosphere and evaporation/precipitation)
Describe the flows between water stores
- Evaporation, increases amount of water stored in the atmosphere, liquid water changes state into a gas
- Condensation, vapour changes to liquid water, decreases water stored in the atmosphere
- Cryospheric Processes, including accumulation and ablation, changes amount of water stored in cryosphere
What process are changing the size of the global water stores?
transpiration and respiration plant uptake percolation groundwater flow precipitation/condensation evaporation
What does the magnitude of each water store depend on?
The amount of water flowing between them
What factors control the size of flows between water stores?
- evaporation = solar energy, supply of water, humidity of the air and temperature of air
- condensation = amount of water in atmosphere, solar radiation and condensation nuclei
- cryospheric processes = global climate
What is the size of the largest water store?
Largest store is in the ocean with 1.3 million 1000km^3