Water and carbon cycles
Systems in physical geography
Ecosystem: The interactions between biotic + abiotic components within a
particular environment.
Inputs
– Precipitation
– Less fall during the autumn
– Seeds carried by wind and birds
Outputs
– Water soaking through soil and roots
– Evaporation
– Seed dispersal
Stores/components
– Water
– Soil
– Plants
Flows/transfers
– Photosynthesis
– Infiltration
– Transpiration
A systems approach helps to understand the physical + human world.
It shows how energy is transferred between components + how they
change - natural + human.
Systems term Definition Drainage basin Woodland carbon
cycle
Input Material or Precipitation Precipitation with
energy moving dissolved carbon
into the system dioxide (CO2)
from outside
Output Material or Runoff Dissolved carbon
energy moving within runoff
from the system
to the outside
Energy Power or driving Latent heat Production of
force associated with glucose through
changes in the the process of
state of water photosynthesis
Stores/ The individual Trees, puddles, Trees, soil, rocks
components elements of parts soil
of a system
Flows/transfers The links or Infiltration, Burning,
relationships groundwater absorption
between the flow, evaporation
,Energy Power or driving Latent heat Production of
force associated with glucose through
changes in the the process of
state of water photosynthesis
Stores/ The individual Trees, puddles, Trees, soil, rocks
components elements of parts soil
of a system
Flows/transfers The links or Infiltration, Burning,
relationships groundwater absorption
between the flow, evaporation
components
Positive feedback A cyclical Rising sea levels Increased temps
sequence of (due to thermal due to climate
events that expansion and change cause
amplifies or melting melting of
increases freshwater ice) permafrost.
change. Positive can destabilise Trapped
feedback loops ice shelves, greenhouse
exacerbate the increasing the gases are
outputs of a rate of calving. released,
system, driving it This leads to an enhancing the
in one direction increase in greenhouse
and promoting melting, causing effect, raising
environmental sea levels to rise temps further
instability further
Negative A cyclical Increased Increased
feedback sequence of surface temps atmospheric CO2
events that lead to an leads to
damps down or increase in increased temps,
neutralises the evaporation from promoting plant
effects of a the oceans. This growth and rates
system, leads to more of
promoting cloud cover. photosynthesis.
stability and a Clouds reflect This in turn,
state of dynamic radiation from the removes more
equilibrium sun, resulting in a CO2 from the air,
slight cooling of counteracting the
surface temps rise in temp
Dynamic This represents a Remote and Same as left
equilibrium state of balance unaffected
within a drainage basin/
constantly woodland where
changing system there has been
no significant
natural or human
impacts, or one
that has had time
to adjust to
change
,Isolated, closed or open systems
Earth’s 4 major subsystems: atmosphere, lithosphere, hydrosphere +
biosphere - overall cascading system
The water cycle system
In its entirety, it is a closed system - water is not lost to or gained.
At a local scale e.g. a drainage basin is an open system.
The carbon cycle system
Global - closed system
At a local scale e.g. a forest is an open system.
The global water cycle
Water is our most precious resource and essential for life on Earth. It is
constantly recycled, stored + transferred between land, oceans +
atmosphere. It is not evenly distributed. Some enjoy plentiful supplies,
others suffer severe shortages causing migration + famines.
Ownership of water is a controversial political issues. Future wars may be
about securing water supplies.
Stores
Most water is stored as saline (salt) water in oceans. The main stores of
freshwater - ice sheets + groundwater. Rivers, lakes + atmosphere contain
small amounts of water.
Transfers
Processes of transferring water between stores e.g. precipitation -
atmosphere to earths surface - evaporation - back to the atmosphere.
, The main stores in the water cycle
Lithosphere (land)
Hydrosphere (liquid water) - water on or close to the Earth’s surface
Cryosphere (frozen water)
Atmosphere (air)
Total global water
Oceans - 96.6%
Other Saline Water - 0.9%
Freshwater - 2.5%
Freshwater
Glaciers, ice caps and sheets - 68.7%
Groundwater - 30.1%
Surface/other freshwater - 1.2%
Surface/other freshwater
Ground ice and permafrost - 69.0%
Lakes - 20.9%
