Chapter 1
Water and carbon cycles
1.1 Systems frameworks and their application
System A system is an assemblage of interrelated parts that work together by way of some driving process.
They are a series of stores/components that have flows or connections between them.
Elements are the things that make up a system of interest, attributes are the perceived characteristics
of the elements and relationships are descriptions of how the various elements work together to carry
out some kind of process.
Common - They have a structure that lies within a boundary.
characteristics - They are generalisations of reality, removing incidental detail that obscures fundamental
of a system relationships.
- They function by having inputs and outputs of material that is processed within the components
causing it to change in some way.
- They involve flows of material between components.
Classification - Isolated systemsthey have no interactions with anything outside the system boundary. There is
of systems no input or output of energy or matter. Many controlled lab experiments are this type and are rare
in nature.
- Close systemthey have transfers of energy both into and beyond the system boundary but not
transfer of matter.
- Open systemthese are where matter and energy can be transferred from the system across the
boundary into the surrounding environment, most ecosystems are these.
Dynamic When there is a balance between inputs and outputs the system is in dynamic equilibrium. But if one
Equilibrium of the elements of the system changes, like the inputs increase without any corresponding change In
the outputs then the stores change and the equilibrium is unequal. This is called feedback.
Explain the - Dynamic equilibrium refers to the tendency towards a natural state of balance within the
concept of hydrological cycle.
dynamic - The cycle is a closed system as no water enters or leaves the system; it is simply recycled around
equilibrium in the system.
relation to the - The drainage basin element of the hydrological cycle is an open system where the inputs and
water cycle outputs can change.
- The dynamic equilibrium is easily upset by extreme events such as storms or droughts.
- Human activity can also cause disruption to the dynamic equilibrium, eg by modifying the drainage
basin.
- This causes disruption or interference to the dynamic equilibrium and is evidenced through
flooding for example.
- Such events and processes cause sudden changes in the state of the system and disrupt or
interfere with dynamic equilibrium as is the case with flooding.
Positive Where the effects of an action are amplified by subsequent knock-
feedback on secondary effects.
Negative Where the effects of an action are nullified by the subsequent
feedback knock on effects.
Study of Earth The earth can be studied using a systems approach. The earth as a whole is considered a closed
as a system system. Energy comes into the system in the form of solar energy and is balanced by radiant energy
, loss by Earth.
At the global level the earth has 4 major subsystems:
- Atmosphere
- Lithosphere
- Hydrosphere
- Biosphere
Each can be considered an open system that forms part of a chain a cascading system.
key terms
Flow/transfer a form of linkage between one store/component and another that involves movement of energy or
mass.
Inputthe addition of matter/energy into a system.
Storea part of the system where energy/mass is stored or transformed
Systema set of interrelated components working together towards some kind of process.
1.2 The water cycle
Water on All water:
Planet earth - 97% sea water
- 3% fresh water
Fresh water:
- 79% Ice caps and glaciers
- 20% ground water
- 1% easily accessible
Easily accessible water:
- 52% lakes
- 38% soil moisture
- 1% in organisms
- 1% rivers
- 8% Atmospheric water vapour
Water on or close to the earth’s surface is called the hydrosphere.
Total amount of water in hydrosphere is approx.=1.338 * 10 9 KM3
The amount of water in the different stores is in a state of dynamic equilibrium, with changes at a range
of timescales from diurnal to geological.
Oceanic Dominates the amount of available water. Only 5% of the earths water in the oceans has been explored.
Water Ocean water contains dissolved salts. The salts allows the seas to stay a liquid below 0 degrees C. the
seas are alkaline with an average PH of 8.14, the pH is falling and seems destined to continue falling. This
change in the pH is linked to the increase in atmospheric carbon and may have a profound influence on
marine ecosystems.
Cyrospheric Water
Cyrospheric The cryosphere is where the earth’s water is solid. There are 5 locations of cryosphere water:
Water - Sea ice e.g. Ross Ice Shelf
- Permafrost e.g. the Alaska North Slope
- Alpine Glaciers e.g. Mer De Glace, France
- Ice sheets e.g the Greenland Ice sheet
- Ice caps e.g. the Iceland ice cap
Sea ice Much of the Artic Ocean is frozen, this changes during the year due to winter and shrinks in summer. Sea
ice forms when water in the oceans is cooled to temperatures below freezing.
Ice shelves Ice shelves are platforms of ice that form where ice sheets and glaciers move out into the oceans. Ice
shelves exist in Antarctica and Greenland as well as the Artic near Canada and Alaska. Icebergs are
chunks of ice that break off glaciers and ice shelves and drift in the oceans.
Ice sheets an ice sheet is a mass of glacier lamb price extending more than 50,000 KM 2. the two major ice sheets on
the earth today cover most of Greenland an Antarctica. the Antarctic and Greenland ice sheets contain
more than 99% of the freshwater ice on earth extending over 14 million KM 2. areas where snow that falls
, in winter does not melt entirely over the summer, over thousands of years the layers of snow piled up
into thick masses of ice growing thicker and denser as the new snow and ice is compresses the older
layers. sheets are constantly in motion slowly flowing downhill under their own weight. ice sheets
contain enormous quantities of frozen water if the Greenland ice sheet melted scientists estimated that
sea levels would rise about 6 metres and if the Antarctic sheet melted the increase would be 60m.
Ice caps Ice caps are thick layer of ice on land that are smaller than 50,000 KM 2. Usually found in mountainous
regions, they tend to be Dome shaped and ascend over the highest point of an upland area. Ice caps
occur all over the world from the polar regions to mountainous areas such as the Himalayas the rookies
and Andes.
Alpine Alpine glaciers are thick masses of ice found in deep valleys or an upland hollow, most valley glaciers are
glaciers fed by ice from ice cap is smaller corrie glaciers. These are particularly important in the Himalayas where
about 15,000 Himalayan glaciers form a unique reservoir which supports perennial rivers such as the
Indus and Ganges.
Permafrost Permafrost is defined as ground that remains at or below 0 degrees Celsius for at least two consecutive
years. The thickness of permafrost varies from less than one metre to more than 1500 metres, majority
of primer frosts form during cold glacial periods and has persisted through warmer interglacial periods
including the Holocene. Some shallow permafrost formed during the second part of the Holocene and
some during the little Ice Age. Subsea permafrost occurs at close to zero degrees Celsius over large areas
of the Arctic continental shelf where at his form during the last glacial period on the exposed shelf
landscapes when sea levels were lower. The permafrost has begun to melt as climate warms, second
thing large amounts of carbon dioxide and methane affecting global climates.
Explain the - Cyrospheric change has a regulatory role in sea levels.
role of - The cryosphere is a major store of water.
Cyrospheric - In a period of cooling (glacial period) the cryosphere will grow in size.
change in the - This is because the water cycle is slowed considerably as the ice restricts the return of the water to
water cycle the sea and ocean.
- In a period of warming the cryosphere will add water to the cycle.
- As the water cycle restarts more of the ice melts and returns water to the sea.
- This increased the size of ocean store causing sea levels to rise through increased volumes of water
and thermal expansion.
- Consideration of changes in permafrost is also valid.
Terrestrial water
Surface Surface water is the free-flowing water of rivers as well as the water of ponds and lakes.
water Rivers:
- rivers act as both store and a transfer of water, they are streams of water within a defined channel.
- rivers transfer water from the ground from soils an from atmosphere to the store.
- this store could be wetland lakes or the oceans.
- rivers make up only a small percentage of all water, the worlds largest river is the Amazon in South
America averaging a discharge of about 209,000 metres3/s, this is greater than the largest 7
independent rivers combined.
Lakes:
- lakes are collections of freshwater found in hollows on the land surface.
- they are generally deemed a lake if they are greater than two hectares in area.
- The majority of lakes on earth are freshwater and mostly in the northern hemisphere at higher
latitudes, Canada has an estimated 31,752 lakes larger than three KM 2 And an estimated total
number of 2,000,000.
- the largest lake is the Caspian Sea at 78,200 KM 3, which tends to be fresh water although is saline in
some areas.
Wetlands:
- the Ramsar convention defines wetlands as areas of marsh, fen, peat land or water, whether natural
or artificial, permanent or temporary, with water that is static or flowing where there is dominance
by vegetation.
- there are areas where water covers the soil or is present either at or near the surface of the soil all
year or for varying periods of time during the year including during the growing season.
- water saturation determines how the soil develops in the types of plants and animal communities
living in or on the soil.
Water and carbon cycles
1.1 Systems frameworks and their application
System A system is an assemblage of interrelated parts that work together by way of some driving process.
They are a series of stores/components that have flows or connections between them.
Elements are the things that make up a system of interest, attributes are the perceived characteristics
of the elements and relationships are descriptions of how the various elements work together to carry
out some kind of process.
Common - They have a structure that lies within a boundary.
characteristics - They are generalisations of reality, removing incidental detail that obscures fundamental
of a system relationships.
- They function by having inputs and outputs of material that is processed within the components
causing it to change in some way.
- They involve flows of material between components.
Classification - Isolated systemsthey have no interactions with anything outside the system boundary. There is
of systems no input or output of energy or matter. Many controlled lab experiments are this type and are rare
in nature.
- Close systemthey have transfers of energy both into and beyond the system boundary but not
transfer of matter.
- Open systemthese are where matter and energy can be transferred from the system across the
boundary into the surrounding environment, most ecosystems are these.
Dynamic When there is a balance between inputs and outputs the system is in dynamic equilibrium. But if one
Equilibrium of the elements of the system changes, like the inputs increase without any corresponding change In
the outputs then the stores change and the equilibrium is unequal. This is called feedback.
Explain the - Dynamic equilibrium refers to the tendency towards a natural state of balance within the
concept of hydrological cycle.
dynamic - The cycle is a closed system as no water enters or leaves the system; it is simply recycled around
equilibrium in the system.
relation to the - The drainage basin element of the hydrological cycle is an open system where the inputs and
water cycle outputs can change.
- The dynamic equilibrium is easily upset by extreme events such as storms or droughts.
- Human activity can also cause disruption to the dynamic equilibrium, eg by modifying the drainage
basin.
- This causes disruption or interference to the dynamic equilibrium and is evidenced through
flooding for example.
- Such events and processes cause sudden changes in the state of the system and disrupt or
interfere with dynamic equilibrium as is the case with flooding.
Positive Where the effects of an action are amplified by subsequent knock-
feedback on secondary effects.
Negative Where the effects of an action are nullified by the subsequent
feedback knock on effects.
Study of Earth The earth can be studied using a systems approach. The earth as a whole is considered a closed
as a system system. Energy comes into the system in the form of solar energy and is balanced by radiant energy
, loss by Earth.
At the global level the earth has 4 major subsystems:
- Atmosphere
- Lithosphere
- Hydrosphere
- Biosphere
Each can be considered an open system that forms part of a chain a cascading system.
key terms
Flow/transfer a form of linkage between one store/component and another that involves movement of energy or
mass.
Inputthe addition of matter/energy into a system.
Storea part of the system where energy/mass is stored or transformed
Systema set of interrelated components working together towards some kind of process.
1.2 The water cycle
Water on All water:
Planet earth - 97% sea water
- 3% fresh water
Fresh water:
- 79% Ice caps and glaciers
- 20% ground water
- 1% easily accessible
Easily accessible water:
- 52% lakes
- 38% soil moisture
- 1% in organisms
- 1% rivers
- 8% Atmospheric water vapour
Water on or close to the earth’s surface is called the hydrosphere.
Total amount of water in hydrosphere is approx.=1.338 * 10 9 KM3
The amount of water in the different stores is in a state of dynamic equilibrium, with changes at a range
of timescales from diurnal to geological.
Oceanic Dominates the amount of available water. Only 5% of the earths water in the oceans has been explored.
Water Ocean water contains dissolved salts. The salts allows the seas to stay a liquid below 0 degrees C. the
seas are alkaline with an average PH of 8.14, the pH is falling and seems destined to continue falling. This
change in the pH is linked to the increase in atmospheric carbon and may have a profound influence on
marine ecosystems.
Cyrospheric Water
Cyrospheric The cryosphere is where the earth’s water is solid. There are 5 locations of cryosphere water:
Water - Sea ice e.g. Ross Ice Shelf
- Permafrost e.g. the Alaska North Slope
- Alpine Glaciers e.g. Mer De Glace, France
- Ice sheets e.g the Greenland Ice sheet
- Ice caps e.g. the Iceland ice cap
Sea ice Much of the Artic Ocean is frozen, this changes during the year due to winter and shrinks in summer. Sea
ice forms when water in the oceans is cooled to temperatures below freezing.
Ice shelves Ice shelves are platforms of ice that form where ice sheets and glaciers move out into the oceans. Ice
shelves exist in Antarctica and Greenland as well as the Artic near Canada and Alaska. Icebergs are
chunks of ice that break off glaciers and ice shelves and drift in the oceans.
Ice sheets an ice sheet is a mass of glacier lamb price extending more than 50,000 KM 2. the two major ice sheets on
the earth today cover most of Greenland an Antarctica. the Antarctic and Greenland ice sheets contain
more than 99% of the freshwater ice on earth extending over 14 million KM 2. areas where snow that falls
, in winter does not melt entirely over the summer, over thousands of years the layers of snow piled up
into thick masses of ice growing thicker and denser as the new snow and ice is compresses the older
layers. sheets are constantly in motion slowly flowing downhill under their own weight. ice sheets
contain enormous quantities of frozen water if the Greenland ice sheet melted scientists estimated that
sea levels would rise about 6 metres and if the Antarctic sheet melted the increase would be 60m.
Ice caps Ice caps are thick layer of ice on land that are smaller than 50,000 KM 2. Usually found in mountainous
regions, they tend to be Dome shaped and ascend over the highest point of an upland area. Ice caps
occur all over the world from the polar regions to mountainous areas such as the Himalayas the rookies
and Andes.
Alpine Alpine glaciers are thick masses of ice found in deep valleys or an upland hollow, most valley glaciers are
glaciers fed by ice from ice cap is smaller corrie glaciers. These are particularly important in the Himalayas where
about 15,000 Himalayan glaciers form a unique reservoir which supports perennial rivers such as the
Indus and Ganges.
Permafrost Permafrost is defined as ground that remains at or below 0 degrees Celsius for at least two consecutive
years. The thickness of permafrost varies from less than one metre to more than 1500 metres, majority
of primer frosts form during cold glacial periods and has persisted through warmer interglacial periods
including the Holocene. Some shallow permafrost formed during the second part of the Holocene and
some during the little Ice Age. Subsea permafrost occurs at close to zero degrees Celsius over large areas
of the Arctic continental shelf where at his form during the last glacial period on the exposed shelf
landscapes when sea levels were lower. The permafrost has begun to melt as climate warms, second
thing large amounts of carbon dioxide and methane affecting global climates.
Explain the - Cyrospheric change has a regulatory role in sea levels.
role of - The cryosphere is a major store of water.
Cyrospheric - In a period of cooling (glacial period) the cryosphere will grow in size.
change in the - This is because the water cycle is slowed considerably as the ice restricts the return of the water to
water cycle the sea and ocean.
- In a period of warming the cryosphere will add water to the cycle.
- As the water cycle restarts more of the ice melts and returns water to the sea.
- This increased the size of ocean store causing sea levels to rise through increased volumes of water
and thermal expansion.
- Consideration of changes in permafrost is also valid.
Terrestrial water
Surface Surface water is the free-flowing water of rivers as well as the water of ponds and lakes.
water Rivers:
- rivers act as both store and a transfer of water, they are streams of water within a defined channel.
- rivers transfer water from the ground from soils an from atmosphere to the store.
- this store could be wetland lakes or the oceans.
- rivers make up only a small percentage of all water, the worlds largest river is the Amazon in South
America averaging a discharge of about 209,000 metres3/s, this is greater than the largest 7
independent rivers combined.
Lakes:
- lakes are collections of freshwater found in hollows on the land surface.
- they are generally deemed a lake if they are greater than two hectares in area.
- The majority of lakes on earth are freshwater and mostly in the northern hemisphere at higher
latitudes, Canada has an estimated 31,752 lakes larger than three KM 2 And an estimated total
number of 2,000,000.
- the largest lake is the Caspian Sea at 78,200 KM 3, which tends to be fresh water although is saline in
some areas.
Wetlands:
- the Ramsar convention defines wetlands as areas of marsh, fen, peat land or water, whether natural
or artificial, permanent or temporary, with water that is static or flowing where there is dominance
by vegetation.
- there are areas where water covers the soil or is present either at or near the surface of the soil all
year or for varying periods of time during the year including during the growing season.
- water saturation determines how the soil develops in the types of plants and animal communities
living in or on the soil.
