1. How important are water and carbon to life on Earth?
1.a. Water and carbon support life on Earth and move between the land, oceans,
and atmosphere
Importance of Water:
o We have water due to the goldilocks zone.
o Mars with ice and liquid water means could be life.
o Oceans (71% surface) absorb heat, store and release slowly.
o Clouds reflect a fifth of radiation.
o Water vapour absorbs long wave radiation to maintain global
temperatures to almost 15 degrees higher.
o Essential for all forms of life – major component of cells (60–90% of
organism mass).
o Medium for biochemical reactions (e.g., digestion, respiration).
o To cool: sweat, panting, transpiration.
o Used in (economic activity) agriculture, industry, and domestic settings.
o Supports ecosystems via habitats (e.g., wetlands, rivers).
Importance of Carbon:
o Backbone of organic molecules (proteins, carbohydrates, lipids, DNA).
o Stored in carbonate rocks (limestone), sea floor sediment, oceans,
atmosphere, and biosphere.
o Present in CO₂, which is used in photosynthesis – essential for plant
life and oxygen production.
o Carbon-based fossil fuels (coal, oil, natural gas) are crucial energy
sources.
o Oil for plastics.
o Plants store for humans to use as food, timber, paper, textiles.
Movement Between Spheres (Cycles):
o The cycles are closed systems (driven by the sun) but smaller scales
are open.
o Water molecules and carbon atoms circulating take from a few days to
millions of years
, o Oceans are the biggest store of water and atmosphere is lowest
o Sedimentary rock stores 99.9 of all carbon, the carbon in circulation
moves rapidly.
o Involves exchanges between lithosphere, hydrosphere, atmosphere,
and biosphere.
1.b. The carbon and water cycles are systems with inputs, outputs, and stores
Major Stores:
o Water cycle: atmosphere, oceans, rivers/lakes, cryosphere, soil
moisture, vegetation, groundwater.
o Carbon cycle: atmosphere, terrestrial biosphere (plants, soil), oceans
(dissolved CO₂, marine life), sediments/fossil fuels, carbonate rocks
(biggest store, limestone chalk).
Water Cycle Inputs/Outputs:
o Outputs: precipitation, ablation (melting snow/ice), condensation,
sublimation.
o Inputs: evapotranspiration, runoff, infiltration.
Carbon Cycle Inputs/Outputs:
o Fast cycle: between atmosphere, ocean, biosphere (10x faster). Land
plants are a key part (photosynthesis, respiration, decomposition).
Carbon exchange between oceans and atmosphere (ventilating and
dissolving) this takes 350 years.
o Slow cycle: stored in sea floor sediments and fossil fuels for millions of
years 10- 100 million tones per year. Marine organisms make shells by
CaCO3, on death these sink and become carbon rich rocks for 150
million years until chemical weathering and becomes atmosphere and
water. On land it forms carbonaceous rocks for millions of years.
o Inputs: precipitation (dissolved CO₂ in rain), photosynthesis (CO₂
uptake).
o Outputs: respiration (CO₂ release), decomposition, combustion (natural
and fossil fuels), chemical weathering (e.g., carbonation of limestone).
1.c. The carbon and water cycles have distinctive processes and pathways
Water Cycle Processes
o The water cycle is a closed system of continuous water movement
between the atmosphere, land, and oceans. A key concept is the water
balance, expressed as:
, Precipitation = Evapotranspiration + Streamflow ± Storage
This equation summarises the inputs, outputs, and changes in water
storage within a drainage basin.
o Flows and Transfers
Precipitation occurs when water vapour cools to its dew point
and condenses into droplets. When droplets aggregate and
reach a critical size, they fall. Precipitation intensity affects
runoff:
High intensity (>10–15 mm/hr) can exceed infiltration
capacity, causing overland flow.
Prolonged rainfall, often linked to depressions and frontal
systems, can lead to saturation and flooding.
Snow introduces a time lag between precipitation and
runoff, delaying flow.
Transpiration is the loss of water vapour from plant stomata,
contributing to atmospheric moisture.
Condensation is when water vapour cools and turns into liquid. It
plays a key role in cloud formation:
Cumuliform clouds: Develop vertically due to convection,
where warm air rises, cools, and condenses.
Stratiform clouds: Form through advection, when warm
air moves horizontally over a cooler surface.
Cirrus clouds: High-level, composed of ice crystals, do
not produce precipitation.
Fog and dew: Form near the ground through direct
condensation.
Cloud Formation depends on different lifting mechanisms
and lapse rates:
Environmental lapse rate (ELR) – average decrease of
temperature with height.
Dry adiabatic lapse rate (DALR) – cooling of unsaturated
air as it rises.
Saturated adiabatic lapse rate (SALR) – cooling rate of
saturated air.
o Catchment Hydrology
Includes evaporation, interception (by vegetation), infiltration
(entry into soil), throughflow, groundwater flow, surface runoff,
and cryospheric processes (e.g., snowmelt, glacier flow).
Carbon Cycle Processes
o The carbon cycle involves the movement of carbon between the
atmosphere, biosphere, hydrosphere, and lithosphere. It includes both
slow and fast components.
o Carbon Exchanges
1.a. Water and carbon support life on Earth and move between the land, oceans,
and atmosphere
Importance of Water:
o We have water due to the goldilocks zone.
o Mars with ice and liquid water means could be life.
o Oceans (71% surface) absorb heat, store and release slowly.
o Clouds reflect a fifth of radiation.
o Water vapour absorbs long wave radiation to maintain global
temperatures to almost 15 degrees higher.
o Essential for all forms of life – major component of cells (60–90% of
organism mass).
o Medium for biochemical reactions (e.g., digestion, respiration).
o To cool: sweat, panting, transpiration.
o Used in (economic activity) agriculture, industry, and domestic settings.
o Supports ecosystems via habitats (e.g., wetlands, rivers).
Importance of Carbon:
o Backbone of organic molecules (proteins, carbohydrates, lipids, DNA).
o Stored in carbonate rocks (limestone), sea floor sediment, oceans,
atmosphere, and biosphere.
o Present in CO₂, which is used in photosynthesis – essential for plant
life and oxygen production.
o Carbon-based fossil fuels (coal, oil, natural gas) are crucial energy
sources.
o Oil for plastics.
o Plants store for humans to use as food, timber, paper, textiles.
Movement Between Spheres (Cycles):
o The cycles are closed systems (driven by the sun) but smaller scales
are open.
o Water molecules and carbon atoms circulating take from a few days to
millions of years
, o Oceans are the biggest store of water and atmosphere is lowest
o Sedimentary rock stores 99.9 of all carbon, the carbon in circulation
moves rapidly.
o Involves exchanges between lithosphere, hydrosphere, atmosphere,
and biosphere.
1.b. The carbon and water cycles are systems with inputs, outputs, and stores
Major Stores:
o Water cycle: atmosphere, oceans, rivers/lakes, cryosphere, soil
moisture, vegetation, groundwater.
o Carbon cycle: atmosphere, terrestrial biosphere (plants, soil), oceans
(dissolved CO₂, marine life), sediments/fossil fuels, carbonate rocks
(biggest store, limestone chalk).
Water Cycle Inputs/Outputs:
o Outputs: precipitation, ablation (melting snow/ice), condensation,
sublimation.
o Inputs: evapotranspiration, runoff, infiltration.
Carbon Cycle Inputs/Outputs:
o Fast cycle: between atmosphere, ocean, biosphere (10x faster). Land
plants are a key part (photosynthesis, respiration, decomposition).
Carbon exchange between oceans and atmosphere (ventilating and
dissolving) this takes 350 years.
o Slow cycle: stored in sea floor sediments and fossil fuels for millions of
years 10- 100 million tones per year. Marine organisms make shells by
CaCO3, on death these sink and become carbon rich rocks for 150
million years until chemical weathering and becomes atmosphere and
water. On land it forms carbonaceous rocks for millions of years.
o Inputs: precipitation (dissolved CO₂ in rain), photosynthesis (CO₂
uptake).
o Outputs: respiration (CO₂ release), decomposition, combustion (natural
and fossil fuels), chemical weathering (e.g., carbonation of limestone).
1.c. The carbon and water cycles have distinctive processes and pathways
Water Cycle Processes
o The water cycle is a closed system of continuous water movement
between the atmosphere, land, and oceans. A key concept is the water
balance, expressed as:
, Precipitation = Evapotranspiration + Streamflow ± Storage
This equation summarises the inputs, outputs, and changes in water
storage within a drainage basin.
o Flows and Transfers
Precipitation occurs when water vapour cools to its dew point
and condenses into droplets. When droplets aggregate and
reach a critical size, they fall. Precipitation intensity affects
runoff:
High intensity (>10–15 mm/hr) can exceed infiltration
capacity, causing overland flow.
Prolonged rainfall, often linked to depressions and frontal
systems, can lead to saturation and flooding.
Snow introduces a time lag between precipitation and
runoff, delaying flow.
Transpiration is the loss of water vapour from plant stomata,
contributing to atmospheric moisture.
Condensation is when water vapour cools and turns into liquid. It
plays a key role in cloud formation:
Cumuliform clouds: Develop vertically due to convection,
where warm air rises, cools, and condenses.
Stratiform clouds: Form through advection, when warm
air moves horizontally over a cooler surface.
Cirrus clouds: High-level, composed of ice crystals, do
not produce precipitation.
Fog and dew: Form near the ground through direct
condensation.
Cloud Formation depends on different lifting mechanisms
and lapse rates:
Environmental lapse rate (ELR) – average decrease of
temperature with height.
Dry adiabatic lapse rate (DALR) – cooling of unsaturated
air as it rises.
Saturated adiabatic lapse rate (SALR) – cooling rate of
saturated air.
o Catchment Hydrology
Includes evaporation, interception (by vegetation), infiltration
(entry into soil), throughflow, groundwater flow, surface runoff,
and cryospheric processes (e.g., snowmelt, glacier flow).
Carbon Cycle Processes
o The carbon cycle involves the movement of carbon between the
atmosphere, biosphere, hydrosphere, and lithosphere. It includes both
slow and fast components.
o Carbon Exchanges
