Earths life support systems

• Importance of water for life

  Photosynthesis provides the energy animals need for life

  Reflects terrestrial radiation adding to the greenhouse effect that keeps the planet warm for life.

  Allows for homeostasis

  transpiration cools plants and keeps water in the xylem (transports minerals)

  Necessary for metabolic functions
• Importance of carbon for life

  Forms 95% of all known compounds

  Life building blocks like protein are made of carbon

  Major component of greenhouse gases

  Used to photosynthesis and create glucose.
• Carbon is an element that can bond with lots of different atoms to create complex molecules.
• Carbon can make bonds with up to 4 other atoms simultaneously including other carbon atoms which can form very long polymer bonds.
• water stores

  oceans= 97% and has a residence time of 36,000

  ice= 2% and has a residence time of 15,000

  groundwater=0.7% and has a residence time of 10,000
• Water stores are not evenly distributed as less than 10 countries possess 60% of the worlds available supply
• Evaporation

  Phase change of water to water vapour. Mainflow of water into the atmosphere. Heat breaks the bonds between water molecules and storing it as latent heat. Allows the movement of both water and heat across the globe
• Transpiration

  Diffusion of water vapour from stomata to the atmosphere and is responsible for 1% of atmospheres water.
• Factors that influence transpiration

  Temperature, wind speed, water availability, humididty
• Condensation

  phase change of water vapour to water. Air is cooled to it's dew point and must occur around a condensation nuclei onto which water vapour can condense.
• Condensation Nuclei

  Dust, soot and need at least 1, silver nitrate used to make clouds .
• Cloud formation

  Convection, relief, cold frontal and warm frontal.
• Homogenous Nucleation

  Insolation causes air to rise. The ground releases heat warming air above it. Warmer air is less dense so becomes unstable. Air parcels rise and expand due to low pressure. The air parcel causes air to become cooler. At dew point condensation occurs. WAter vapour turns to water droplets.
• Cumulus Nimbus

  formed when latent heat is released and provides energy to keep saturated air rising
• Environmental lapse rate= Actual change in temperature of the air
• Adiabatic lapse rate= rate at which a non-saturated air parcel cools as it rises
• Saturated Adiabatic lapse= the rate at which a saturated air parcel cools as it rises, condensation occurs due to saturation
• Precipitation

  deposition of water in any form from the atmosphere to the ground
• Factors that influence precipitation

  Intensity, duration, form, seasonality,
• Why do some parts of England have more rain

  60 latitude

  landscape leads to relief rain

  South westerly rain
• Precipitation causation

  Spill moisture as droplets collide and reach a critical mass so causes warm air to rise
• interception

  store of water taken from precipitation. The water is passed on as a flow in the form of evaporation, through fall and stem flow
• Ablation

  removal of water from ice through melting, evaporation, sublimation.

  No liquid phase as multiple particles are needed to be a liquid. Water can additionally leave ice through calving
• Run off

  Occurs when the rainfall intensity exceeds the infiltration capacity. Saturation overland flow is when soil can no longer absorb water, water table rises and causes overland flow.
• Drought

  less precipitation leads to less infiltration and other flows of hydrology. River discharge decreases because the water table drops
• Direct human management of water resources

  If straightening rivers quickens river water table drops. Soil becomes less saturated more easy for infiltration.
• Drainage density

  More rivers means less saturation of lithosphere as flows take water to rivers quickly.
• drainage basin

  Steep slopes prevent infiltration therefore preventing ground flows forcing surface run off
• Vegetation cover

  More water stored in trees means less infiltration
• Soil moisture

  Saturated soils leads to surface run off and unsaturated allows for infiltration, bone-dry soils leads to less
• Geology and soil type

  Impermeable rocks prevent ground flow
• Fast carbon cycle= up to 1000 times as fast as the slow cycle. Respiration, photosynthesis, decomposition and diffusion are the key components
• Slow carbon cycle= calcium carbonate from organisms is stored in rocks beneath oceans. Rocks are weathered and carbon returned to cycle or subduction.
• Industrial processes

  Releases CO2 and Methane. Other than burning fossils fuels, cement production releases the most carbon
• Sedimentation

  Particles held in suspension are deposited on the ocean floor. Plankton shells, coral, bodies, deposited an ocean most bodies dissolve. Each new layer compresses into sedimentary rock.
• Deforestation

  removes a sink of carbon and removal through photosynthesis. Land use change prevents soil acting as a sink
• Re-vegetation

  More photosynthesis and more removal of carbon so there is more storage in the biosphere
• precipitation

  Co2 in the atmosphere dissolves in rainwater to form carbonic acid. Rises from anthropogenic emissions
• Photosynthesis

  Carbon to land plant and plankton via photosynthesis averages around 120 GGT a year. Using the sun's energy and Co2 water, green plants and marine life convert to light to chemical energy.
• Weathering

  Mainly involves rainwater which contains acid rain. Slowly dissolves limestone and chalk through carbonation. Decaying material combines with rainwater which forms humid acid that attack rock minerals