ELSS S1, 3 and 4

• What % of Earth's surface is oceans?

  71%
• How do oceans moderate Earth's environment?

  1. Absorbing heat, storing it and releasing it slowly
  2. Clouds reflect 1/5 of solar radiation - lowers temperature (albedo effect)
  3. Water vapour absorbs long-wave radiation from the Earth - helps maintain global temps 15*C higher than would be
• How do flora use water?

  1. Manufacture own food so need water for: photosynthesis (combining CO2, sunlight & water = glucose and starches); respiration (converts glucose to energy through reaction with oxygen- release CO2 & water)
  2. Maintain rigidity- wilt when run out of water
  3. Transport mineral nutrients from the soil
  4. Cooling- transpiration of water from leaf surface cools plants by evaporation
• How do fauna use water?

  1. Water= the medium for all chemical reactions - i.e. circulation oxygen and nutrients
  2. Evaporative cooling achieved through panting
• How do humans use water?

  1. Water = the medium for all chemical reactions - i.e. circulation of oxygen and nutrients
  2. Cooling - sweating
  3. Economic activity- generate electricity, irrigate crops, provide recreational facilities, satisfy public demand (drinking water, sewage disposal), industry (food manufacturing, brewing, steel making)
• How is carbon stored?

  1. Carbonate rocks (limestone)
  2. Sea floor sediments
  3. Ocean water (as dissolved CO2)
  4. Atmosphere (CO2 gas)
  5. Biosphere
• How is life carbon based?

  Built on large molecules of carbon - proteins, carbohydrates, nucleic acids
• How can carbon be used as an economic resource?

  1. Fossil fuels (coal, oil, natural gas) power the global economy
  2. Oil is used as a raw material in manufacturing of products (from plastics to paint and synthetic fabrics)
  3. Agricultural crops and forest trees store large amounts of carbon available for human use (i.e. food, timber, paper, textiles etc)
• What is the atmosphere?

  Envelope of gases surrounding the planet
• What is the cryosphere?

  Frozen part of the Earth's surface
• What is the lithosphere?

  Rigid outer part of the Earth (upper mantle and crust) - divided into tectonic plates
• What is hydrosphere?

  All the water on the Earth's surface
• What is the biosphere?

  Space at the Earth's surface and within atmosphere occupied by living ogranisms
• What is the pedosphere?

  Soil layer of Earth
• At a global scale, what are the 3 main stores of the water cycle?

  1. Oceans (biggest store)
  2. Atmosphere (smallest store)
  3. Land
• What are the main processes by which water moves between the 3 stores?

  1. Precipitation
  2. Evapotranspiration
  3. Run-off
  4. Groundwater flow (horizontal movement of water within aquifers)
• What is the long-term storage of carbon AND what % does it hold of all carbon on Earth?

  Sedimentary rocks - 99.9%
• What stores does the carbon in circulation move between?

  1. Atmosphere
  2. Oceans
  3. Soil
  4. Biosphere
• What are the main processes by which circling carbon moves between the stores?

  1. Photosynthesis (atmosphere to terrestrial biomass)
  2. Respiration (terrestrial biomass to atmosphere)
  3. Oxidation (human activity- combustion to atmosphere; decomposition- terrestrial biomass to atmosphere; soil to atmosphere)
  4. Weathering (sedimentary rocks to atmosphere)
• What is a large-scale, infrequent event which moves a large amount of carbon from sedimentary rock to the atmosphere?

  Volcanic eruption
• Define systems

  Systems are groups of objects and the relationships that bind the objects together
• What is a closed system?

  A system with inputs and outputs of energy, but without any movement of materials across system boundaries
• What is an open system?

  A type of system whose boundaries are open to both inputs and outputs of energy and matter
• What type of system are the water and carbon cycles at a global scale?

  Closed systems
• Why are the global water and carbon cycles closed?

  Only energy (and not matter) can cross the boundaries of the global water and carbon cycles
• What energy drives the global water and carbon cycles?

  Sun's energy (external to the Earth)
• What type of system are smaller scale water and carbon cycles?

  Open systems
• Examples of smaller scale cycles

  1. Drainage basins
  2. Forest ecosystem
• Why can smaller scale cycles be considered open?

  Materials as well as Sun's energy can cross system boundaries
• What % of global water is stored in oceans?

  97%
• What % of global water is stored in polar ice and glaciers?

  2%
• What % of global water is stored as groundwater (aquifers)?

  0.7%
• What % of global water is stored in the atmosphere?

  0.001%
• How much water is frozen in the ice caps of Antarctica and Greenland?

  3/4
• How much fresh water is stored below ground in permeable rocks?

  Only 1/5 of all fresh water
• What can explain the fact that only a minute fraction of water is found in the atmosphere?

  Rapid flux of water (into and out of the atmosphere)
• What is the avg. residence time of a water molecule in the atmosphere?

  9 days
• How much water does the global water cycle budget circulate per year (estimate) as inputs and outputs between the principal water stores?

  505,000km3
• What are the main inputs and outputs of the water cycle?

  1. Water vapour evaporated from oceans, soils, lakes and rivers
  2. Vapour transpired through the leaves of plants
  3. Precipitation (rain, snow, hail etc)
  4. Condensation (fog)
  5. Ice sheets, snowfields, glaciers release water by ablation (melting & sublimation)
  6. Run-off (drains precipitation & meltwater from land into rivers)- BUT some continental drylands drain to inland basins (i.e. S-W USA)
  7. After infiltrating soil, water may percolate (gravity) into permeable rocks/aquifers- eventually reaches surface (springs & seepages- contribute to run-off)
• What is the biggest stores of carbon AND how much (bn tonnes)?

  Sedimentary (carbonate) rocks (i.e. limestone, chalk) and deep ocean sediments - 60,000 - 100,000,000