Water

Question 1

How much water circulates annually through the hydrosphere?

Answer 1

• 40,000km3

- Greatest circulation of mass on earth

Question 2

What is water circulation driven by?

Answer 2

• Solar energy

Question 3

Why is the hydrological cycle important?

Answer 3

• Framework by which all other biochemical cycles function

- Supply distribution and dynamics determine pattern, diversity and form of all life

Question 4

What are the human impacts of the water cycle?

Answer 4

• Humans use 50% of all freshwater - increase to 70% by 2050
• Manipulates more than any other resource
• impacts of land use and landscape

Question 5

What are drainage canals?

Answer 5

• They reduce natural flows over a system

- Water is removed from canal

Question 6

How does land use effect water cycle?

Answer 6

• Land use results in changes to the quality, quantity, timing and location of water resources

Question 7

How is the water cycle effected by climate change?

Answer 7

• Climate warming increases the amount of water vapour in atmosphere
• Water vapour is powerful GHG

Question 8

What is the total volume of water on earth?

Answer 8

• 1.4 - 1.5 billion km3

- Volume is fixed and finite

Question 9

How much of earths water is fresh?

Answer 9

• 2.5%
• Majority as ice - 68.6%
• 30.1% groundwater

Question 10

How much of earths water is saline?

Answer 10

• 96.5%

Question 11

What are the hydrological processes and flows?

Answer 11

• Precipitation
• Evaporation - controlled by temp
• Transpiration - loss of moisture through plants from roots
• Sublimation - transition from solid to gas without passing through liquid
• Run off/out

Question 12

How to calculate runoff of global water balance?

Answer 12

Storage = precipitation - evaporation = global runoff

Question 13

Outline seasonal variation in global runoff

Answer 13

• Arctic run off - low in winer and high in summer following thaw
• Seasonal increases - monsoon in SE Asia
• Less variability in temperate regions

Question 14

What is the chemical composition of rain water?

Answer 14

• Low concentration of total controlled solutes
• NaCl (coastal)
• Sulphur and Nitrogen compounds (urban)
• Aerobic - oxygenated, pure water

Question 15

Describe initial infiltration

Answer 15

• Dissolution of CO2 from soil, atmosphere and consumption of oxygen by soil bacteria
• Low total dissolved solids
• Soluble compounds from weathering

Question 16

What is water like in lowland catchment river?

Answer 16

• Increase in total dissolved solutes, organic carbon
• More alkaline
• Increase in contaminants from agriculture in low land locations
• Drop in metal concentrations

Question 17

Describe river water chemistry

Answer 17

• Abundance of chemical species in river water reflects abundance of elements in earths crust and mineral solubility
• Si, al and Fe are most abundant elements

Question 18

How does water change from catchment to coast?

Answer 18

• River water consumption changes
• Longer contact time with stream sediments and river bed
• Increasing number of tributaries with different geology
• Chemical transformations as river and sea water mix
• Constituents generated in river are re diluted in sea water

Question 19

why is the ocean salty?

Answer 19

• Solutes derived from chemical weathering are carried by river into the oceans
• but there is a solubility limit