4.1 Water systemsIB Environmental Systems and Societies HL: Flashcards
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What drives movement of water in the hydrosphere?
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- What drives movement of water in the hydrosphere?
- Solar radiation and gravity.
- Percentages for oceans, glaciers, groundwater and surface freshwater?
- Oceans 96.5%, glaciers 1.7%, groundwater 1.7%, surface freshwater 0.02%.
- How did irrigation change the Aral Sea?
- Diverted river inflow so evaporation outputs exceeded inputs and the lake shrank.
- What is a steady state?
- A condition where inputs equal outputs so the store stays constant.
- HL: Name three properties of water that support life.
- Solvent properties, cohesion and adhesion, high specific heat capacity; also ice floats and high buoyancy.
- HL: Why does ice float?
- Water is densest at about 4 °C; ice is less dense than liquid water, so lakes freeze from the top.
- HL: How do the oceans act as a carbon sink?
- They absorb CO2 from the atmosphere and sequester it, as dissolved CO2 and as biomass.
- HL: What causes ocean acidification?
- CO2 dissolves to form carbonic acid, releasing H+ ions and lowering pH.
- HL: How is carbon sequestered in the longer term?
- In biomass that sinks and accumulates on the seabed.
- HL: What is stratification?
- Layering of water with warm water above cold, because density differences restrict mixing.
- HL: What is a thermocline?
- The transition layer between the warm mixed surface layer and cooler water below.
- HL: How does warming affect stratification?
- It increases the intensity of stratification, reducing mixing of oxygen and nutrients.
- HL: What is an upwelling?
- Rising of cold, nutrient-rich water to the surface.
- HL: What drives thermohaline circulation?
- Differences in temperature and salinity, which produce differences in density.
- HL: Why is the ocean conveyor belt important?
- It distributes heat around the world and so affects climate.
Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).