2016 Flashcards
(22 cards)
What is biomass’ carbon output
Releases co2 on combustion but the overall use is carbon neutral
What is HEP
Can be used to store gravitational potential energy
What is instream tidal power
Renewable energy that is not solar based
What is an issue with solar energy
The supply is unpredictable
What is hydrogen used for
As a secondary fuel
How do hydrothermal processes produce economically viable metal ore deposits
- hot mineral solutions flow along veins from the batholith
- different minerals have different solubilities
- mineral solutions cool as they move away from the batholith
Why would a reduction in the market price change the cut off grade
Less money is available for extracting and processing so the cut off grade becomes higher for the process to be the most profitable
Why would extra energy be needed if the ore grade decreases
- there will be a greater overburden
- more ore would have to be mined
- less efficient extraction
Why are some windy regions not used as wind farms
- Land use conflicts (urban areas or designated wildlife conservation)
- site problems (access difficulty for construction and maintenance)
How do cfcs deplete stratospheric ozone
- they absorb uv (releasing cl radicals)
- cl reacts with monatomic oxygen
- there is a lack of monatomic oxygen to form ozone (dynamic equilibrium stops and o on concentration drops)
Why is cl concentration higher in the stratosphere towards the poles
Lower temperature allows for the formation of ice crystals
Water treatment method for salty water
- reverse osmosis (high pressure and semi permeable membrane)
- distillation (heated or pressured and the steam is condensed)
How can not eat concentration in water be measured
Colour comparison with an indicator strip
Why are aquifers better than rivers as a water source
- no surface contamination (sewage or pollution)
- no land use conflicts
- lower construction costs
- no short term shortage/ drought
How does unsustainable abstraction cause environmental problems
- reduced water flow/ availability downstream
- loss of breeding sites/ habitats (caused by sedimentation)
- reduced aquifer recharge rates (lowered water table)
- increases concentration of nitrate pollutants (less water dilution)
- changed distribution of species (temperature/ sediment)
Explain why samples are collected at different times in the same location may cause variability
- climatic feature (temperature, rainfall, wind speed and direction, seasonal variations)
- human factors (traffic, pollution)
Standardised variables
- same volume of samples
- same area sampled
- the same (calibrated) equipment
- conducted over the same period of time
Why does contour ploughing reduce soil erosion
- soil ridges reduce water’s flow rate
- the soil is deposited in furrows
Limitations of secchi discs to monitor the turbidity of water
- subjective readings (vary by person)
- water may not be deep enough to obscure sections
- readings are affected by light intensity
How does increased turbidity in tropical rivers affect the ecological processes of coral reefs
- reduced light levels for photosynthesis
- sediments clog the cillia
- sediments damage polyp guts
Why are satellite surveys reliable sources of changing ice mass on earth’s surface
- low altitude orbit/ short orbital period
- gravity measurements (gravimeter)
- radar altitude measurements ( from the surface of the ice to the surface of the sea)
- GRACE by NASA
Why is it difficult to actually predict the future changes to the amount of ice on land
- lack of accurate past data (ice cores aren’t available everywhere)
- negative feedback mechanisms (ice albedo, low cloud cover albedo, natural co2 sequestration)
- positive feedback mechanisms (melting permafrost, increased forest/peat fires, organic matter decay)
- lack of understanding of factors of natural process (temp, precipitation, wind direction and velocity)
- interconnected spheres (bio, atmo, bio)
- time delay between cause and effect
- human changes for the future ( ghg emissions, carbon sequestration, Geo engineering)
