Environmental Science

Environmental Science

1. Paper 2

   • Living Environment
     • Conditions for life on Earth
       • Development of Life
         • Liquid Water
           • All living beings require water for survival: Solvent Water (chemical reactions), Transport, Temp control, High specific heat capacity (helps moderate the rate and range of temp change), Habitats, Absorption of UV.
         • Temp Range
           • Warm enough to have water but not hot enough to denature enzymes
         • Atmospheric gases
           • CO2 for PHS and Nitrogen for protein synthesis
         • Solar insolation
           • Energy for PHS, heat from sun drives hydrological cycle.
       • Conditions for life on Earth
         • Mass
           • The earth has the optimum amount of mass that creates a gravitational pull, binding our atmosphere and keeping our orbit in the Goldilocks Zone which creates the optimum temperature for life on earth.
         • Distance from the Sun
           • Our orbit is the Goldilocks Zone creates the optimum temperature for life on Earth. Not too hot or cold.
         • Magnetic Field
           • Protection from solar wind, which could cause genetic mutation or extreme temps.
         • Speed of Rotation
           • Creates day/night cycle allowing for rest and recovery from UV radiation and temp regulation.
         • Axis of Rotation
           • The angle at which the Earth spins Produces seasonal variations.
       • Impact of life on Earth
     • Conservation of biodiversity
       • Importance
       • Human influences
       • Setting Conservation priorities
       • Legal Protection
       • Captive breeding
       • Release programmes
       • Habitat Conservation/management
     • Habitat Case Studies
       • Mangroves
       • Temperate Broadleaf woodland
       • Deep-sea Coral Reefs
       • Tropical Coral Reefs
       • Antarctica
       • Tropical Rainforest
       • Oceanic Islands
   • Biological Resources
     • Agriculture
     • Forestry
     • Aquaculture
       • Principles
       • Env Imps
       • Extensive VS Intensive
       • Fishing VS Aquaculture
     • Fishing
   • Sustainability
     • Reducing Waste
     • Reducing Pollution
       • CO2
       • NH4
       • NOx
       • SO2
       • Decreasing Fossil fuel use
       • Decreasing mineral extraction
     • Future Generations
     • Long term resources
     • Maintaining Biodiversity
     • Maintaining DE of Biogeochemical cycles
       • Nitrogen Cycle
       • Phosphorous Cycle
       • Carbon Cycle
       • DE of Soil
     • Maintaining DE of Hydrological Cycle
     • Decreasing Carbon Footprint
       • The amount of carbon emissions our actions have
     • Increasing Renewable energy use

2. Paper 1

   • Physical Environment
     • The Atmosphere
       • Atm Struc
         • Dynamic Equilibrium: Moving natural balance. In atm, it is the balance between photosynthesis and aerobic respiration.
         • Atm composition and its importance
           • Contains N2, O2, Co2, H2O. These are needed to make bio molecules for living orgs.
           • Absorption of EM radiation from sun
             • Upper atm prevents most of the damaging solar wind from reaching Earth, most of the UV that passes through is absorbed by the Ozone.
           • Naturally occurring gases in the atm, absorbs the reflected LWIR radiation from the Earth's surface from leaving causing natural warming of the Earth.
             • The heat is distributed over the Earth's surface by wind causing the poles to be cool and tropics to be warm
           • Atm pressure controls water evaporation allowing for liquid water to be present on Earth.
       • Greenhouse effect
         • Natural GH effect
           • natural processes that warms the troposphere
           • GHGs are better at absorbing LWIR than average gases. E.g. CO2
         • Enhanced GH effect
           • Anthropogenically enhanced
           • GHGs
             • CO2: GWP of 1
             • Methane (CH4) : GWP of 25
             • NOx : GWP of 160
           • Global Climate Change
             • Consequences
               • Ecological Changes
                 • Abiotic changes go beyond the range of species' tolerance. E.g. Sea Acidification » Coral Bleaching
                 • Change the survivability of certain species, e.g. oak trees have deep roots and thus are more drought resistant, warmer temps cause plants to grow faster
                 • Timing of ecological events may change, like nesting or migration, due to changing temperatures so survival of interdependent speies may decrease. like pollinators being early or late and maybe missing flowering season.
               • Climatic Process changes
                 • Wind pattern changes: warmer temps near poles lowers the difference between temperature nearer the equator, this means that storms can travel to higher latitudes and storms may last longer due to maintained temps and humidity.
                 • Changes in rainfall: Increase in temp causes increased evap, meaning there is will be more precipitation. Rainfall may last longer and be more heavy meaning there is an increase threat of flooding inland.
                 • El Nino
                   • Occurs every 2-7 years, although seems to be more frequent now.
                   • Normally, trade winds blow Westwards, causing a strong ocean current between the South American West Coast » Australian East Coast, carrying water upwelled in SAWC (full of nutrients from ocean bed), which warms as it moves. This warm water causes heavy rainfall in AEC and droughts (deserts) in SAWC
                   • During El Nino year, the normal is reversed and amplified, causing extreme AEC droughts and SAWC floods. GCC may further amplify this effect.
                 • La Nina
                   • Occurs when winds blow stronger towards the normal direction, causing faster currents and increased temperature differences between East and West.
             • Mitigation methods
             • Adaptation
             • Impacts on the cryosphere
             • Impacts on the ocean
             • Monitoring and predicting
             • Carbon Footprint
         • Positive feedback cycle
           • Causes enhance the effects which in return enhance the causes, never-ending cycle
         • Negative feedback cycle
           • The effect slows or stops the cause, leading to dynamic equilibrium
     • The Hydrosphere
       • Human uses for water (and % of total usage): Agriculture 70% (irrigation), Industry 22% (cooling, heating, washing, solvent), Domestic 8% (flushing, washing, hygiene, thirst).
       • Global demand
         • Increase in population: Birth rate higher than the death rate, or migration.
         • Increase in per-capita use with increased affluence: Poor people manage their water more meticulously as it is a limited but essential resource, affluent people disregard the importance of water.
         • Increased irrigation of farmland: More people means greater demand for food, therefore larger farms that demand irrigation for full efficiency.
         • Industrialisation: Different water requirements for industries. More industries or ones of the same means more water use
       • Human impacts on the hydrological cycle
         • Deforestation: loss of trees can cause a decrease in precipitation in downwind areas as more water infiltrates the soil or runs off into the soil.
         • Agriculture: Soil can be compacted by heavy machinery, decreasing infiltration, meaning reduced soil moisture and runoff increases (flood risk). Crop irrigation increases evaporation. Loss of soil biota (detritivores- worms) reduces infiltration, increases runoff and decreases soil water retention.
         • Urban development: Impermeable surfaces (tarmac, concrete) reducing infiltration, increasing runoff.
         • Global Climate Change: Higher temps affect the rate of ice melting, evap, condensation and wind patterns. These combine to alter the pattern, length and strength of precipitation. Rapid snow and ice melt causes rising sea levels, dilution of salt water, inbalancing the great ocean conveyor belt and thus temp regulation.
       • Sustainable Management of Water Resources
         • Reservoirs
           • Artificial recharge during seasons of surplus water
         • Rivers
         • Lakes
         • Aquifers
           • Artificial Aquifer recharge
             • Pumping water directly into the aquifer to refill it
               • Surplus water is used from seasons of high rainfall, so it helps prevent floods as well
                 • Meets DE, for high demand like summer
         • Habitat Conservation
           • Forests
             • Reduced soil erosion, Regulation of river flows, reduced runoff, increases moisture and water vapour, and rain downwind
             • Prevents agrochemical runoff
           • Wetlands
             • It increases the local water table and natural filtration system and helps restore aquifers through infiltration and percolation.
         • Xeriscaping
           • having low water-needing plants in your garden, like cactuses or succulents
             • Decreases water demand and so abstraction.
         • Drip irrigation
           • Pipes are used to drip water directly on the stems of crops.
       • Water Treatment
         • 1. Screening: Water runs through large metal screens that catch larger sediments like rubbish, plants or animals
           • 2. Flocculation: Adding chemicals to the water to make suspended particles clump together. These chemicals are known as coagulants e.g. Aluminium sulfate
             • 3. Sedimentation: The clumps are left to settle and then removed to a waste pond.
               • 4. Filtration: The water is passed through various materials like sand, gravel, or granular activated carbon to remove smaller unwanted particles
                 • 5. Disinfection: Water may still contain bacteria, viruses or other microorganisms, so it is treated with enough chlorine to eliminate them but not enough to alter taste or smell.
     • The Lithosphere
       • Mineral Extraction
         • Geological processes that created deposits
           • Igneous Processes
             • Rocks and minerals are created by cooling and hardening magma.
               • Hydrothermal deposition
                 • 1. Igneous intrusions form from magma that cools in the crust. the intrusions produce pressurised superheated water that dissolves minerals from surrounding rocks
                 • 2. Mineral-rich solutions move through fissures away from the igneous batholith, cooling whilst moving and crystallising in order of solubility.
                 • 3. This process deposits ores of tin, copper, silver, gold, etc.
           • Metamorphic Processes
             • Igneous processes and tectonic plate movement can alter existing rock e.g. Limestone into Marble, or Sandstone into Quartzite
           • Sedimentary Processes
             • Minerals settle and then build-up
             • Proterozoic Marine Sediment
               • E.g. Iron ore deposits like haematite or magnetite, formed when dissolved iron compounds became oxidised—occurred mainly mainly between 2.5-and 1.8 bn years ago
             • Alluvial Deposits
               • Materials that were carried and separated by flowing water. this depends on the velocity of the water and the density of the material.
                 • E.g. Gold, diamond, tin, sand
             • Evaporites
               • Water from an isolated ancient sea evaporates leaving crystallised minerals like halite (salt).
             • Biological processes
               • Living organisms form mineral deposits often sedimentary rocks.
                 • E.g. Shells of marine orgs form Limestone and Chalk. Or Terrestrial vegetation forms coal.
         • Exploitation
           • Lasky's Principle
             • As quality of mineral ores decreases, the quantity increases.
               • The problem of the future is how to exploit lower-grade ores
           • Stock: All material that exists in the lithosphere including the exploitable minerals and never exploitable ones.
           • Resource: All minerals that are currently exploitable and theoretically exploitable (with money and tech improvement)
           • Reserve: Exploitable now, with current tech and money
           • Viability issues
             • Purity: Low grade means more needed to be mined, more waste, more energy used, more pollution
             • Chemical Form: Some forms are easier to extract e.g. aluminum from bauxite but not clay
             • Overburden/Hydrology: Removal of overburden uses blasts, loose OB increases risk of landslides so benches are usually at soft gradients.
             • Depth: Opencast - removal of overburden, uses excavators; Deep- mining - +depth = +cost, danger of mine collapse, groundwater and runoff could flood mines and + costs
             • Economic Viability: Income > production cost, COOG lowest purity that can be mined economically
             • Transport Cost: reduce costs = Existing infrastructure, reduced size of mineral being transported, distance travelled for selling
             • Market Economies: Supply VS Demand
         • Exploration
           • Survey Techniques
             • IR Spectroscopy: Different IR Wavelengths belong to different Minerals, helps identify them
             • Gravimetry: Detect variation in gravity caused by variations in density and mass, igneous is usually denser than sedimentary.
             • Magnetometry: detects more magnetic rocks e.g. iron ore magnetite
             • Seismic Surveys: these involve sound waves produced by controlled explosions, echoes give info about the depth, density and shape of rock strata
             • Resistivity: Difficulty with which electricity passes through, sedimentary has lower resistivity than igneous
             • Trial Drilling: Most expensive technique of exploration, only method to produce a sample.
             • Chemical analysis: Lab tests to confirm chemical composition and purity.
         • Environmental impacts
           • Land Take
             • The siting of a mine/quarry is limited to the location of mineral deposits
               • Land is required for infrastructure, processing buildings, overburden/spoil heaps, storage for pumped water.
                 • This often results in conflict with other local land users e.g. agriculture/residents
           • Habitat Loss
             • Forest, grassland clearance, lakes are contaminated or over-pumped.
           • Air pollution
             • From explosions, vehicles like excavators or transport trucks, dust from windblown dust heaps
               • PM, Ash, SO2 -> respiratory problems, plant leaves covered reducing PHS, dust in water courses increasing turbidity
           • Noise pollution
             • Rock blasting, excavation, vehicles create high levels of noise.
               • Disturbs nearby residents, disturbs wildlife around the quarry, disturbs over-flying birds
           • Turbid Drainage Water
             • Loose sediments from excavation, runoff into rivers, creates high TSS
               • Creates turbid conditions: reduces light penetration, reduces primary productivity, reduces aquatic plant PHS Causing deoxygenation and impact on food chain.
           • Waste disposal
             • Stability -- if the spoil is not compacted erosion via wind and rain can occur, causing suspension of dust in air or runoff into rivers
               • Heavy metal leachate, acid mine drainage
         • Future supplies
           • Improvement in exploration techniques
             • Improvement of remote sensor tech e.g. Visible and IR
               • Greater resolution imaging
             • Portable field equipment
               • IR Spectroscopy, radiation detection
             • Smaller/ Lighter equipment, longer lasting batteries
           • Mechanisation
             • Larger, more powerful machines becoming more efficient; use of machines in deep/ hot mines.
           • Improvement in extraction of low-grade ores
             • Phytomining
               • Uses plants to extract valuable metals from soil or waste. Certain plants, called hyperaccumulators, absorb metals like nickel, cobalt, or gold from the ground and store them in their tissues.
             • Bioleaching
               • Use of living organisms to extract metals from their ores, The metal is extracted from the solution formed through bioleaching by​ electrolysis or, using carbon filters
             • Leachate Displacement
               • Rainwater percolating through the spoil heap dissolves copper, we collect the solution, its sprayed back into the heap, more copper dissolves, concentrating the target ore, then is extracted by electrolysis
             • Iron Displacement
               • Iron is more reactive than the copper, iron is added to displace the copper from the copper sulphate solution. Copper can then be extracted as a solid.
             • Rare earth minerals
               • Chemical separation often results in toxic waste.
                 • Bacterial Adsorption: Dissolved ions of rare minerals attach to the surfaces of bacteria. Acids are used to wash off the minerals. different minerals need different pH solutions.
             • Polymer adsorption
               • Metal ions dissolved in seawater will adsorb onto the surface of polymers (e.g. synthetic, lignin (wood), chitin (shrimp shells); used to extract uranium.
           • Exploiting previously inaccessible deposits
             • Polymetallic nodules
               • Manganese nodules; deep (4000m-5000m)
                 • Expensive to exploit due to current level of technology, requires international agreements in order to exploit. extraction can disturb benthic sea life by increasing turbidity.
       • Biogeochemical cycles
         • Nitrogen Cycle
           • Summary
             • Plants: N in protein, amino acids and DNA
               • Animals: N in protein, amino acids and DNA
               • Death: DOM
                 • Ammonification: decomp by detris and bact
                   • Oxidation by bact makes N >NO2
                     • Oxidation by bact makes NO2> NO3
               • Soil
                 • Atmosphere
                   • Nitrogen can't be directly absorbed by plants so there's no direct interaction
                     • The only exception is due to 'legumes', which have nitrogen-fixing bacteria in their root nodules called Rhizobium.
                   • Ionising processes take nitrogen from atm to soil- lightning: N2+O2 > NOx
                   • Nitrogen fixation by bacteria
                 • Denitrifying bacteria return nitrogen from the soil to the atm
               • Root absorption
               • Eaten
         • Phosphorous Cycle
   • Pollution
   • Energy
     • Importance of supply: increased reliance on energy for everyday use. We use it in agriculture to fuel machines, appliances, systems, and lights; we use it in manufacturing for heating, transport and more. It is an extensive industry that is essential for everything now.
     • Features
       • Renewables: Infinite, harvested from natural resources, low env impacts
       • Non-renewables: Fossil-Fuels naturally forms and reforms, but over multiple lifetimes, meaning finite.
       • Abundance: Amount of resources that exist, could be unreachable, unharvestable
       • Constraints: Resource distribution, i.e. deposits of ores or coal, oil, gas.
       • Predictability: Knowing how much energy will be available and whether it will meet demand. Solar is not predictable because of weather factors.
       • Intermittence: Availability of resource (e.g. day/night for solar)
       • Energy density: Measure of energy in a given mass of energy resource. FFs are all energy dense, while solar is not so.
       • Applicability: whether a resource can be utilised in multiple ways of energy. Oil is applicable in multiple ways, through fractional distillation it can be broken down to multiple uses like, kerosene (jet fuel), diesel (car fuel)
       • Ease of storage: FFs are easily storable as they are energy-dense in small amounts. Whereas wind, solar, HEP are hard to store because they need a battery, which we don't have a big enough one.
       • Env impacts: All energy exploitation methods have environmental impacts however they differ in the extent.
     • Current Tech: Sustainability
     • Fossil fuels
       • Future Strategies of extraction
         • Oil sand extraction (in-situ)
           • Disadv: energy intensive, expensive, high water use
           • Steam is pumped down to heat the bitumen to make it flow.
           • Deep deposits can be extracted with removal of overburden
         • Net-Zero
           • No extra carbon emissions
             • To reach this: Renewable energy sources, electric transport, energy conservation, CCaS
         • 2ndary and 3rdary oil extraction
           • Constant pressure in oil wells means more extracted material.
             • Tertiary: Using constant flow of gas to displace oil, and using heat or bacteria to reduce the viscosity of oil for less energy intensive extraction.
             • Secondary: Uses natural gas
         • Catalytic Converters
           • Gas from combustion in engines is passed through a converter into H2O, N2,CO2.
             • NOx from regular engines has 265x higher GWP than CO2
             • Converter are coated with precious materials e.g. Platinum, palladium and rhodium.
         • CO2- Carbon capture and storage
           • CO2 captured before emitted, pressurised into liquid form, pumped into wells or aquifers.
             • DISADV: V. expensive; high energy requirement to set-up; lack of use; doesn't deal with extraction, processing or transport or other pollutants (NH4, SO2, NOx, PM)
             • ADV: Essential to reach net-zero, according to IPCC
           • British Geological Survey (BGS) : Survey, net-zero, looking for places to artificially sequester carbon
         • Directional Drilling
           • Horizontal drilling tech that uses computers to be directed.
             • DISADV: Still some extraction impacts
             • ADV: Only one drill at a time on the surface (less impact); can be used under sensitive land use with limited disruption to the surface; can extract multiple deposits, less expensive
         • Coal Liquefaction
           • Turning the coal into oil by using solvents directly on the coal in the deposit.
             • DISADV: High energy use and waste contaminants to process
             • ADV: Multiple applications (fractional distillation); extends lifespan of liquid FFs
         • Coal Gasification
           • Turning coal into gas through partial combustion in the chamber/ deposit it is found in by injecting gas. This creates Syngas, which is then extracted.
             • DISADV: Not widely used, Expensive
             • ADV: Avoids habitat destruction (unlike open-cast); deep deposits become viable sources (instead of underground mining); bottom ash is left in the deposit, so no PM is emitted in to atm.
       • Gas
         • Extraction
           • Conventional gas extraction
             • Drilling holes into deposits of rock that have the gas in them (usually shale)
               • Can cause methane leakage - GHG with high GWP (25)
           • Hydraulic Fracturing
             • Forcing water with sand down into cracks and fissures (usually shale) to force gas out. It comes back with water contaminated with sand, heavy metals, chemicals, and natural gas.
               • Requires huge amounts of water, and the process causes small tremors that may cause structural damage and soil instability.
       • Oil
         • Processing
           • High energy use for fractional distillation
             • Different fractions for different uses: e.g. 40-100C for petrol (cars), 150C - 240C for kerosene (jet), Bitumen +350C (asphalt)
         • Extraction
           • Oil Sands
             • Open-cast mining also appropriate
           • Drilled Oil Wells
             • Env Imps:
               • High Energy use
               • Habitat destruction
               • Tech failures causing leakage
       • Coal
         • Disposal: either land fill or a lagoon
         • Highest particulate emission
           • Fly ash, bottom ash
             • Impacts
               • Dissolved heavy metals in water, toxic
               • Erosion of ash pile - increased TSS » increased turbidity in rivers » blocked gills » decreased biodiversity
               • PM in air cover leaves leading to decreased PHS, less forests, carbon sequestration, and temperature regulation
         • Electricity
           • Thermal power station (8 in the UK, cap of 14GW)
             • GHG emissions from combustion: CO2, SO2, NOx
               • SO2 + NOx: Create acid rain which can destroy significantly amounts of habitats
         • Processing
           • Coal Slurry: Tailing ponds of waste water
             • Coal is crushed and washed to eliminate waste, and 30% of coal is left in a slurry.
               • Env imp: Contaminants can easily leach e.g. heavy metals
         • Extraction
           • Open-cast/underground mining
             • Env imps: Habitat destruction, air pollution (dust and GHG emissions), noise pollution (excavators/machines), water pollution (toxic/heavy metals - mercury/arsenic)
     • Renewables
       • Solar
         • Improved technology
           • Biomimetics
           • Self cleaning
           • Types of PV cell
           • Concentrating Solar power
         • Photovoltaic: Solar panels generate electricity
           • Photons hit panel, excite electrons, create flow of electricity. Domestic PV, easy to install.
             • Disadv: Costly
             • Adv: Good for small scale, few env impacts, low maintenance cost.
         • Photothermal
           • Panels of rods heating water

Bilder und Dateien der Mindmap

• Untitled Artwork (application/pdf)