Biogeochemical cycles (yr1) Flashcards
How does deforestation affect the carbon cycle?
Reduces the movement of carbon from the atmosphere to biomass
How does afforestation affect the carbon cycle?
Increases the movement of carbon from atmosphere to biomass
How does marine pollution affect the carbon cycle?
Toxic materials reduce the phytoplankton population which reduces the absorption of CO2.
Some phytoplankton sinks to the floor when dead which increases the amount of Carbon in marine sediments.
Atmospheric carbin would have dissoleved into the sea to maointain equilibrium.
Toxic materials in sea can lead to increased atmospheric levels
How does ploughing affect the carbon cycle?
Increases aeration of soil, so decomposition increases releasing more co2 into the atmosphere
How do anaerobic environments affect the carbon cycle?
Examples - padi fields, landfill sites, anaerobic reservoir sediments, livestock intestines.
They release methane gas that oxidises CO2
(same as methane released during anaerobic respiration and fossil fuel combustion)
How does fossil fuel/wood combustion affect the carbon cycle?
Carbon stored in the biomass is released to atmospheric co2
3 Sustainable management techniques of the carbon cycle?
- Conservation of carbon stores e.g peat bogs
- Alternatives to fossil fuels
- Carbon sequestration
What is carbon capture and storage?
- Carbon is piped underground and stored in structures such as depleted aquifers/oil fields.
- Can also be used to aid oil recovery (secondary recovery)
What is pre-combustion technology in carbon capture and storage?
- Gasification converts fuel like coal to co2 and hydrogen - the co2 can be removed and the hydrogen used as fuel.
- Combustion can be done in pure oxygen so that only water vapour and co2 are produced. (easier to separate)
What is post-combustion technology in carbon capture and storage?
- Carbon can be removed from exhaust gases of fossil fuels combustion through methods such as -
- > dissolving in a solvent
- > high pressure membrane filtration
- > Cryogenic separation (low temp)
Name of bacteria on nitrogen fixing legumes?
Rhizobium
Name of denitrifying bacteria?
Pseudomas
Nitrosomonas bacteria are called?
Nitrites
Nitrobactes bacteria are called?
Nitrates
8 steps of eutrophication?
- Soluble nutrients are dissolved by rainwater and leach into deep soil, unusable for plant roots. Leached nutrients are carried to streams/rivers that may drain into freshwater lakes
- Algal blooms as more amino acids and dna can be synthesised, there is an increase in cell division
- Algae block light - photosynthesising plants under the algae die so less oxygen is produced
- Increase in numbers of decomposers (so more decomp)
- Decomposers break down dead organic matter and use up oxygen in respiration (increased BOD)
- Therefore, less oxygen is available so animals suffocate
- Interspecific competition is reduced
- Anaerobic decomposers thrive and release more nitrates and some toxic chemicals turning the water putrid.
