Biogeochemical Cycles Flashcards
Name the 3 biogeochemical Cycles
- Carbon
- Nitrogen
- Phosphorus
What is a biogeochemical cycle?
The interlinked processes that recycle and reuse a small amount of a resource so that it can be used over long periods of time moving between the bio, atmo, hydro and litho spheres
What are the main reservoirs of the Carbon Cycle? How do they store carbon?
- The atmosphere, stored as Carbon dioxide and monoxide as well as methane
- The hydrosphere as dissolved carbon dioxide
- The biosphere as Carbohydrates, proteins and lipids
- The lithosphere as Carbonaceous rocks such as limestone or fossil fuels like coal
Name and describe the main processes of the Carbon Cycle
- Photosynthesis converts carbon dioxide and water into carbohydrates to be used as energy
- Aerobic Respiration releases carbon dioxide
- Anaerobic Respiration releases methane
- Food webs transfer lipids, carbs and protein between organisms
- Fossilisation produces long-term stores of carbon from incomplete decomposition of organisms or calcium carbonate exoskeletons
- Combustion releases carbon dioxide
How can humans cause changes in photosynthesis (Carbon Cycle)
- Deforestation and Afforestation
- Marine pollution reduces phytoplankton and dead one sink and fossilise
- Climate change kills off photosynthetic organisms like krill
How can humans cause changes in Respiration (Carbon Cycle)
- Dead organic matter in the soil decomposes faster thanks to ploughing
- Rice Padi fields produce methane
- Landfill produces methane
- Livestock produce methane
- Waterlogged field drainage reduces anaerobic environments
What is the main way humans affect the Carbon Cycle
Burning fossil fuels
How can we sustainably manage the Carbon Cycle?
- Conservation of Carbon Sinks like peat bogs and forests
- Alternatives to fossil fuels like solar or wind energy
- Carbon sequestration using mass tree-planting and use of that wood not involving burning
- Carbon Capture and Storage (CCS)
What is CCS? What are the two forms of capture technology?
Carbon Capture and Storage, which involves capturing carbon so it is not released into the atmosphere.
Pre-combustion technologies such as Gasification removes carbon from coal or other fossil fuels before they are burnt.
Post-combustion technologies such as cryogenic separation or high pressure membrane filtration remove it after it is burnt.
What are the main reservoirs of the Nitrogen Cycle? How do they store Nitrogen?
- Atmosphere contains both Nitrogen gas and Oxides of Nitrogen
- Biosphere has living organisms that have nitrogen in DNA and proteins and dead organisms that have proteins and release ammonium as they decompose
- Lithosphere has Ammonium compounds, nitrites and nitrates in the soil
- Hydrosphere has dissolved nitrogen and ammonium
What is ionisation (Nitrogen Cycle)
High energy events like lightning provide energy for nitrogen and oxygen to become oxides of nitrogen
What is Fixation (Nitrogen Cycle)
Some microorganisms can reduce nitrogen to ammonia
What is Nitrification (Nitrogen Cycle)
The oxidisation of ammonium ions into nitrites then to nitrates by nitrifying bacteria
What is Denitrification (Nitrogen Cycle)
The reduction of nitrates into nitrogen and nitrogen oxide gases in anaerobic conditions by denitrifying bacteria
What is Leaching (Nitrogen Cycle)
Highly soluble nitrates being taken from the soil into water, acting as nutrients for plants and algae
What is Ammonification (Nitrogen Cycle)
The amino groups of proteins are released as ammonium ions by decomposers
What is the Haber Process? (Nitrogen Cycle)
An industrial process to produce ammonia from nitrogen a hydrogen using iron catalyst and high temp + pressure for use in fertalisers
What are the impacts of Agriculture on the Nitrogen Cycle
- Nitrate fertilisers increase the problems caused by leaching namely eutrophication
- Field Drainage reduces denitrifying bacteria and increases nitrifying bacteria
- Soil ploughing increases rate of decomposition
- Legumes have nitrogen fixing bacteria in their roots
How does pollution effect the nitrogen cycle?
It increases the oxides of Nitrogen released into the atmosphere
How can we sustainably manage the Nitrogen Cycle?
- Controlling combustion to reduce NOx release and unable to do that, using catalytic convertors and urea sprays to prevent them entering the atmosphere
- Replacing manufactured fertilisers with organic ones like manure
- Responsible management of agriculture by planting legumes, using crop rotation, avoiding fertilisers during rain and use of low-tillage techniques
What are the main processes of the Phosphorus Cycle?
- Absorption by roots, most use a symbiotic relationship with fungi to improve the efficiency
- Decomposition releases phosphates from proteins that are often made soluble and dissolved by plants
- Sedimentation traps phosphorus in organic matter but can decay over time and be released into the water
- Continental drift and mountain building are mostly responsible for major movements
How can humans impact the Phosphorus Cycle?
- Mining phosphate rocks to create ammonium phosphate
- Accumulations of Bird shit can contain phosphate
- Fertilisers mobilise phosphate
How can we sustainably manage the Phosphorus Cycle?
- Biological waste can be used as fertiliser
- Crop breeding programs to increase phosphorus uptake efficiency
