Biogeochemical cycles Flashcards
Carbon reservoir: atmosphere
CO2, CH4, CO
smallest store
Carbon reservoir: hydrosphere
CO2 dissolves in water
Carbon reservoir: lithosphere
carbonate rocks
hydrocarbons
largest store
Carbon reservoir: biosphere
DOM
carbohydrates
proteins
lipids
How carbon moves from one reservoir to another and in what form: photosynthesis
atmosphere to biosphere
CO2 to glucose
How carbon moves from one reservoir to another and in what form: respiration
biosphere to atmosphere
glucose to CO2
produces energy from glucose by producing ATP
How carbon moves from one reservoir to another and in what form: food chain transfer
biological molecules are transferred from one organism to another
energy decreases up each trophic level
How carbon moves from one reservoir to another and in what form: fossilisation
biosphere to lithosphere
carbohydrates to hydrocarbons
layers of sediment build up around the DOM, it begins to compact and form rocks
How carbon moves from one reservoir to another and in what form: combustion
biosphere/lithosphere to atmosphere
carbohydrates to CO2 and CO
fossil fuels are burned to release CO2 and CO
How carbon moves from one reservoir to another and in what form: decomposition
biosphere to lithosphere/atmosphere
carbohydrates to hydrocarbons/CH4
How carbon moves from one reservoir to another and in what form: volcanic activity
lithosphere to atmosphere
hydrocarbon to CO2
carbonated rocks are melted to magma, when magma reaches the surface CO2 is released
How human activities impact the carbon cycle: deforestation
decreases photosynthesis, decomposition and food chain transfer
reduced amount of CO2 absorbed from atmosphere
land is used for agriculture and cattle ranching
How human activities impact the carbon cycle: combustion of fossil fuels
increases CO2 in atmosphere
contributes to greenhouse effect
global temperature rise
anthropogenic climate change
How human activities impact the carbon cycle: afforestation
increases photosynthesis, decomposition and food chain transfer
CO2 is absorbed from atmosphere
How human activities impact the carbon cycle: intensive farming
increases CO2 in atmosphere and biosphere and combustion
contributes to greenhouse effect
increased combustion for machinery
ploughing of soil releases CO2
How human activities impact the carbon cycle: cattle farming
increases CH4 in atmosphere and CO2 in biosphere
decreases photosynthesis
contributes to greenhouse effect
anaerobic conditions release CH4
How human activities impact the carbon cycle: ocean pollution
increased CO2 in atmosphere and hydrosphere
decreased photosynthesis
reduces number of phytoplankton and algae
ocean acidification
less CO2 removed from atmosphere and oceans
Nitrogen reservoir: atmosphere
N2 = 78%
NOXs
Nitrogen reservoir: biosphere
DNA, proteins, amino acids, RNA
Nitrogen reservoir: lithosphere
soil = ammonia, nitrates, nitrites
Nitrogen reservoir: hydrosphere
dissolved nitrates
dissolved ammonia
How nitrogen moves from one reservoir to another and in what form: ionisation
lightning provides energy for atmospheric nitrogen and oxygen to react
produces oxides of nitrogen
How nitrogen moves from one reservoir to another and in what form: fixation
micro-organisms chemically reduce N2 to NH3
How nitrogen moves from one reservoir to another and in what form: food chain transfer
nitrogen passes between organisms as amino acids and proteins in food
How nitrogen moves from one reservoir to another and in what form: nitrification
involves oxidation of ammonium ions to nitrites then nitrates using nitrifying bacteria
How nitrogen moves from one reservoir to another and in what form: denitrification
chemical reduction of nitrates in soil to nitrogen and nitrogen oxides
requires anaerobic conditions
How nitrogen moves from one reservoir to another and in what form: leaching
nitrates = highly soluble
easily leached out of soil
act as nutrients for aquatic plants and algae
How nitrogen moves from one reservoir to another and in what form: absorption by roots
absorb nitrogen as soluble ions (ammonium and nitrates)
How nitrogen moves from one reservoir to another and in what form: ammonification
amino groups in proteins released as ammonium ions when DOM decomposes
How human activities impact the nitrogen cycle: haber process
iron catalyst, high temp and pressure
uses lots of energy
N2 + 3H2 —> 2NH3
NH3 —> NO3-
How human activities impact the nitrogen cycle: agricultural activities - use of fertilisers
eutrophication
How human activities impact the nitrogen cycle: agricultural activities - drainage systems
makes soil more aerobic
increases nitrifying bacteria and decreases denitrifying bacteria
How human activities impact the nitrogen cycle: agricultural activities - soil disturbance
ploughing releases NOXs into atmosphere
increases rate of decomposition
How human activities impact the nitrogen cycle: agricultural activities - choice of crop
legumes increase levels of nitrites and nitrates in the soil
How human activities impact the nitrogen cycle: pollution
NOXs released into atmosphere by combustion
increases quantity of nitrates added to the soil by rain
Explain the process of eutrophication
farmers add fertiliser to soil
excess nutrients runoff from field to water
causes algal bloom
algae blocks sunlight and uses up O2
algae dies and is decomposed by bacteria
decomposition of algae = increased biological demand for O2
water becomes anoxic
fish and other aquatic life dies
Phosphorus reservoir: plants and animals
proteins, DNA, RNA, phospholipid, ATP
Phosphorus reservoir: sediments and rocks
present in phosphate rocks
Phosphorus reservoir: water
phosphate ions go into solution
Why is phosphorus often a limiting factor in plant growth?
no gaseous reservoir so slower to cycle
phosphate ions are less soluble than nitrate ions (low solubility)
How phosphorus moves from reservoir to another and in what form: absorption by roots
phosphate ions in solution
solution taken up by plant roots
used in synthesis or organic molecules
How phosphorus moves from reservoir to another and in what form: food chain transfer
moves through trophic levels when one organism eats another
How phosphorus moves from reservoir to another and in what form: decomposition
microbes break down DOM
phosphates returned to soil
How phosphorus moves from reservoir to another and in what form: sedimentation
phosphates in sediments end up in rocks
phosphate originates from DOM
How phosphorus moves from reservoir to another and in what form: mountain building - uplift
plate tectonics move rocks from deep to surface
How phosphorus moves from reservoir to another and in what form: weathering/erosion
rocks at surface are weathered and then eroded
What human activity causes the most impact on the movement and storage of phosphorus? What problems can this cause?
production of fertiliser - eutrophication
mining for phosphorus - pollution
Sustainable management of the carbon cycle
reduce combustion of fossil fuels
increase use of renewables
afforestation
carbon capture and storage
protect existing carbon stores
Sustainable management of the nitrogen cycle
reduce reliance on artificial fertiliser
use fertiliser during dry spells
educate farmers around eutrophication
collect runoff and return to farmland
reduce use of combustion engines
catalytic convertors
Sustainable management of the phosphorus cycle
use of natural fertilisers
leave DOM to decay on soil
breed crops to increase efficiency of phosphorus uptake
