Topic 4.3: Carbon cycling Flashcards
Definition of Carbon Cycle
Biogeochemical cycle whereby carbon is exchanged between the different spheres of the Earth
Spheres of the Earth and forms of carbon (4)
a) Hydrosphere (Water) = = HCO3- (aq) / CaCO3 in corals
b) Biosphere (Living things) = Carbohydrates / lipids / proteins
c) Lithosphere (Ground) = Detritus / Fossil fuels
d) Atmosphere (Air) = CO2 / CH4
Diagram of the carbon cycle
a) Sinks
b) Fluxes
Check notes
a) Carbon compounds in fossil fuels
b) Carbon compounds in producers
c) Carbon compounds in dead organic matter
d) Carbon compounds in consumers
e) CO2 in the atmosphere and hydorsphere
CO2 conversions in biosphere
a) Photosynthesis
b) Cell respiration
Autotrophs in CO2 conversion via cell respiration
a) Produce ATP to power metabolic processes
b) CO2 is produced as a byproduct, so it builds up in respiring tissues.
c) Concentration gradient ensures that CO2 can diffuse out.
Organisms in CO2 conversion via photosynthesis
a) Converts CO2 into organic compounds via photosynthesis
b) The CO2 level within an autotorph shoudl lower than the one of the surroundings.
c) This concentration gradient ensures that CO2 can diffuse from the water / air into the autotroph.
CO2 conversions in aquatic environments
a) Dissolution of CO2 in water
b) Calcification and formation of limestone
Dissolution of CO2 in water
a) CO2 dissolves in water to form carbonic acid
b) This increases acidity of water
c) Acidic water can dissolve organism shells and make them more prone to predation
Calcification and formation of limestone
a) Living animals can combine HCO3– with Ca to form CaCO3
b) CaCO3 forms the hardened exoskeleton of coral, as well as the main component of mollusca shells
c) When the organism dies and settles to the sea floor, these components may become fossilized in limestone
CH4 production
a) Organism
b) Condition
a) Bacteria / Methanogenic archaean
b) Anaerobic conditions
Process of CH4 production
a) Bacteria convert organic matter into a mixture of organic acids, alcohol, H2 and CO2
b) Bacteria use the organic acids and alcohol to produce acetate, CO2 and H2
c) CH4 is produced from the by-products of anaerobic digestion
CH4 oxidation
a) Accumulation under the ground
b) Diffusion into the atmosphere
c) CH4 naturally oxidizes to form H2O and CO2
Definition of Peat
Waterlogged soil that contains large amounts of partially decomposed organic matter
Formation of peat (4)
a) Waterlogged regions lack oxygenated air spaces wihtin the soil (Anaerobic condtions)
b) Saprotrophic organisms use anaerobic respiration to produce organic acids, resulting in acidic conditions.
c) These organisms cannot function in acidic / anaerobic conditions, preventing decomposition.
d) Large quantities of partially decomposed organic matter have accumulated and become compressed.
Formation of coal
a) Deposits of peat (from past geological eras) are compressed under sediments (⇑pressure / ⇑heat)
b) This compression of peat removes impurities and produces coal.
