4.3 carbon cycling Flashcards
what do autotrophs do?
they make their own energy.
they convert CO2 from the atmosphere into carbohydrates (glucose) and other carbon compounds during photosynthesis.
inorganic carbon is turned into organic carbon thus it reduces the atmospheres CO2 concentration.
carbon dioxide in water enviroments.
CO2 is soluble in water.
either stay as gas CO2 or combines with water to make carbonic acid H2CO3
carbonic acid in water.
it can disassociate, forming hydrogen ions (H+) and hydrogen carbonate. the H+reduces the pH of the water and makes it acidic
what is the diffusion of CO2 in autotrophs?
the CO2 is used up by the plant to reduces the concentration of CO2 in the plant and makes a gradient.
Bc there’s more CO2 in the air than the plant, CO2 diffuses into the plant through stomatal pores on the underside of leaves (land) or whole leaf and stem (aquatic)
CO2 in cell reproduction.
CO2 is a waste product from aerobic and anaerobic cell respiration. the CO2 made, diffuses out of cells into atmosphere or water.
glucose + oxygen = CO2
what is methane?
methane (CH4) is naturally made in an anaerobic respiration by methanogenic bacteria as a waste product.
what is methanogenesis?
3 groups of prokaryotes in the process:
- bacteria convert organic matter into organic acids, alcohol, CO2 and H
- bateria convert organic acids and alcohol into ethanoic acid, CO2 and H
- methanogenic archaeans convert CO2, H and acetate into methane by:
CO2 + 4H2 –> CH4 +2H2 O
CH3 COOH –> CH4 + CO2
what is methanogenesis in anaerobic environments?
Archaeans
- mud along shores and beds of lakes
- wetlands where soil is waterlogged
- guts of termites, cattle or sheep
- landfill sites where organic matter has been buried.
methane produced from archaeans goes into atmosphere or accumulates in ground as fuel.
how is methane oxidised?
remains in atmosphere for 12 years.
oxidised into water and CO2 in stratosphere by monoatomic oxygen and highly reactive hydroxyl radicals.
how is peat formed?
when soil becomes water-logged it creates an anaerobic environment and saprotrophs can’t fully decompose organic matter.
causes acidic conditions and organic matter builds up and compresses forming brown acidic material - peat
how is coal formed?
it is formed when deposits of peat are berried under other sediments then compressed and heated.
how are oil and gas formed?
- they are formed in mud at the bottom of seabeds and lakes where incomplete decomposition occurs by anaerobic conditions.
- mud and sediments are deposited and the organic matter is compressed and heated.
- chemical changes happen and make complex mixtures of liquid carbon compounds and gases.
- the mixtures are crude oil and natural gas
what is combustion?
when organic matter or biomass is heated to ignition and O is available then it will set alight in a combustion reaction.
products are CO2 and H2O
fossilised organic matter are burnt as fuels.
how is limestone formed?
some animals like molluscs and hard corals have hard parts made of calcium carbonate, when dead the soft part decomposes.
in acidic conditions, the hard part dissolves but in neutral or alkaline conditions the hard part deposits in seabed and forms limestone.
what is the photosynthesis flux?
120 gigatonnes per year-1
what is the cell respiration flux?
119.6 gigatonnes per year -1
what is the combustion of fossil fuels flux?
6.4 gigatonnes per year-1
where is carbon dioxide and methane measured?
Mauna Loa observatory in Hawaii, bc its at the equator and close to sun.
