Carbon cycle & stores Flashcards
What is carbon?
chemically volatile, found in all life forms and sedimentary rocks
What is the carbon cycle?
complex proces carbon goes through as it is transformed from organic carbon (in living organisms) to inorganic and back again
Name the types of carbon
CO2, bio molecules (fats, oils, DNA-produced in living things), hydrocarbons, CH4/methane, CaCO3- calcium carbonate
Primary origins of carbon
stored in mantle when earth formed- escapes at constructive and destructive plate boundaries
remains as CO2 in atmosphere, dissolved in oceans, held as biomass in organisms, bound in rocks
How is carbon measured?
Gtc- gigatonne of CO2
What is a flux?
measurement of the rate of flow of material between stores
What is a carbon sink/store and source?
sink= absorbs more carbon than it releases source= releases more carbon than it stores
What is anthropogenic CO2?
CO2 generated by human activity
Name the 4 main stores
Lithosphere, hydrosphere, biosphere, atmosphere
Where is the lithosphere?
crust and upper mantle
What is the pedosphere?
upper part of lithosphere- layer reacts with atmosphere, hydrosphere and biosphere
How is carbon stored in the lithosphere?
inorganic= fossil fuels, carbon based sedimentary deposits( limestone) organic= litter, organic matter and humic substances found in soil
How is carbon distributed in the lithosphere?
marine sediments and sedimentary rocks- 100 million Gtc
soil organic matter- 1500-1600 Gtc
fossil fuels- 4100 Gtc
Peat- 250Gtc- dead, undecayed organic matter found in boggy areas
Name the 3 hydrosphere stores
Euphotic zone- surface layer- photosynthesis occurs- 900Gtc
Twilight zone- intermediate- deep layer- 37100Gtc
Living organic matter(fish plankton bacteria) 30Gtc
&dissolved organic matter-700Gtc
=37000-40000 Gtc
What happens organisms die?
dead cells, shells, etc. sink into deep water-decay releases co2
some material sinks to bottom- layers of carbon rich sediments- millions of years=rocks(locks carbon)
What is the Biosphere?
total sum of all living matter- oceanic & terrestrial(3170Gtc)
Tropical rainforest=20%, temperate forest=7%, Boreal forest=26%
Main stores of carbon in the terrestrial biosphere?
Living vegetation- 19% carbon in plants- direct in tissues, root system/below ground biomass- russia=25% worlds forest carbon, Amazon basin=20%
Plant litter- 70% leaf tissue in forest, woody litter increases with age
Soil humus- holds more carbon than vegetation- thick brown/black substance that remains after organism has decomposed
Peat- accumulation of partially decayed vegetation or organic matter unique to peatlands (5% of planet cover)
Animals- small role
What do peatlands do?
Saturation obstructs oxygen flow to ground, anaerobic conditions that slow down rates of litter decomposition
Explain the atmospheres carbon significance?
720-800Gtc- co2 higher than it has been for 800000
Small concentration- vital to regulate earths surface temperature as greenhouse gas- industrial co2 increased
What does the Mauna Loa Observatory do?Why?
1958- measures atmospheric carbon
undisturbed air, remote location, minimal human activity
How does the ocean store carbon?
absorbed directly from air, river water discharges carbon in solution
How do plants store carbon?
convert sun’s energy to carbohydrates, store carbon for years, transfer to soil
