3.1.1.3- carbon cycle Flashcards
stores of carbon (what spheres have largest- smallest)
(in order of decreasing magnitude)
(%= % of total carbon in each store)
LITHOSPHERE- 99.983%
HYDROSPHERE- 0.0076%
PEDOSPHERE- 0.0031%
CRYOSPHERE- 0.0018%
ATMOSPHERE- 0.0015%
BIOPSHERE- 0.0012%
what can every carbon store be?
carbon source-release more carbon than absorbs
or
carbon sink- absorbs more carbon than releases
lithosphere what’s carbon stored in + for how long?
- sedimentary rocks e.g. limestone (calcium carbonate), hydrocarbons (fossil fuels), marine sediments (shells + skeletons)
- long-term storage (240-300mill years)
hydrosphere what’s carbon stored in + for how long?
- 90%= oceanic carbon dissolved as bicarbonate, carbonate ions dissolved + dissolved as CO2
- storage= dynamic –> surface= 25 years, deep= 1250 years
pedosphere what’s carbon stored in + for how long?
- soil stores, 300bn tonnes of carbon as organic matter, soil organisms + remains of dead plants + animals
- peat soils hold highest amount of carbon
- storage= days to 1000 years
cryosphere what’s carbon stored in + for how long?
- permafrost (frozen ground) of tundra + artic regions contains plant material
- storage= 1000s of years, ice cores=millions of years
atmosphere what’s carbon stored in + for how long?
- carbon forms= CO2, methane (CH4)
- storage= 6 years
biosphere what’s carbon stored in + for how long?
- forms of carbon= living plants + animals
- storage= 18 years
is the carbon cycle an open or closed system?
closed
abiotic vs biotic components
abiotic components= move carbon slower through cycle
biotic= move carbon through cycle quickly
transfers of carbon?
photosynthesis
respiration
decomposition
combustion
weathering
sequestration
burial + compaction
photosynthesis
- living organisms convert CO2 from atmosphere + water from soil into oxygen + glucose using light energy
( removes CO2 from atmosphere) e.g. phytoplankton
respiration
converts glucose into energy + returns CO2 to atmosphere
decomposition
- when living organisms die they’re broken down by decomposers (bacteria, fungi) which respire= returns co2 to atmosphere + carbons from dead organisms body return to atmosphere as CO2. other carbons= returned to soil
- decomposition= temp dependent, warmer= faster + more activity water regulates decomposition rate + release of carbon. Heavily water logged areas e.g. peats= slow rate of decomposition
combustion
- e.g. burning fossil fuels, wildfires, tectonic activity etc
- releases CO2 to atmosphere after being stored in rocks for thousands/millions of years
weathering
- chemical weathering= carbonation
–> CO2 in atmosphere combines with water vapour= produces weak acid called carbonic acid= makes precip acidic= calcium carbonate in rocks reacts with acidic water + forms calcium bicarbonate which is soluble + removed in solution by percolating water via rivers, oceans etc + eventually back to atmosphere
sequestration
natural sequestration= carbon removed from atmosphere + stored in liquid/solid form
carbon capture + storage= term to describe process of capturing co2 from industrial sources e.g. power stations –> then it’s transported to long-term storage location
burial + compaction
- oceans absorb carbon from atmosphere which goes into shells + skeletons of marine creatures as CACO3
–> when they die it sinks + overtime becomes compact to create sedimentary rocks e.g. limestone
–> heat + pressure= carbon from organic matter is converted to hydrocarbons
carbon transfer at local/plant scale
e.g. tree
- carbon store –> takes carbon from atmosphere (photosynthesis)
- fallen leave= carbon transferred to soil
- soil + leaf litter= stores of carbon
- carbon lost from soil due to soil respiration, tree respiration= carbon returns to atmosphere or decomposition of organic matter or combustion from wild fires
transfer of carbon at a continental scale
- involves all fast + slow carbon cycles
- rate of transfers varies due to changing conditions on planet
- human activity has influences
carbon transferred at SERE scale
- e.g. lithosere (example of terrestrial carbon cycle)
- ‘sere’= stage in the succession of vegetation in an ecosystem
- lithosere= vegetation succession that occurs on bare rock
- hydrosere= occurs in freshwater
- halosere= occurs in salt-rich conditions
- psammosere= occurs in sandy areas
- when environmental equilibrium is reached= further successions stop + final stage of sere is reached
–> this is usually in response to climate so is called ‘climatic climax’ - climax vegetation for lithosere in UK= deciduous wood
- normally involves complex stores + transfers
