Carbon cycle EQ1 Flashcards
When was gasses added to the atmosphere and how
Precambrian geological period, volcanic activity added carbon dioxide (CO,), water (H,0) and sulphur dioxide (SO,) to the atmosphere
Explain how oxygen was added to the atmosphere and when
cyanobacteria started photosynthesising 3 billion years ago
Whats the result of primitive bacteria photosynthesizing
allowed more complex organisms to develop about 2 billion years ago
How does CO2 enter the oceans
By dissolving
When has the carbon balance been altered and how
1800 by human activities such as deforestation and the burning of fossil fuels
What are carbon stores
Sources (adding carbon to the atmosphere) and sinks
What is carbon fluxes?
Movement of carbon from one store to another
Give examples of carbon stores
Atmosphere
Hydrosphere
Lithosphere
Biosphere
What are the major fluxes
between the oceans and the atmosphere
between the land and atmosphere
largest carbon store is?
geological
How much carbon is in the lithosphere?
over 100 million Pg of carbon
Where is most lithos carbon concentrated
Sedimentary rocks
Describe the formation of Sedimentary rocks
Sediment is deposited
Further layers are deposited and sediment undergoes diagenesis
compressed and chemical reactions cement particles together
lithification happens
What are the characteristics of limestone?
Composed of calcium carbonate
80% of lithospheric carbon is found in limestones
How can Geological carbon can also be released into the atmosphere?
Chemical weathering through carbonic acid
Outgassing
Explain chemical weathering of rocks by carbonic acid
carbon dioxide in the atmosphere reacts with moisture to form weak carbonic acid
reacts with some of the surface minerals and slowly dissolves them
Decomposition of rock minerals
What is diagenesis?
physical and chemical changes that occur during the conversion of sediment to sedimentary rock
Explain outgassing
pockets of carbon dioxide exist in the Earth’s crust
Volcanic eruptions and earthquakes can release these gas pockets
Outgassing is the release of gas, previously dissolved, trapped, frozen or absorbed in some material
Where does outgassing usually occur?
along mid-ocean ridges, subduction zones and at magma hotspots.
How much carbon sinks into deeper waters in the biological pump?
30%
Explain how sedimentary rocks are formed from phytoplankton?
Photosynthesis –> accumilates –> cemented
Explain the biological pump
These move carbon dioxide from the ocean surface to marine plants called phytoplankton through photosynthesis
converts carbon dioxide into food for zooplantic (microscopic animals) and their predators.
Most of the carbon dioxide taken up by phytoplankton is recycled near the surface. About 30% sinks into deaper waters before being converted back into carbon dioxide by marine bacteria.
Explain the physical pump
These move carbon compounds to different parts of the ocean in downwelling and upwelling currents
Downwelling currents bring dissolved carbon dioxide down to the deep ocean.
Eventually, these deep ocean currents, part of the thermohaline. circulation, return to the surface by upwelling.
The cold deep ocean water warms as it rises towards the ocean surface and some of the dissolved carbon dioxide is released back into the atmosphere.
Explain the carbonate pump.
These form sediments from dead organisms that fall to the ocean floor, especially the hard outer shells and skeletons of fish, crustaceans and corals, all rich in calcium carbonate.
What is the thermohaline circulation?
The thermohaline circulation is the global system of surface and deep ocean currents driven by temperature and salinity differences between different parts of the ocean
What are examples of terrestrial sequestering?
Plants photosynthesizing –> enters the food chains/nutrient cycles
Animals consuming plant matter –> fats and protiens –> respiration
Waste from animals eaten by micro organisms
When plants and animals die, carbon is released into the soil
How much of the human body is carbon in weight?
18%
How do Carbon fluxes vary?
Diurnally
Seasonally
What does the amount of carbon stored in the soil depend on? (List)
Climate
Vegetation cover
Soil type
Land use
Explain how carbon fluxes diurnally?
during the day, fluxes are positive - from the atmosphere into the ecosystem. The reverse applies at night when respiration occurs but not photosynthesis.
Explain how carbon fluxes seasonally?
during winter, carbon dioxide concentrations increase because of the low levels of plant growth. However, as soon as spring arrives and plants grow, these concentrations begin to decrease until the onset of autumn.
What is carbon synthesised into in plants and animals?
Simple sugars
Fats, proteins, nucliec acids
How does soil type the amount of carbon stored in the soil?
clay protects carbon from decomposition
How does vegetation cover affect the amount of carbon stored in the soil?
Affects the supply of dead organic matter
What is the largest carbon store on land and how is it released
Soils - dead organic matter
Biological decomposition
How does climate affect the amount of carbon stored in the soil?
dictates the rates of plant growth and decomposition
whats the carbon cycle
the cycle by which carbon moves from one earth sphere to another. its a closed system made up of interlinked subsystems which are open and have inputs and outputs
what are the 3 places where carbon is stored
terrestrial
atmospheric
oceanic
atmosphere and how carbon is found
co2 and carbon compound such as methane (CH4)
How does land use affect the amount of carbon in soil?
cultivation and other forms of soil disturbance increase the rate of carbon loss
liposphere and how carbon is found
as carbonates in limestone, chalk and fossil fuels, as pure carbon and diamonds.
lisosphere=rock that covers our planet
hydrosphere and how carbon is found
as dissolved CO2
hydrosphere= water on our planet
rate of flux and explanation photosynthesis and respiration in plants
the quickest cycle
-plants take carbon from the atmosphere through photosynthesis, they then release it by respiration, temp and moisture control the rate.
what are 3 organic carbon fluxes (terrestrial)
photosynthesis and respiration in plants
decomposition
transformation into sedimentary rock
rate of flux and explanation decomposition
depends on climate
-warmer= faster rate, some organic material may be buried so deeply that they don’t decay at all and turn into hydrocarbons- they then release co2 when burnt
rate of flux and explanation transformation into sedimentary rock
a long period of time
due to decomposition
what’s carbon sequestration
the process by which co2 is removed from the atmosphere and held in solid or liquid form, its the process which facilitates the capture and storage of carbon
whats the impact of volcanic eruptions?
to send extra co2 into the atmosphere, which leads to rising temps, increased evaporation and higher levels of atmospheric moisture, this increases acid rain and thus chemical weathering which slowly rebalances the cycle
lay out the 1st mechanism of the geological carbon cycle
-Rivers transport weathered carbon and Ca sediments to the oceans where they ae deposited.
lay out the 2nd mechanism of the geological carbon cycle
-carbon in organic matter from plants, animal shells ad skeletons sink to the ocean bed when they die, building up a strata of coal, chalk and limestone.
lay out the 4th mechanism of the geological carbon cycle
-the presence of intense heating long subduction plate boundaries changes sedimentary rock into metamorphic rock. CO2 is released by the metamorphism of rocks rich in carbonates during this process
lay out the 3rd mechanism of the geological carbon cycle
-carbon rich rocks are sub ducted along plate boundaries and eventually emerge again when volcanoes erupt.
lay out the 6th mechanism of the geological carbon cycle
-CO2 within the atmosphere combines with rainfall to produce a weak acid ( carbonic acid or acid rain) that dissolves carbon rich rocks, releasing bicarbonates. This is chemical weathering
whats decomposition
breaking down organic matter and releasing co2 into soils
lay out the 5th mechanism of the geological carbon cycle
- terrestrial carbon held within the mantle is released into the atmosphere as co2 when volcanoes erupt, this is outgassing
whast combustion
biomass and fossil fuels- releasing co2 into the atmosphere
what is the bio-geochemical carbon cycle made up of and what is it?
is where co2 is exchanged between the atmosphere and the ocean, it consists of…
-photosynthesis
-respiration
-decomposition
-combustion
what’s the second largest carbon store
ocean
what are the two carbonate pumps in the ocean
biological pump
physical pump
what are the 4 types of biological- terrestrial ( land based) sequestering?
Trees
mangroves ( a vital store of carbon)
tundra/permafrost
rainforests
biological- terrestrial ( land based) sequestering- trees- link to carbon cycle and prediction for the future
95% of a trees biomass is leaves, branches trunk and root which is made up from co2 that sequesters and converts into cellulose. the amount of carbon stored depends on the balance between photosynthesis and respiration
- due to deforestation, carbon absorption will be decreased and carbon stored will be released.
biological- terrestrial ( land based) sequestering- mangroves link to carbon cycle and prediction for the future
sequesters almost 1.5 metric tones of carbon per hectare every year. mangrove soil consists of high amounts of humus and peat which contains high amounts of carbon- the soils are anaerobic so decomposition is slow so little carbon is respired back to the atmosphere and the stores remain intact. any plant matter trapped by tree rocks tends to stay as it decomposes slowly
-if mangroves were cleared, carbon would be released- mangroves are currently being cleared for tourism …
biological- terrestrial ( land based) sequestering- tundra/permafrost- link to carbon cycle and prediction for the future
much of the soil in the tundra region is frozen containing stores of ancient c. c is locked in an icy carbon store. and has been trapped there for many years.
-if permafrost melts stored c will release co2 and methane causing global warming
biological- terrestrial ( land based) sequestering- rainforests- link to carbon cycle and prediction for the future
-rainforests= huge c sinks. c is stored in trees, plant litter and dead wood. soils= thin and lack nutrients due to litter layers that cover them. as the litter and dead wood decay, they are recycled so quickly that a soil store does not develop- the nutrients released are rapidly consumed by vegetation due to decomposition. rainforests absorb more co2 than any other terrestrial biome
-if rainforests all died off, a massive carbon sink would be lost. co2 lost= greenhouse effect=temps rise
fewer rainforests= less water pumped into atmosphere=temps rise= forest fires (positive feedback loop)
what can biological carbon be stored as and how is it returned to the atmosphere
stored as dead organic matter in soils or returned to the atmosphere via biological decomposition over several years
what are primary producers
Producers that use solar energy to produce biomass
sequestcarbon
whats the greenhouse effect
the warming of the atmosphere as gasses such as CO2 CH4 and water vapour absorb heat energy from the earth
whats the enhanced greenhouse effect
the increase in the natural greenhouse effect said to be caused by human activities that increase the quantity of GHG’s in the atmosphere, these gasses are coming from- cattle, rice paddy fields, domestic heating, factories, vehicle engines an air travel
describe albedo (local)
white coloured surface= high albedo ( greater reflection)
dark coloured surface=low albedo (lots of absorption)
describe ocean currents (global)
ocean currents distribute water from warm areas to cold areas. warm water from the equator is re-distributed- keeps many places warmer than they would be
what are the 3 global controls of climate
latitude
atmospheric circulation cells
ocean currents
what are the 2 local controls of climate
albedo
altitude
whats a fossil fuel
a natural fuel such as coal or gas, formed in the geological past from the remains of living organisms.
they are extremely important long term carbon stores
what are the 4 impacts of fossil fuel consumption
CLIMATE- global temps increase due to increased CO2 in atmosphere, extreme weather events become more frequent
BALANCE-if sources and sinks are equal, the carbon cycle is said to be in equilibrium, fossil fuel consumption alters this balance
ARTIC AMPLIFICATION - the artic region is warming twice as fast as the global average which is ARTIC AMPLIFICATION. melting permafrost releases CH4 and CO2 leading to increased global temps and further melting (positive feedback loop)
HYDROLOGICAL CYCLE- changes to temperature will lead to change in precipitation patterns, snowfall is likely to reduce
what are the possible implications on a 2 degree temperature increase
implications on climate, ecosystems and hydrological cycle.
ECOSYSTEMS- habitat changes will mean 10% of land species with limited adaptability will die of extinction.
- by 2080, shifting temps may reduce bird habitats
HYDROLOGICAL CYCLE- rivers will dry up in regions where precipitation is reduced.
- decrease in water availability
CLIMATE
-temperate and tropical zones may experience stronger storm activity due to more heat energy in the atmosphere
