Carbon - EQ1 - Flashcards
What is carbon
- a common element on earth
- it exists in gas, liquid & solid forms
- in both biotics & abiotic forms
Where can carbon be found
- living material
- rocks & sediments
- oceans & rivers
- atmosphere
In the carbon cycle, the exchange of carbon is between _ main stores
4
What are the 4 main stores in the carbon cycle
- biosphere - plants & animals
- lithosphere - rocks & sediments
- hydrosphere - oceans
- atmosphere - the air
Like in the (1), there is (2) amount of carbon on earth
- hydrological cycle
- only a certain
What are the 3 forms of carbon
- inorganic (found in rock)
- organic (found in plant material)
- gaseous (CO2, CH4)
Carbon cycle - Fluxes
stores ____ in size
vary
What is a carbon flux
- the process of transferring the carbon between these reservoirs
What do fluxes usually involve
- a biogeochemical reaction (photosynthesis, respiration, decomposition & combustion)
What can fluxes be measured in
Pg - Petagrams
GT - Gigatons
(both equal 1 billion tonnes)
What are the different timescales of carbon fluxes
- seconds to minutes
- annual
- 10-500 years
- millions of years
Give an example of a carbon flux on a time scale of seconds to minutes
- plants absorb carbon through photosynthesis then transpire this back into the atmosphere
Give an example of a carbon flux on a time scale of annual
- seasonal variations in the biosphere (e.g autumn leaves)
Give an example of a carbon flux on a time scale of 10-500 years
- carbon from dead plant material can be incorporated into soils,
- where it may stay for years, decades or centuries,
- before being broken down by soil microbes, & released back into the atmosphere
Give an example of a carbon flux on a time scale of millions of years
- organic matter that becomes buried in deep sediments & protected from decay
- was slowly transformed into deposits of coal, oil & natural gas, the fossil fuels we use today
- when we burn these substances once again to the atmosphere in the form of CO2
What is the scientific view of how old the earth is
4.6 billion years old
When did dinosaurs exist
- The Mesozoic period,
- in the Triassic & Jurassic eras
When did humans first evolve
- 300,000 to 400,000 years ago
What are Cyanobacteria & Stromatolites
- Primitive bacteria, which started photosynthesising, adding oxygen to the atmosphere & absorbing CO2
- This happened un the Cambrian era & this evolutionary step enabled life as we know it to evolve
Why is the carboniferous period so significant
- From 360 mya to about 300 mya, in the middle of this period, the carboniferous rainforest collapsed, resulting in the depostion of many coal beds
Where does the word ‘Carboniferous’ come from
- The latin word, ‘carbo’, meaning coal
- Carboniferous means coal-bearing
The global carbon cycle, one of the major…………. cycles, can be divided into….
- biogeochemical
- geological & biological compounds
Describe the ‘Geological carbon cycle’
- Slowest reservoir turnover rate - at least 100,000 years
- The rate carbon enters & leaves is very slow
- Carbon is stored in rocks/sediment & only leaves through volcanic emissions or through chemical weathering of rocks
Describe the ‘Biological carbon cycle’
- Faster reservoir turnover rate
- Carbon is not sequestered for long & flows between oceans, atmosphere & vegetation
Define sequestering
- the natural storage of carbon by physical or biological processes, such as photosynthesis
Explain the ‘Geological Carbon Cycle’
1. Volcano
- Terrestrial carbon, held within the mantle, is released into the atmosphere as carbon dioxide when volcanoes erupt
- This is known as ‘outgassing’
Explain the ‘Geological Carbon Cycle’
2. rainfall
- CO2 within the atmosphere combines with rainfall
- to produce a weak acid (carbonic acid aka acid rain)
- that dissolves carbon-rich rocks, releasing bicarbonates
Explain the ‘Geological Carbon Cycle’
3. Rivers
- Rivers transport weathered carbon & calcium sediments to the ocean, where they are deposited
Explain the ‘Geological Carbon Cycle’
4. organisms
- Carbon in organic matter from plants & from animal shells & skeletons,
- sinks to the ocean bed when they die,
- building up strata of coal, chalk & limestone
Explain the ‘Geological Carbon Cycle’
5. tectonics
- Carbon-rich rocks are subducted along plate boundaries & eventually emerge again when volcanoes erupt
Explain the ‘Geological Carbon Cycle’
6. metamorphism
- The presence of intense heating along subduction plate boundaries, metamorphose (or alters) sedimentary rocks by baking, creating metamorphic rocks
- CO2 is released by the metamorphism of rocks rich in carbonates during this process
In the carbo cycle there is a natural…
balance between carbon production & absorption within the cycle
In the carbo cycle there can be occassional ……….. e.g…
- disruptions
- major volcanic eruptions emit large quantities of carbon into the atmosphere
What is the impact of volacnic eruptions in the atmosphere
- extra CO2 sent into the atmosphere
- which leads to rising temperatures, increased evaporation & higher levels of atmospheric moisture
- this increases aci rain & therefore chemical weathering which slowly rebalances the cycle
Most of the earth’s carbon is ………….
geological
Most of the earth’s carbon is geological, & results from:
- the formation of sedimentary carbonate rocks in the ocean
- carbon derived from plants & animlas in shale, coal & other rocks
In the oceans today, ….% of carbon-containing rock is from….
- 80%
- shell-building (calcifying) organisims e.g corals & plankton
How does the fromation of sedimentary rock form th earth’s carbon
-limestone
- After organisms die, they sink to the sea floor
- Overtime layers of shells sediment are cemented together & lithified (turned to rock), storing the carbon in stone - limestone & its derivatives
Define calcifying
- to make someting hard, especially by the addition of substances containing calcium
How is shale a geological store of carbon
- The remaining 20% of rocks contain organic carbon from organisms that have been embedded into layers of mud
- Over millenia, heat & pressure compresses the mud & carbon, forming sedimentary rock like shale
How is coal a geological store of carbon
- fossil fuels were made up to 300 million years ago from the remains of organic material
- organisms once dead, sank to the bottom of rivers & seas, & were covered in silt & sand & then started to decay anaerobically
How is coal a geological store of carbon
-Anaerobic decay operates over ……..
- millenia
How is coal a geological store of carbon
-what are the products of anaerobic decay
methane and carbon dioxide
How is coal a geological store of carbon
-the deeper the deposit, the more…
heat & pressure is exterted on the deposits
Define soil respiration
- a measure of carbon dioxide (CO2) released from the soil from decomposition of soil organic matter (SOM) by soil microbes
Define respiration
- a process in living organisms involving the production of energy, typically with the intake of oxygen & release of CO2
Define photosynthesis
- the process by which green plants & some other organisms use sunlight to synthesize nutrients from carbon dioxide & water
Define diffusion
- the process by which CO2 interacts with the ocean, either being released or absorbed
Define sinking
- descend from a higher to a lower position; drop downwards
Define decomposition
- process by which dead organic susbtances are broken down into simpler organic or inorganic matter such as carbon dioxide
Define rock cycle
- the basic concept in geology that describes transitions through geological time among the three main rock type: sedimentary, igneous & metamorphic
Molecules of CO2 enter the ocean by…
- dissolving into the ssea surface waters via diffusion
The amount of CO2 that diffuses & dissolves in the sea surface water depends on…
variables such as wind, sea surface mixing, concentration of CO2 & the temperature of the water
Once dissolved in surface seawate, how can CO2 enter into the ocean carbon cycle
- Through 3 different mechanisms:
- the physical carbon pump
- the biological carbon pump
- the carbonate pump
Thermohaline Circulation
What is a conveyor
- warm currents tends to be at the surface & cold currents tend to be deep in ocean currents travelling back along the bottom of the ocean
Thermohaline Circulation
Why is an oceanic converyor important
- it balances the climate, responsible for moving carbon & also heat
Themohaline circulation only happens because of…
- brine rejection –> if we turn this off, all ocean currents will cease to exist
What is brine
- really salty water
Where does brine rejection take place
- really cold parts of the world, around Greenalnd, near the Artic Ocean
Summarise what takes place in brine rejection
- It is the process that occurs when salty water freezes,
- the salts do not fit in the crystal structure of water ice,
- so the salt stays in the water beneath the ice
The Physical Carbon Pump Process
- Where does Brine Rejection occur
- It occurs when warm water in oceanic surface currents are carried from the equator to the poles (high latitudes) where it cools
The Physical Carbon Pump Process
- Explain the process of brine rejection
- Brine rejection makes the water vert salty,
- the salt makes the water dense enough to sink in some places all the way to the deep ocean floor,
- where it can remain for hundreds of years
The Physical Carbon Pump Process
- What happens once the seawater is cool
- When seawater is cool it takes up more CO2,
- so when cold water upwells to the surface & warms up again,
- it loses CO2 to the atmosphere (carbon flux)
The Physical Carbon Pump Process
- Thermohaline circulation
- the thermohaline circulation ensures CO2 is constantly ebing exchanged betwee the ocean & the atmosphere, acting as an enornmous carbon pump
Explain the issues of the Physical Carbon Pump
Coral bleeching
- especially along the equator, more carbon in the atmosphere, which goes into the coral, & too much bleaches it
Explain the issues of the Physical Carbon Pump
ice sheets
- ice sheets melting
- brings more freshwater into the ocean
- so thsi freshwater dilutes the salty water
Explain the issues of the Physical Carbon Pump
Gulf Stream affected
- During 2004, the North Easterly Atlantic current, the Gulf Stream, appeared to stall for 10 days,
- evidence shows that the speed of oceanic circulation between the Gulf of Mexico & Europe had slowed by 30% since 2000
What drives the Biological carbon pump
organisms, in particular, phytoplankton
The biological carbon pump involves….
- marine organisms, photosynthesising, respiring, consuming, producing waste, dying & decomposing
What are phytoplankton
- microscopic, single-celled organisms that drift in the sun-lit surfaces of the world’s oceans
What is generated through photsynthesis by phytoplankton
Phytoplankton, use sunlight to turn carbon into organic matter
The carbon generated by phtoplankton in photosynthesis then enters…
the marine food web
Living organisms move carbon from the atmosphere to…
the shallower ocean, then the deep ocean when they die & sink down as marine snow
Define marine snow
a shower of organic material falling from the upper waters, to the deep ocean (twilight zone)
The biological pump doesn’t move as much carbon as its very….
seasonal
In certain areas of the palnet, you aren’t going to get much……..occurring in these areas, where its really…
- photosynthesis
- dark, in the cold ocean
In winter months, more carbon being….
absorbed & more death occurring
The carbonate pump
What can be found in the ocean which is important to the ocean carbon cycle
- the ocean naturally contains many dissolved chemicals which are especially important to the ocean carbon cycle, & the sheel building organisms that live in the oceans
Give examples of species that use calcium carbonate to build their shells
coral, oysters, lobsters & some species of plankton
Some marine organisms use …….. to make shells
Calcium Carbonate, CaCO3
What are the calcium carboante ions in the water a result of
Chemical reactions that take place when C02 dissolves in the water
When these organisms die, they sink…… , so the carbon….
to the ocean floor
enters the deep ocean
Eventually, tectonic processes of ………..&…….. transform these sediments into……
high heat & pressure
limestone
Why can carbon fluxes vary
- Biological carbon can be stored in soils in the form of dead organic matter, or returned back to the atmosphere as a form of decomposition
- depending on the nature of the soil, this process can be relatively quick (e.g a few years), or as in tundra soils, very slow
What can trigger rapid releases of carbon stores
deforestation & land use change
Mangroves as a carbon sink
Where can mangroves be found
along tropical & sub-tropical tidal coasts in Africa, Australia, Asia & the Americas
Give a statistic that shows that magroves can be a carbon sink
They are vital processors, sequestering almost 1.5 metric tonnes of carbon per hectare, every year, as CO2 is taken in during photosynthesis
What can be found in mangrove soils
- thick organic layers of litter, humus & peat, which contain high levels of carbon - over 10%
Undisturbed mangroves grow………& absorb……..
- quickly
- large amounts of carbon
Mangroves can be carbon sources
Mangroves soils are…..
anaerobic
How are mangrove stores anaerobic
- soils are submerged below high tides twice a day
How can mangroves be carbon stores
- Bacteria & microbes cannot survive without oxyden, so the decomposition of plant matter is slow, as a result, little of the carbon store can be repired back to the atmsophere & the store remains in tact
What enhances the long jevity of mangrove carbon stores
- Any plant matter trapped by tree roots tend to stay as it decomposes slowly, & may remain stored for thousands of years
However, if mangroves are drained or cleared,….
carbon can be released back to the atmosphere
Give a statistsic which describes how mangroves can be carbon sources
- If just 2% of the worlds mangroves are lost, the amount of carbon released will be 50 times the natural sequesteration rate
Why are mangroves being cleared throughout the tropical world
- tourism, shrimp farms & agriculture
How can tundra soils be carbon stores
- much of the soil in the tundra region is permanently frozen & contains ancient carbon
- microbe activity is only active in the surface layer of the soil when it thaws
- the rest of the time the roots, & dead & decayed organic matter are frozen locking any carbon into an icy store
Tundra soils contain carbon that has been trapped for…
hundreds of thousands of years
Tropical forests are huge carbon sinks, but are …….&…………………..
fragile & can disappear
Where is carbon within rainforests mainly stored
- trees, plant litter & dead matter
Describe the soil composition in rainforests
Relatively thin & lacking in nutrients, because litter layers that cover them, though very deep, decompose rapidly & the nutrients released are rapidly consumed by vegetation
Why does a carbon store in the soil not develop in the rainforest
- As the litter & dead wood decay, they are recycled very quickly
- Even carbon given off by decomposers is rapidly recycled
Give a statistic to evidence that rainforests are major carbon sinks
- Tropical rainforess absorb more atmsopeheric CO2, than any other terrestrial biome,
- accounting for 30% of global net primary production,
- although they cover just 17% of the earth’s surface
Define positive feedback
when a change leads to a strengthening of a system
Give 2 examples of positive feedback
- dying forests & warming oceans emit CO^2 which in turn warms the planet further
Define negative feedback
- when a change leads to the diminishing of a system
Give an example of negative feedback
- warmer temperatures result in increased vegetation growth which reduces atmospheric carbon
What is the goldilocks zone
- the earth is described as being in the Goldilocks zone in the solar system
- because Earth’s temperature is just right,
- the heat from the sun has warmed the planet to a point that can support life
What is the natural greenhouse effect responsible for
- For keeping our planet at a suitable temperature; the earth’s average temperature is 15 degrees
- Without the GHE, it would be -6 degrees
Explain the Natural Greenhouse Effect
- Sun enters earths atmopshere
- As the sun’s energy enters the atmosphere, clouds reflect some of it back
- only about 1/2 of it reaches the earth’s surface & lower atmosphere
Explain the Natural Greenhouse Effect
- Lower atmosphere
- this energy is able to pass through the denser gases of the lower atmosphere because of it short wavelength
Explain the Natural Greenhouse Effect
- heat energy
- Infrared is then emitted back towards space from the earth’s surface, but at a longer wavelength
- which means that it has difficulty travelling through the denser gases such as CO^2 & methane
- so the atmosphere absorbs the heat
Explain the Natural Greenhouse Effect
- warming
- this warms the lower atmosphere, the land & the sea
The natural greenhouse effect is felt the most at the….. & least at the…..
- poles
- equator
What is radiative forcing
- the difference between insolation (sunlight), absorbed by the earth
- & the energy radiated back to space
What is the current rate of the enhanced greenhouse effect
- it usually takes the planet around 5,000 years to warm up again after an ice age (by 4-7 degrees)
- the present warming rate is estimatedly 8 X faster
Nmae 3 global controls of climate
- latitude
- ocean currents
- atmospheric circulation
Name 2 local controls of climate
- albedo
- altitude
Describe the air in low pressure systems
- warm air rising
- which cools & condenses to form clouds & rain
Describe the air in high pressure systems
- cool dense air sinks
- dry clear weather
Almost all life on earth depends on….
photosynthesis
Why does almost all life on earth depend on photosynthesis
- Producers, who make their own energy by photosynthesis, form the base of the foodchain
Oceanic & Terrestrial Photosynthesis
How are carbohydrates formed
- In the cells of autotrophs (producers) by combining CO^2, water & light energy from the sun
Oceanic & Terrestrial Photosynthesis
Photosynthesis & respiration both cycle….
CO^2 & O^2 between the oceans, atmosphere & the biological world
Terrestrial Photosynthesis
CO^2 is stored in ………… that is buried in the ……
- organic matter
- soil
How does carbon move through terrestrial ecosystems
- producers
- Primary producers - plants take carbon dioxide out of the atmosphere through photosynthesis & release oxygen back into the atmosphere trhough respiration
How does carbon move through terrestrial ecosystems
- consumers
- When consumer animals eat plants, carbon from the plant beomes part of its fats & proteins
How does carbon move through terrestrial ecosystems
- organisms die
- After plant & animal death, tissues such as leaves decay further than more resistant structures such as wood
How does carbon move through terrestrial ecosystems
- waste
- Micro organisms & detritus feeders (such as beetles) feed on waste material from animals & this becomes part of these as micro-organisms
How does carbon move through terrestrial ecosystems
- decomposition
- decomposition is fastest in tropical climates with high rainfall, temperatures & oxygen levels
Why is carbon vital in soils
- organic matter is the medium by which carbon passes through the system
- & it also supports micro-organisms that
- maintain the nutrient cycle, breakdown organic matter & enhance plant growth
List some characteristics of healthy soils
- retain moisture
- contain more carbon or organic matter
- improve resilience to wetter weather
- contain many worms & other organisms
- sequester carbon
What has been the single greatest change to the balance of the carbon cycle
- burning of fossil fuels
The IPCC estimates that current rates of warming are …. times faster than the naturally changes previously experienced by the planet
8
What are the possible implications of a 2degree global rise in temp
Hydrological Cycle - precipitation
- rivers will dry up in areas of reduced precipitation,
- & contrastingly, heavy precipitation events may occur more often too
What are the possible implications of a 2degree global rise in temp
Hydrological Cycle - shifts in air pressure
- a shift of sub-tropical high pressure areas northwards will cause a 20-30% decrease in water availability in Mediterranean climate zones
What are the possible implications of a 2degree global rise in temp
Hydrological Cycle - glaciers
- small glaciers will dissappear, decreasing river discharges once they have gone e.g the Himalayas
What are the possible implications of a 2degree global rise in temp
Hydrological Cycle - humidity
- humidity levels in the atmosphere will increase, consistent with what warmer can hold
What are the possible implications of a 2degree global rise in temp
Ecosystems - extinction
- habitat land changes wil mean 10% of land species with limited adaptability will face extinction as the climate gets warmer & either wetter or drier
- rates of extinction could rise to 15-40% of all regions
What are the possible implications of a 2degree global rise in temp
Ecosystems - habitats
- biodiversity will be affected as habitats shift poleward or into deeper ocean waters or higher altiitudes
- e.g tunda biome will be affected by thawing permafrost
What are the possible implications of a 2degree global rise in temp
Ecosystems - consequences of shifting climate zones
- the shift northward of climate zones is at a rate of 6.1 km per decade
- marine diversity may be lost as fish move away from warming sea temperatures
What are the possible implications of a 2degree global rise in temp
Ecosystems - coral
- about 80% of coral reefs could be bleached
- acidification of seawater (carbonic acid) will threaten corals & the shells of marine creatures will get smaller & thinner
What are the possible implications of a 2degree global rise in temp
Ecosystems - plants
- plant changes will lag behind animal changes, as they cannot move, & they will face pests & diseases wheer there is less cold weather to kill them
What are the possible implications of a 2degree global rise in temp
Climate - Artic temperatures
- the Artic’s average temperature has already increased at twice the global average over the last 200 years
- -snow & ice will contract with the abolition of glaciers
What are the possible implications of a 2degree global rise in temp
Climate - drought
- drought will become more common in the tropics & subtropics, but some uncertainties will remain e.g El Nino
What are the possible implications of a 2degree global rise in temp
Climate - hydrological cycle
- precipitation patterns will change:
- will increase in higher latitudes & decrease in lower latitudes
What are the possible implications of a 2degree global rise in temp
Climate - storm activity
- tropical zones may experience stronger storm activity as a result of more intense heat energy & moisture in the atmosphere
- inc more intense tropical cyclones & stronger mid-latitiude westerly winds
