Carbon : 1.1 - 1.4

Question 1

1.1 summary

Answer 1

Most global carbon is locked in terrestrial stores as part of the long term geological cycle.

Question 2

Levels of CO2 has corresponded closely

Answer 2

With temperature over the past 800k years..

Question 3

Fossil fuels are a

Answer 3

prime example of carbon which is stored underground

Question 4

The formation of coal, where a sedimentary layer, rich in organic carbon, is buried deep underground and thus

Answer 4

turned into coal after a long time period under intense heat and pressure.

Question 5

Formation of limestone is an example of carbon stored in the ocean.

Answer 5

occurs due to ca+ eroded from rocks due to chemical weathering from rivers. Ca+ ions are then transported into the ocean, where they react with carbonate dissolved in water to firm calcium carbonate, which deposits in the seabed and forms limestone

Question 6

Uplifting of Himalayas which began 50Mil years ago changed the level of carbon in the atmosphere, as it

Answer 6

brought more rock exposed to the atmosphere, adding more carbon to slow carbon cycle.

Question 7

Types of carbon stores 1

Answer 7

• Crustal/ terrestrial geological - sedimentary rocks, slow cycling thousands year
• Terrestrial soil: from breakdown of organic matter in plant material, depends on climate
• Deep oceanic - dissolved inorganic carbon stored at great depths, very slowly cycled

Question 8

Types of carbon stores 2

Answer 8

Surface oceanic - rapid exchanges with the atmosphere dissolving in water or phytoplankton
- Atmospheric - co2 and ch4 store carbon as GHG which have a lifetime of 100yrs
- Terrestrial ecosystems: co2 taken from atmosphere by plants/ trees photosynthesis

Question 9

Interlinking Cycles

Answer 9

• volcanic outgassing is when co2 in mantle vented to atmosphere.
• Volcanic rock also forms part of rock cycle - where rock breaks down, including potentially creating acidic rainwater to help break the rock down even more with chemical weathering.
• Sediment also then relies on the watre cycle - with it being transported, before eventually being subducted

Question 10

Sedimentary (layers) carbonate rocks

Answer 10

• E.g. limestone, high conc of calcium carbonate
• Formed from shells and skeletons of dead coral and other marine creatures, carbon extracted form ocean water as living marine phytoplankton absorb carbon through photosynthesis - carbon sequestered in the shell
• Accumulation and cement action of shells under heat and pressure forms limestone under ocean floor
• Tectonics fold and uplift limestone from ocean bed to form mountain ranges
• Subsequently chemically weathered by carbonic acid, return back to current oceans

Question 11

Hydrocarbon formation

Answer 11

• Remains of living organic material from 300 million years ago decay under anaerobic conditions
• Form chains of hydrogen (13%) and carbon (87%) bonds, which is stored in the pore spaces of clastic sedimentary basins
• Gas is a by product during this process, migrating upwards through shale until it meets a caprock
• Coal forms from remains of trees, ferns and land based plants
• Organic material in swamps starts as peat, but heat and pressure convert it to coal

Question 12

Principle 1

Answer 12

• There are two types of water – warm tropical water (often nearer the surface), cold polar water (much deeper), and they don’t mix

Question 13

Principle 2

Answer 13

• Colder water can hold more gas than warm water
• If colder, gas molecules move slower, so they diffuse out of solution more slowly – gas tends to stay.
• Molecules at room temperature are hotter, moving faster - Less gas can be dissolved in warmer room temperatures

Question 14

Principle 3

Answer 14

• Warm tropical water moves towards the poles, and evaporates, leaving saltier water, and colder water, which then sinks, able to hold more CO2.

Question 15

Principle 4

Answer 15

pumping of co2 water forces deep water that’s already there to find somewhere else to go, but this movement is determined by landmasses, so cold water flows around the world neat to Antarctica, gets recharged by extra cold Atlantic water, therefore southern ocean is a big carbon sink - 25% of co2 diffusion. Splits in the south ocean - one track to Indian Ocean and back round Antarctic, one to Pacific Ocean to rise at equator, so warm water rises in Indian oceans and pacific

Question 16

Physical cycle + pump

Answer 16

When the ocean moves dissolved CO2

• Diffusion: ocean absorbs co2 which is dissolved into the ocean, downwelling currents move water from surface ocean to deep ocean
• Physical pump = cold polar water absorbs even more co2, increasing salinity, so it sinks (downwelling), surface winds allow warm water from tropical to take place of sunken cold water, allowing even more diffusion

Question 17

Solubility cycle + carbonate pump

Answer 17

When the ocean absorbs CO2

• Hydrogen ions break carbon acid apart, forming bicarbonates, organisms use these to make shells/ skeletons carbonates.
• Carbonate pump = as organisms die, carbonate sediment is dragged down / skinks to the ocean/ sea bed is gradually transformed to rocks e.g. limestone which can remain there for geological epochs.

Question 18

Biological cycle + pump

Answer 18

When phytoplankton in the ocean sequester CO2

• Photosynthesis- co2 becomes organic matter

Biological pump: as organisms die, dead cells/ shells sink: carbon is transported from surface too intermediate deep oceans. Decay releases co2 into intermediate deep water, instead of being in surface water where it could vent into the atmosphere

Question 19

Physical Pump

Answer 19

Cold (polar) water absorbs even more Co2, increasing salinity, so it sinks (downwelling)
Surface winds allow warm water from the tropics to take the place of sunken cold water, allowing even more diffusion

Question 20

Carbonate pump

Answer 20

As organisms die, carbonate sediment is dragged down / sinks to the ocean / sea bed is gradually transformed to rocks, e.g. limestone, which can remain there for geological epochs

Question 21

Biological Pump:

Answer 21

As organisms die, dead cells, she,LVS sink : carbon is transported from surface to intermediate/ deep oceans. Decay releases co2 into intermediate/ deep water, instead of being surface water it could vent in the atmosphere.

Question 22

How does thermohaline circulation work

Answer 22

• two types of water, warm tropical and cold polar water, warm is nearer to surface while cold polar is deeper. They don’t mix
• colder water generally holds more gas than warmer water, because gas molecules in cold water move slow, thus diffuse out at a slower rate. So more gas can be dissolved in cold water than room temp water
• warm water moves towards poles and evaporates, leaving colder, more saline water, which can contain more co2
• pumping of cold water with co2 forces deep water to travel elsewhere, this is dictated by landmasses around the world. As a result of this, cold water flows around the world to Antarctica, and is recharged by extra cold Antarctican water, so south ocean cintauns Marge deep, cold water stores with 25% ocean carbon diffusion.

Question 23

Photosynthesis

Answer 23

• Plants use light energy and convert into chemical energy for any potential future growth by synthesising carbon dioxide and water.
• The chemical energy is stored as carbohydrates such as sugars.
- plants use this energy when they do not gave access to light and do so by utilising the free oxygen molecules which releases the carbon

Question 24

Terrestrial sequestration (land based absorption of carbon)

Answer 24

• Photosynthesis converts carbon in atmosphere into carbs for energy
• Carbon locked up in leaves, shoots, roots and bark and then transferred into soil upon decomposition by soil biota
• If peat conditions are dry aerobic, decay happens and carbon returns to atmosphere
• If peat conditions are wet anaerobic, carbon can’t decay, so co2 locked away as dark organic matter in peatlands/peatbogs- but methane emissions increase
• If peat conditions are too wet - waterlogged, anaerobic de nitrifying bacteria interfere with plant growth = less co2 absorption

Question 25

Ocean sequestration (ocean based absorption of carbon)

Answer 25

• Photosynthesis occurs in phytoplankton which are subsequently eaten by larger marine organisms
• As plankton or organisms die, dead cells/ shells skink carbon is transported from surface to deep oceans
• Decay releases co2 into intermediate deep water rather than surface where it could vent into atmosphere
• Also ocean hold onto co2 as a dissolved gas

Question 26

In waterlogged landscapes:

Answer 26

Dead vegetation builds up, but can only partially decay (as conditions are anaerobic) which preserves the carbon, and this becomes a large store

Question 27

peat formation

Answer 27

Dead veg builds up but can’t fully decay due to anaerobic conditions, carbon then preserved. With heat pressure peat turns into lignite, coal and anthracite, as there is increased carbon, there will be increased burn time

Question 28

Peatlands cover

Answer 28

Around 4 million km^2 or 3% of the worlds land area
More in the northern hemisphere

Question 29

Worlds largest tropical peatland discovered in

Answer 29

Remote Congo swamps, estimated to store the equivalent of three years worth of total fossil fuel emissions

Question 30

Human causes disasters with peatlands

Answer 30

In Indonesia, country with most peatland, intentional deforestation and drainage for palm oil led to wilderness in 2015, emitting 23% of Indonesia’s total carbon emissions.
- deforestation of peatlands for palm oil = higher forest fire risk
- created a new season called the haze season
- Causes lots of deaths due to lung cancer + asthma
- burning of land cause displacement of people and villages

Question 31

Peatlands positives

Answer 31

• Filter heavy metal toxins and purify water
• Provide home for rare wetlands species
• Hold toxic unregulated gases from industrial era
• Holds 1/3 of world’s organic soil carbon!
- Peatlands only cover 3% of world’s land surface, but store twice as much carbon as all of Earth’s living forests

Question 32

Why is there uncertainty about peatlands?

Answer 32

• How much carbon is locked up in peatlands and permafrost? Is it really considerably more than trees / fossil fuels?
• Does draining peatlands improve, or reduce carbon emissions? It depends on how far you go… (waterlogged peatlands can be worse for plant growth and methane emissions), whereas dry peatlands are worse for CO2 emissions.
• What happens if we burn, degrade peatlands? Will it trigger positive feedback processes that would cause even more carbon to be released from storage?
What is the rate of restoration of peatlands? Will that increase biological carbon storage again?

Question 33

Why is there uncertainty about permafrost?

Answer 33

• How much has permafrost has warmed? How much methane has been released? Is there more to be released?
• How much industrialisation has happened? How much will the Paris agreement reduce greenhouse gases?
• How deep has the active layer melted? Is some carbon / methane still locked up? Could more be released?
• Does it matter that CH4 is more potent GHG than CO2?

Question 34

What happens if peatlands are drained?

Answer 34

Organic matter begins to decay, which creates co2, and peatland becomes more susceptible to burning

Question 35

Studies show

Answer 35

Heating the peat doesn’t affect the level of carbon within the peatland.

Question 36

Define thermohaline circulation

Answer 36

Thermohaline circulation is an ocean current that produces both vertical and horizontal circulation of cold and warm water around the worlds oceans, in addition - atmospheric circulation creates large currents in the oceans which transfer water from warmer tropical areas of the world to the colder polar regions.

Question 37

In the THC, rate of circulation is slow:

Answer 37

takes around 1000 years for any cubic metre of water to travel around the entire system. Warm surface waters depleted of co2 and nutrients therefore the foundation of the planets food chain depends on cool nutrient rich water which support algae to grow

Question 38

Rate of absorption of co2 into ocean depends on

Answer 38

ocean temperatures, colder water = more absorbed. Therefore, as ocean temps increase, ocean absorb less co2, positive feedback cycle which would increased lead to further CC

Question 39

Two types of ways for formation of sedimentary rocks

Answer 39

• Himalayas negative feedback cycles = bio pump
  Carbon derived from plants and animal in coal, etc = carbonate pump