Carbon cycle EQ1

Question 1

biochemical carbon cycle

Answer 1

the continuous transfer of carbon from one store to another, through the process of photosynthesis, respiration, decomposition and combustion.

Question 2

carbon is exchanged among

Answer 2

the biosphere, pedosphere, lithosphere, hydrosphere, and atmosphere of the Earth

Question 3

biosphere - living things

Answer 3

• 560 billion metric tons of carbon
• 0.0012% of all carbon
• forests like the amazon

Question 4

atmosphere - air

Answer 4

• 750 billion metric tons
• 0.0017% of all carbon
• greenhouse gasses

Question 5

pedosphere - soil

Answer 5

• 0.0031% of all carbon
• organic matter

Question 6

fossil fuels

Answer 6

• 4000 billion metric tons
• 0.004% of all carbon

Question 7

hydrosphere - water

Answer 7

• 38000 billion metric tons
• 0.038% of all carbon
• sea water

Question 8

Lithosphere - crust+mantle

Answer 8

• 99.9% of all carbon

Question 9

lithosphere def

Answer 9

rigid outer part of the earth, consisting of the crust and upper mantle

Question 10

fluxe

Answer 10

action or process of flowing in or out

Question 11

carbon from the atmosphere can be sequestered into sedimentary rocks or as fossil fuels. Carbon rich sedimentary rock forms in 2 ways …..

Answer 11

1. from dead organic matterforming layers at the bottom of oceans
2. calcifying marine life

Question 12

Fluxes and Stores in the Carbon Cycle

Answer 12

• Forests
• Oceans
• Fossil fuels (eg coal)
• Sedimentary rocks (eg limestone)

Question 13

thermohaline circulation

Answer 13

the movement of ocean currents due to differences in temperature and salinity in different regions of water

Question 14

formation of shale/coal

Answer 14

1. The remains of plants and animals sank to the bottom of rivers, lakes and seas and were covered with silt and mud.
2. The remains continued to decay anaerobically and were compressed by further accumulations of dead organisms and sediment. The deeper the deposits, the more heat and pressure is exerted.
3. When organic matter builds up faster than it can decay, layers of organic carbon become oil, coal or natural gas instead of shale.

Question 15

formation of limestone

Answer 15

• Limestone is formed in ocean environments.
• Limestone started life as ocean sediments rich in calcium carbonate derived.
• The process of diagenesis occurs to convert the sediment into sedimentary rock.

Question 16

example of one of earths largest carbon stores

Answer 16

the Himalayas, which started off as ocean sediments, rich in calcium carbonate. The upfolding formed mountains which are now weathered, eroded and transported back into the ocean.

Question 17

Calcareous ooze

Answer 17

a calcium carbonate mud formed from the hard parts of the bodies of free-floating organisms.

Question 18

chemical weathering flow diagram

Answer 18

1. transfers carbon from atmosphere to hydrosphere and biosphere
2. atmospheric carbon reacts with water vapour to form weak carbonic acid
3. acid rain forms on condensation
4. rain dissolves calcium carbonate in rocks
5. produces carbon ions which get transfered into the sea

Question 19

outgassing flow diagram

Answer 19

1. release of trapped or stored gass from volcanic erruptions
2. metamorphism occurs at subduction zones where sedimentary rocks turn into metamorphic rocks under extreme pressure

Question 20

Positive feedback

Answer 20

occurs to increase the change or output: the result of a reaction is amplified to make it occur more quickly

Question 21

negative feedback

Answer 21

occurs to reduce the change or output: the result of a reaction is reduced to bring the system back to a stable state eg combination of chemical weathering and outgassing

Question 22

Carbon can be sequestered into oceans

Answer 22

Phytoplankton sequester atmospheric carbon during photosynthesis in surface ocean waters; carbonate shells/tests move into the deep ocean water through the carbon pump and through the action of the thermohaline circulation.

Question 23

Carbon moves between the atmosphere, the surface water of the ocean and the deep water through three interconnected systems known as pumps:

Answer 23

• Physical pump
• Biological pump
• Carbonate pump

Question 24

Carbon sequestration

Answer 24

the process of capturing and storing atmospheric carbon dioxide.

Question 25

physical pump

Answer 25

* Cold water holds more carbon dioxide than warm. * Cold water is denser than warm water so it sinks and is held under pressure by the weight of the water above it. * This means there is a higher concentrations of carbon dioxide in the deep water of the ocean and at higher latitudes where the water is colder.

Question 26

upwelling

Answer 26

old water is then forced to the surface in other areas of the ocean. Carbon dioxide is brought up to the surface where it might be released into the atmosphere or absorbed by phytoplankton

Question 27

downwelling

Answer 27

The thermohaline circulation moves warmer water on the surface into cooler areas of the world. As the warm water cools, it absorbs more carbon dioxide and sinks to the deeper waters

Question 28

biological pump

Answer 28

* Carbon dioxide can be consumed by phytoplankton, through the process of photosynthesis. * Phytoplankton are at the bottom of the food chain for marine animals so the carbon is transferred up the chain. * Respiration releases some carbon dioxide back into the atmosphere, though most of this carbon remains in surface waters and then is reabsorbed by phytoplankton. * When marine animals die they fall to the ocean floor, where the carbon stored in their bodies is transferred to the deep ocean.

Question 29

carbonate pump

Answer 29

* Chemical weathering can wash carbon-based molecules into the sea through river systems. * Here, they react with carbon dioxide dissolved in the water to form calcium carbonate, which is used by some marine organisms to make shells. * When these marine organisms die, they sink to the bottom of the ocean where they create a sediment rich in calcium carbonate (sedimentation). * These form limestone.

Question 30

terrestrial primary producers

Answer 30

Terrestrial primary producers sequester carbon during photosynthesis; some of this carbon is returned to the atmosphere during respiration by consumer organisms.

Question 31

Biological carbon

Answer 31

carbon can be stored as dead organic matter in soils, or returned to the atmosphere via biological decomposition over several years.

Question 32

soil

Answer 32

* Active soil microbes respire CO2 quickly * If plants transfer more carbon into soil than is released via soil respiration, more carbon will get stored in the soil * Microbes need energy: it comes from burning sugars, which in turn releases CO2. * This CO2 can be used by plants covering the soil surface for photosynthesis and/or drift up to the air to join other CO2 molecules in the atmosphere.

Question 33

solar radiation

Answer 33

* Light energy from the sun (short wave) * Absorbed by earth and re-emitted as longwave energy (heat) * Some escapes the atmosphere, but some is absorbed by greenhouse gases, warming the earth and its atmosphere

Question 34

the enhanced greenhouse effect

Answer 34

If we add more greenhouse gases to the atmosphere, more of that longwave radiation will be trapped (and less will escape) The planet will warm up more than it should do

Question 35

Shortwave radiation

Answer 35

* 49.1% of incoming solar radiation is absorbed by the Earth * 19.6% absorbed by the atmosphere * 31.3% is reflected into space from the Earth’s surface and clouds

Question 36

Longwave radiation

Answer 36

* 390 Wm2 (energy) radiated from the Earth as longwave radiation * 40Wm2 goes straight out to space

Question 37

The energy budget is balanced

Answer 37

Incoming energy equals outgoing energy, but the greenhouse gases ensure that the lower atmosphere, land and sea is warmed, albeit with a range of temperatures from tropical to polar. Without greenhouse gases the Earth’s average surface temperature would be -6oC rather than +15oC

Question 38

human implications of fossil fuels

Answer 38

Human activity has transferred considerable amounts of carbon from fossil stores, where fluxes are very slow, into the fast category, significantly disturbing the climate cycle. Whereas after an ice age it usually took the planet 5000 years to warm up again (by 4-7oC), the present warming rate is estimated to be eight times faster.

Question 39

climate

Answer 39

* Changes in the thermohaline circulation - melting glaciers → reduced salinity → reduced downwelling * Dry areas are likely to get drier and wetter areas are likely to see increased rainfall * Rainfall patterns will become unpredictable * Extreme weather events such as storms will increase.

Question 40

hydrological system

Answer 40

* Glacial areas - Ice sheets and glaciers are melting which increases the risk of flooding for glacier-fed rivers. * Meltwater adding to the oceans → sea level rise * Increased precipitation → more floods

Question 41

ecosystems

Answer 41

* Plants that are sensitive to temperature have declined → biodiversity in some biomes decreasing * Areas of permafrost are no longer experiencing long seasons of frozen ground → impacts vegetation that is adapted to these conditions. * Species migration to find correct conditions for survival * Increased risk of extinction * Sea level rise → loss of ecosystems in low lying regions * Ocean acidification → coral bleaching

Question 42

Positive Feedback in the Carbon Cycle

Answer 42

Permafrost thawing due to global warming: 1. Higher temperatures thaw permafrost in tundra regions. 2. Organic material in permafrost decomposes → releases CO₂ and CH₄. 3. These are potent greenhouse gases → more heat trapped in atmosphere. 4. Leads to further warming and more permafrost melt. Result: A self-reinforcing loop accelerating climate change.

Question 43

Negative Feedback in the Carbon Cycle

Answer 43

CO₂ fertilisation effect: 1. Higher CO₂ concentrations stimulate plant growth (photosynthesis). 2. Plants absorb more CO₂ from the atmosphere. 3. This reduces atmospheric CO₂ levels over time. Result: Helps counteract the initial rise in CO₂ – restoring balance.