Carbon cycle unit 4-7 practice

Question 1

Define the carbon cycle

Answer 1

The carbon cycle is a biochemical cycle by which carbon moves from one part of the planet to another

Question 2

State the five main carbon stores

Answer 2

Biosphere (living parts)

Atmosphere (gases)

Hydrosphere (carbon in water)

Lithosphere (carbon in rocks)

Cryosphere (carbon in ice)

Question 3

What are the three main processes in the slow carbon cycle?

Answer 3

Chemical weathering (carbonation)

Carbon storage (sequestration) on ocean floor

tectonic processes and volcanic activity

Question 4

Summarise the chemical weathering of the slow carbon cycle

Answer 4

Atmospheric carbon is dissolved in water vapour and forms carbonic acid. Precipitation is naturally acidic (carbonic acid).

Carbonic acid reacts with rocks containing calcium carbonate (limestone) through carbonation weathering and creates calcium bicarbonate

Calcium bicarbonate is soluble in water and is carried in solution by runoff and percolating water

Soluble calcium carbonate is transferred to the ocean via runoff

Question 5

What’s the pH of neutral water?

Answer 5

7

Question 6

What’s the pH of acid rain?

Answer 6

anything with a pH of 5.6 or below

Question 7

How do oceans store carbon?

Answer 7

At the bottom of oceans large amounts of dissolved inorganic carbon accumulate, known as carbon sequestration to form carbonate sediments. Some of this sediment will be from bicarbonate created by carbonation weathering.

Question 7

How is calcium bicarbonate transferred to oceans?

Answer 7

Rivers, throughflow and groundwater transport calcium bicarbonate to the oceans

Question 8

How is carbon used by marine organisms?

Answer 8

Marine organisms such as plankton and shellfish rely on carbonate ions to make their shells.

Question 9

What happens to the carbon stored on the ocean floor?

Answer 9

In subduction zones at convergent plate boundaries will force carbonate rich sediments into magma which may result in volcanic eruptions, emitting CO2 back into the atmosphere by volcanoes.

Question 10

Name the three main processes of the fast carbon cycle

Answer 10

Diffusion of CO2 between atmosphere and oceans

Photosynthesis, respiration and decomposition

Combustion of forest fires and fossil fuels

Question 11

Describe the physical inorganic pump which carbon diffused in oceans follows

Answer 11

CO2 moves around oceans by thermohealene currents which form due to variations in ocean temp and salinity

Question 12

Describe how thermohaline currents move carbon in oceans (2 points)

Answer 12

Carbon can be transferred from the surface to the deep oceans in areas wgere cold dense surface waters sink through downwelling - usually in polar regions (North Atlantic Drift)

Carbon can be transferred from deep oceans to the surface through upwelling - usually in equatorial regions

Question 13

Describe the biological (organic) pump for carbon movement in the ocean for fast carbon cycle- full description

Answer 13

CO2 is diffused into ocean surfaces

Phytoplankton photosynthesise and used the diffused co2 storing it in new biomass

as part of the ocean food chain phytoplankton are eaten by zooplankton which in turn are eaten by other marine organisms, passing the carbon in carbohydrates

When organisms respire they release co2, some of which will pass back to the atmosphere

marine organisms die and sink to the seafloor adding to the carbon rich sediment on the ocean bed (sequestriation)

over millions of years organic rich sediment can form fossil fuels (oil and gas) - long term carbon cycle

Question 14

Describe photosynthesis through carbon movement in the fast carbon cycle

Answer 14

photosynthesis is a biochemical process operating in plants that converts CO2 and water into glucose and oxygen.

Question 15

Where is photosynthesis highest around the world?

Answer 15

High - tropics 30 degrees north and south of the equator

Moderate - areas beyond the tropics 60 degrees north and south

Low - Polar regions - lots of sun but no water

Question 16

Describe the movement of carbon through respiration in the fast carbon cycle

Answer 16

respiration involves the release of energy from glucose so that all other processes needed for life can happen. co2 is released back into the atmosphere as a by-product of respiration.

Question 17

Describe decomposition as a carbon movement in the fast carbon cycle

Answer 17

plants and animals die and decompose. This process of decomposition carried out by organisms known as detritivores such as earthworms aid decomposition as they feed on dead organic matter. Decomposition releases co2 and methane back into the atmosphere.

Question 18

What percentage do wildfires contribute to greenhouse gas emissions?

Answer 18

20%
Lincolnshire 2020
Australia 2019

Question 19

Define a biome

Answer 19

a biome is an ecological community whose global distribution corresponds with climatic regions of the earth

Question 20

Describe the distribution and climate of tropical rainforests?

Answer 20

Equatorial regions such as the Amazon and Malaysia

Wet and warm

Question 21

Describe the distribution of temperate grasslands and their climate?

Answer 21

high altitude regions 30 - 60 degrees north and south of the equator. Predominantly to the north of the tropic of cancer. Chine, Argentina, Middle-East

Climate varies

Question 22

State the size of the carbon stored in a tropical rainforest?

Answer 22

2kg carbon annually per metre squared.

Trees store twice as much as they release - 200% efficiency

Up to 5000 tonnes of carbon per hectare per year

Question 23

How much carbon does a primary forest store per hectare?

Answer 23

300

Question 24

How much carbon is stored in a temperate grassland compared to a tropical rainforest?

Answer 24

compared to tropical rainforests where NPP averages around 2kg per metre squared per year, temperature grasslands store around 600 grams per metre squared per year

Question 25

What diagram must be drawn in an essay for carbon stores in either grassland or tropical rainforests?

Answer 25

Gershmehl diagram

Question 26

State the stores of carbon in a tropical rainforest and a temperate grassland

Answer 26

Biomass

Litter

Soil

Question 27

State the three influences on a carbon store in either tropical rainforest or temperate grassland

Answer 27

temperature
precipitation
light

Question 28

Name three ways humans change the use of land in either TR or Grasslands

Answer 28

Deforestation (Borneo)

Afforestation (Brazil)

Agricultural activity (Dust Bowl)

Question 29

Describe the distribution of peat formation

Answer 29

Peat is mostly found in the northern hemisphere including parts of north America and northern Europe. countries include Scotland, Ireland, Denmark, Russia.

Question 30

What are the three main types of peatlands in the UK?

Answer 30

Fen Peatlands - where groundwater meets the surface

Blanket peatlands - occur on flat hill tops where rainfall is high

Raised Bogs - occurs in valley bottoms where soils saturated

(Whixhall Moss)

Question 31

How does carbon accumulate through peat formation?

Answer 31

Peat forms in waterlogged areas, lacking in oxygen and where the water is acidic. In these conditions, decomposition is restricted so that dead organic matter doesn’t decompose. Over thousands of years peat accumulates at the rate of about 1mm per year. Consequently, carbon is preserved and makes up 50% of the dead organic matter.

Question 32

What does sphagnum moss do?

Answer 32

Holds 20x its own weight in water and makes the water acidic - 4.5 which means theres a potential for hydrogen ions

Question 33

State the two ways the carbon store in peat is reduced

Answer 33

peat extraction and drainage

Question 34

Discuss human activities which reduce carbon stored in peat

Answer 34

Cutting peat and burning as a fuel

Cutting peat and use in horticulture

Drainage of peat and use for agriculture of forestry

Question 35

State three ways a peatland can be restored and managed

Answer 35

Blocking drainage channels

Removing invasive shrub and tree species

Re-seeding damage areas with sphagnum moss.

Question 36

What are the causes of recent increases in the atmospheric carbon store. What did IPCC say?

Answer 36

According to the Inter-governmental panel on climate change (IPCC) in so23, ‘human activities, principally through emissions of greenhouse gases, have unequivocally caused global warming, with global surface temperatures reaching 1.1 degrees above 1850-1900 in 2011-2020.

Question 37

Give a specific cause for the increase in atmospheric carbon

Answer 37

linked to increased concentrations of greenhouse gases, namely carbon dioxide and methane. Methane is the second most important greenhouse gas. It is 25x more potent than CO2.

Question 38

Which graph represents the increase in average global temperature?

Answer 38

The Hockey Stick Graph by Mann, Bradley and Hughes in 1999. The graph shows the rise in global temperatures since the industrial revolution.

Question 39

Define the energy budget

Answer 39

The balance between incoming radiation from the sun and outgoing radiated heat plus reflected radiation from the sun.

Question 40

Describe the relationship between recent increases in the atmospheric carbon store and the energy budget

Answer 40

Greenhouse gases absorb heat energy released from the Earth’s surface, retaining heat.

Changes to patterns and levels of precipitation/extreme weather events - more convectional rainfall

Sea level rise and acidification of oceans

Question 41

State the impacts of recent increases in the atmospheric carbon store on the water cycle and oceans

Answer 41

Collectively, we have had 8/10 of the warmest year since 2002 and 7/10 wettest years since 1998

Flooding (River Fargo)
Extreme rain (Boscastle)
Drought (1976 UK)
Forest fires (Lincolnshire 2020)

Question 42

What’s a feedback system?

Answer 42

A feedback system is a series of responses that change the ‘steady-state equilibrium’ of a system.

Positive feedback - increases or amplifies the initial change

Negative feedback - stops or reverse the initial change

Question 43

Name the four types of feedback loops

Answer 43

Methane feedback

Cryosphere feedback

Marine carbon feedback

Terrestrial ecosystem feedback

Question 44

Describe the methane feedback loop (5 steps)

Answer 44

High levels of greenhouse gases in the atmosphere cause global temperatures to increase

Increasing temperatures cause permafrost to thaw

Thawing exposes previously frozen organic matter to decay

As organic matter decays it releases CO2 into the atmosphere

Atmospheric CO2 and methane levels increase

Question 45

State the cryosphere feedback loop (4 steps)

Answer 45

Increase in atmospheric temps

Melting of sea ice and glaciers

Reduced albedo of earths surface

Increased insolation absorption

Question 46

State a marine feedback loop (7 steps)

Answer 46

Warmer ocean water absorbs less atmospheric carbon by diffusion

There is less carbonate ions for shell production and for producers to survive on

Impacts entire food chain

Kills marine life

Decomposition

Releases CO2 and CH4

Greenhouse effect

Global warming

Question 47

Define ocean acidification

Answer 47

As oceans absorb CO2 by diffusion, surface water becomes more acidic. Carbonic acid is created when water diffuses with carbon.

Question 48

Need to do a terrestrial feedback loop!

Answer 48

Deforestation of tropical rainforests (Borneo)

Deforested trees release CO2 - IPCC statement

Increaseses greenhouse conc

Question 49

Does the carbon or water cycle affect the plant most?

Answer 49

Carbon cycle seen as most effects of the water cycle is a result of the carbon cycle.