Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

IB Biology > 4.3 Carbon Cycling > Flashcards

4.3 Carbon Cycling Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What is the carbon cycle?

A

The carbon cycle is a biogeochemical cycle whereby carbon is exchanged between the different spheres of the Earth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the four spheres?

A

The four spheres are the atmosphere (air), lithosphere (ground), hydrosphere (water / oceans) and biosphere (living things)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

In what 4 forms can carbon be exchanged?

A

atmospheric gases
oceanic carbonates
organic materials
non-living remains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

In what form can carbon be found in atmospheric gases?

A

mainly carbon dioxide (CO2), but also methane (CH4)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

In what form can carbon be found in atmospheric gases?

A

mainly carbon dioxide (CO2), but also methane (CH4)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

In what form can carbon be found in oceanic carbonates?

A

including bicarbonates dissolved in the water and calcium carbonate in corals and shells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

In what form can carbon be found in organic materials?

A

including the carbohydrates, lipids and proteins found in all living things

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

In what form can carbon be found in living remains?

A

as detritus and fossil fuels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How do autotrophs convert inorganic compounds?

A

Autotrophs, such as all plants and algae, convert inorganic carbon dioxide into organic compounds via photosynthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What organic compounds is CO2 converted into via photosynthesis?

A

These organic compounds include the carbohydrates, lipids and proteins required by the organism for survival

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What levels of CO2 should autotrophs have?

A

Since autotrophs use carbon dioxide for photosynthesis, the levels of carbon dioxide within the organism should always be low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

In which sphere should there be a higher conc of CO2?

A

In other words, carbon dioxide should always be at a higher concentration in the atmosphere (or water)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does the differing concentration of CO2 ensure?

A

This concentration gradient ensures that carbon dioxide will passively diffuse into the autotrophic organism as required

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does diffusion of CO2 differ in aquatic and terrestrial autotrophs?

A

In aquatic producers, CO2 can usually diffuse directly into the autotroph; whereas in terrestrial plants, diffusion occurs at stomata

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What do all organisms produce to survive?

A

All organisms may produce the chemical energy (ATP) required to power metabolic processes via the process of cell respiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does cell respiration involve?

A

Cell respiration involves the breakdown of organic molecules (e.g. sugars) and produces carbon dioxide as a by-product

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is a result of respiration? How is this useful?

A

The build up of CO2 in respiring tissues creates a concentration gradient, allowing it to be removed by passive diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

In autotrophs, what may happen in relation to these two processes?

A

In autotrophs, the uptake of CO2 by photosynthesis may at times be balanced by the production of CO2 by respiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is it called when rate of photosynthesis=rate of respiration?

A

This is known as the compensation point, at which the net carbon dioxide assimilation is zero (intake = output)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What determines the level of carbon dioxide in the environment? (2 relating to net ___)

A

If there is more net photosynthesis than cell respiration occuring in the biosphere, atmospheric carbon dioxide levels should drop

If there is more net respiration than overall photosynthesis occuring, atmospheric carbon dioxide levels should increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What happens when Co2 dissolves in water?

A

Carbon dioxide dissolves in water and some of it will remain as a dissolved gas, however the remainder will combine with water to form carbonic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Give equation for CO2 dissolving in water

A

CO2 + H2O ⇄ H2CO3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What happens to carbonic acid + equation?

A

Carbonic acid will then dissociate to form hydrogen carbonate ions (H2CO3 ⇄ HCO3– + H+)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What causes the change in pH of the ocean?

A

This conversion (H2CO3) also releases hydrogen ions (H+), which is why pH changes when CO2 is dissolved in water (> acidic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What do autotrophs absorb in relation to ocean CO2?

A

Autotrophs absorb both dissolved carbon dioxide and hydrogen carbonate ions and use them to produce organic compounds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What can hydrogen carbonate ions come into contact with in the ocean?

A

When the hydrogen carbonate ions come into contact with the rocks and sediments on the ocean floor, they acquire metal ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What can the contact between HCO3- ions with rocks and sediments form?

A

This commonly results in the formation of calcium carbonate and the subsequent development of limestone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How can CaCO3 be formed in oceans?

A

Living animals may also combine the hydrogen carbonate ions with calcium to form calcium carbonate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the use of calcium carbonate in aquatic environments?

A

This calcium carbonate forms the hardened exoskeleton of coral, as well as forming the main component of mollusca shells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What happens to the calcium carbonate when an organism dies?

A

When the organism dies and settles to the sea floor, these hard components may become fossilised in the limestone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are methanogens?

A

Methanogens are archaean microorganisms that produce methane (CH4) as a metabolic by-product in anaerobic conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Where can methanogens be found?

A

Anaerobic conditions where methanogens may be found include:

Wetlands (e.g. swamps and marshes)
Marine sediments (e.g. in the mud of lake beds)
Digestive tract of ruminant animals (e.g. cows, sheep, goats)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What do methanogens produce and how?

A

Methanogens produce methane from the by-products of anaerobic digestion, principally acetic acid and carbon dioxide:

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

How is acetic acid used in methanogens? give equation

A

Acetic acid → Methane and Carbon Dioxide (CH3COO– + H+ → CH4 + CO2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

How is CO2 and H2O used by methanogens? Give equation

A

Carbon Dioxide and Hydrogen → Methane and Water (CO2 + 4 H2 → CH4 + 2 H2O)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What happens to released methane?

A

Methane may either accumulate under the ground or diffuse into the atmosphere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

How may natural gas be formed?

A

When organic matter is buried in anoxic conditions (e.g. sea beds), deposits of methane (natural gas) may form underground

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What may be increasing global levels of methane?

A

Rising global numbers of domesticated cattle may be increasing the levels of methane being released into the atmosphere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

How long does methane persist in the atmosphere?

A

When methane is released into the atmosphere as a result of anaerobic reactions, it only persists for ~12 years

40
Q

Why are methane levels in the atmosphere are not very large, even though significant quantities are being produced ?

A

Methane will be naturally oxidised to form carbon dioxide and water (CH4 + 2 O2 → CO2 + 2 H2O)

41
Q

What is methane oxidised to? Give equation

A

Methane will be naturally oxidised to form carbon dioxide and water (CH4 + 2 O2 → CO2 + 2 H2O)

42
Q

How are nutrients recycled in soil?

A

In many soils, saprotrophic bacteria and fungi will decompose dead organisms and return nutrients to the soil for cycling

43
Q

What does the process of decomposition require?

A

This decomposition process requires oxygen (cell respiration is required to fuel digestive reactions)

44
Q

Where is aerobic decomposition not possible?

A

Waterlogged regions may lack oxygenated air spaces within the soil and thus possess anaerobic conditions

45
Q

What does anaerobic respiration form?

A

Anaerobic respiration by organisms in these regions produces organic acids (e.g. acetate), resulting in acidic conditions

46
Q

What do the acidic conditions (in soils) prevent?

A

Saprotrophic bacteria and fungi cannot function effectively in anaerobic / acidic conditions, preventing decomposition

47
Q

What is formed due to the incomplete decomposition of organic matter?

A

Since the organic matter is not fully decomposed in waterlogged soils, carbon-rich molecules remain in the soil and form peat

48
Q

What happens when peat is compressed?

A

When deposits of peat are compressed under sediments, the heat and pressure force out impurities and remove moisture

49
Q

How is coal produced from peat?

A

The remaining material has a high carbon concentration and undergoes a chemical transformation to produce coal

50
Q

In general, how is oil and natural gas formed?

A

Oil (i.e. petroleum) and natural gas form as the result of the decay of marine organisms on the ocean floor

51
Q

In aquatic ecosystems, what is deposited upon organic matter to start the formation of oil/natural gas?

A

Sediments (e.g. clay and mud) are deposited on top of the organic matter, creating anoxic conditions that prevent decomposition

52
Q

What is a result of the material compaction in aquatic ecosystems?

A

As a result of the burial and compaction, the organic material becomes heated and hydrocarbons are formed

53
Q

What do the hydrocarbons form? (aquatic ecosystem)

A

The hydrocarbons form oil and gas, which are forced out of the source rock and accumulate in porous rocks (e.g. sandstone)

54
Q

How long does it take for various fossil fuels to be formed?

A

The formation of fossil fuels (coal, oil and gas) takes place over millions of years, making them a non-renewable energy source

55
Q

What is a combustion reaction? (conditions)

A

When organic compounds rich in hydrocarbons are heated in the presence of oxygen, they undergo a combustion reaction

56
Q

What type of reaction is combustion?

A

This reaction is exergonic (produces energy) and releases carbon dioxide and water as by-products

57
Q

What happens to the carbon dioxide produced by combustion?

A

The carbon dioxide is typically released into the atmosphere, increasing the concentration of the gas in the air

58
Q

What happens to organic compounds when they’re compacted for millions of years?

A

Organic compounds can become rich in hydrocarbons when compacted underground for millions of years

59
Q

What does compaction trigger in order to make organic matter rich in hydrocarbons?

A

The heat and pressure over time triggers a chemical transformation that results in the compaction of the organic matter

60
Q

What is produced by the compaction of organic matter?

A

The resulting products of this process are fossil fuels (coal, oil and natural gas)

61
Q

Why are fossil fuels considered non-renewable?

A

Because this geological process takes millions of years to occur, fossil fuels are a non-renewable energy source

62
Q

What is another way to manufacture fuels, reducing dependence on fossil fuels?

A

An alternative to relying on fuels produced by geological processes is to manufacture fuels from biological processes

63
Q

What do living organisms produce which are useful for fuels?

A

Living organisms produce hydrocarbons as part of their total biomass (either for use or as a waste product)

64
Q

What can be done with the hydrocarbons produced by organisms?

A

These hydrocarbons can be extracted and purified to produce an alternative fuel source (e.g. bioethanol and biodiesel)

65
Q

Why is biomass considered a “better” fuel source?

A

Provided new raw materials are provided and waste products are removed, this source of energy is renewable

66
Q

What are carbon fluxes?

A

Carbon fluxes describe the rate of exchange of carbon between the various carbon sinks / reservoirs

67
Q

What are the 4 main carbon sinks?

A

There are four main carbon sinks – lithosphere (earth crust), hydrosphere (oceans), atmosphere (air), biosphere (organisms)

68
Q

What does the rate of carbon exchange depend on?

A

The rate at which carbon is exchanged between these reservoirs depends on the conversion processes involved

69
Q

What is the role of photosynthesis in the carbon cycle?

A

removes carbon dioxide from the atmosphere and fixes it in producers as organic compounds

70
Q

What is the role of respiration in the carbon cycle?

A

releases carbon dioxide into the atmosphere when organic compounds are digested in living organisms

71
Q

What is the role of decomposition in the carbon cycle?

A

releases carbon products into the air or sediment when organic matter is recycled after death of an organism

72
Q

What is the role of gaseous disolution in the carbon cycle?

A

the exchange of carbon gases between the ocean and atmosphere

73
Q

What is the role of lithification in the carbon cycle?

A

the compaction of carbon-containing sediments into fossils and rocks within the Earth’s crust (e.g. limestone)

74
Q

What is the role of combustion in the carbon cycle?

A

releases carbon gases when organic hydrocarbons (coal, oil and gas) are burned as a fuel source

75
Q

Is it possible to measure the size of carbon sinks?

A

NO
It is not possible to directly measure the size of the carbon sinks or the fluxes between them – instead estimates are made

76
Q

How are global carbon fluxes measured?

A

Global carbon fluxes are very large and are therefore measured in gigatonnes (1 gigatonne of carbon = 1 billion metric tonnes)

77
Q

Are carbon flux calculations accurate?

A

Because carbon fluxes are large and based on measurements from many different sources, estimates have large uncertainties

78
Q

What does estimating carbon fluxes require?

A

estimating carbon fluxes requires an understanding of the factors that can affect the exchange of carbon between different sinks

79
Q

What are some of the main causes for flux changes?

A

Some of the main causes for flux change include climate conditions, natural events and human activity

80
Q

Climate conditions

When will rates of photosynthesis be higher?

A

Rates of photosynthesis will likely by higher in summer seasons, as there is more direct sunlight and longer days

81
Q

cc

how do oceanic temepratures affect co2?

A

Oceanic temperatures also determine how much carbon is stored as dissolved CO2 or as hydrogen bicarbonate ions

82
Q

cc

how do climate events change carbon flux?

A

Climate events like El Nino and La Nina will change the rate of carbon flux between ocean and atmosphere

83
Q

cc

how does the melting of polar ice caps affect carbon fluxes?

A

Melting of polar ice caps will result in the decomposition of frozen detritus

84
Q

what two natural events can affect co2 concentrations?

A

forest fires

volcanic eruptions

85
Q

How do forest fires affect co2 conc?

A

Forest fires can release high levels of carbon dioxide when plants burn (loss of trees also reduces photosynthetic carbon uptake)

86
Q

How do volcanic eruptions affect carbon dioxide concentration?

A

Volcanic eruptions can release carbon compounds from the Earth’s crust into the atmosphere

87
Q

What 3 human activities affect carbon dioxide concentration?

A

clearing of trees
ruminant livestock
fossil fuels

88
Q

How does clearing of trees affect co2 conc?

A

Clearing of trees for agricultural purposes (deforestation) will reduce the removal of atmospheric CO2 via photosynthesis

89
Q

How does increased number of ruminant livestock affect co2 conc?

A

Increased numbers of ruminant livestock (e.g. cows) will produce higher levels of methane

90
Q

Who has measured atmospheric co2 concs and where?

A

Atmospheric CO2 concentrations have been measured at the Mauna Loa Observatory (in Hawaii) since 1958 by Charles Keeling

91
Q

(findings from Charles Keeling)

how often do co2 levels flc=uctuate?

A

CO2 levels fluctuate annually (lower in the summer months when long days and more light increase photosynthetic rates)

92
Q

(findings from Charles Keeling)

WHat will global co2 patterns conform to and why?

A

Global CO2 trends will conform to northern hemisphere patterns as it contains more of the planet’s land mass (i.e. more trees)

93
Q

(findings from Charles Keeling)

How are CO2 levels changing?

A

CO2 levels are steadily increasing year on year since the industrial revolution (due to increased burning of fossil fuels)

94
Q

(findings from Charles Keeling)

How are CO2 levels now?

A

Atmospheric CO2 levels are currently at the highest levels recorded since measurements began

95
Q

Why may different monitoring stations have different trends in CO2?

A

Different monitoring stations may have slightly different trends due to seasonal variations and the distribution of local vegetation

IB Biology (38 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions