the carbon cycle

where is inorganic carbon found

in rocks as bicarbonates and carbonates

where is organic carbon found

in plant material and living organisms

where is gaseous carbon found

found as CO2 and CH4 (methane)

define equilibrium within the carbon cycle

a balance between the production and absorption of carbon (or sources and sinks).

what is dynamic equilibrium within the carbon cycle

although the amounts of carbon are constantly changing in different stores, the overall rates of inputs and outputs remain balanced

give an example of when it could take a long time for equilibrium to be reached

after a volcanic eruption

define a carbon sink

any store of carbon that takes in more carbon that it emits

describe photosynthesis

• living organisms convert carbon dioxide form the atmosphere and water from the soil into oxygen and glucose by using light energy

• by removing carbon dioxide from the atmosphere, plants are sequestering carbon and reducing the potential impacts of climate change

give an in-depth definition of where photosynthesis takes place in a plant  

in the chlorophyll of the leaves of a plant, to create the carbohydrate glucose.

what is the name of the chemically opposite process of photosynthesis

respiration

how does night and day affect photosynthesis and respiration of plants

• during the day, they photosynthesis more so they intake a lot more carbon than they emit via respiration

• during the night, rate of respiration if greater than photosynthesis

• however overall, plants absorb a lot more CO2 than they emit, so they are net carbon dioxide absorbers.

describe the process of combustion

organic matter such as trees are burnt, which emits CO2 into the atmosphere that was previously locked inside them.

it can also occur when fossil fuels are burnt to produce energy, or during wildfires

describe the transfer of carbon during decomposition

• when living organisms die, they are broken down by decomposers e.g. bacteria and detritivores

• these decomposers respire, returning CO2 to the atmosphere.

• some organic matter is returned to the soil and stored, which contains organic carbon.

describe the transfer of oxygen during diffusion

• oceans absorb CO2 from the atmosphere, which increases ocean acidity.

how is increased ocean acidity harming aquatic life

acidic seawater causes coral bleaching- many of the world’s coral reefs are now under threat

what is the biggest carbon store

the ocean

how much has ocean acidity increased since pre-industrial times

by 30%

what happens during carbonation weathering

• CO2 in the air mixes with rainwater

• this creates carbonic acid which aids erosion of rocks such as limestone

where does the carbonic acid from carbonation go

• it is moved through the water cycle and enters the oceans

• marine organisms use the carbon in the water to build their shells

describe burial and compaction 

• when shelled marine organisms die, their shells fall to the ocean floor and become compacted over time to form limestone

• organic matter from vegetation and decaying marine organisms is compacted overtime, whether ion land or in the sea, to form fossil fuel deposits.

give an example of carbon sqeuqatration

• a plant sequesters carbon when it photosynthesises

• Carbon Capture and Storage (CCS) is when CO2 is captured and transported via pipelines to depleted gas fields and saline aquifers

give some advantages of carbon sequestration in the form of Carbon Capture and Storage (CCS)

• can be fitted to existing coal power stations

• captures 90% of CO2 produced

• there is a demand for CO2 (e.g. Coca Cola, Plant Growth, Beer) so transport systems via pipeline in liquid form already exist

• potential to capture half of the worlds CO2 emissions

give some disadvantages of carbon sequestration in the form of Carbon Capture and Storage (CCS)

• high cost is the main restriction to the growth of CCS

• increases energy demand of power stations

• may not be space to fit it to existing power stations

where does the carbon cycle occur on a local scale

in a plant or in a sere

what is a sere

a stage of a vegetation succession and can relate to specific environments

when does a vegetation succession occur

when a plant community develops and becomes more complex over time

what is the climax of a sere 

the final stage of the sere when environmental equilibrium is reached and the ecosystem is fully developed and stable

give an example of a climax community

woodland, rainforest

what is the lithosere

bare rock

what is the halosere

salty environment

what is the hydrosere

freshwater environment

what is the psammosere

sand coastal environment

how much carbon has been emitted from coal in Gt

673 Gt

how much carbon has been emitted from oil in Gt

496 Gt

what is the biggest emitter of carbon since 1750

oil (at 673 Gt)

what is the main carbon store

• marine sediments and sedimentary rocks- lithosphere

• 66,000 - 100,000 million billion metric tonnes of carbon

how much carbon does the lithosphere store

66,000 - 100,000 million billion metric tonnes of carbon

what is the second largest store of carbon

• oceans- hydrosphere

• 38,000 billion metric tonnes of carbon

how much carbon does the oceans store

36,000 billion metric tonnes of carbon

how much carbon do fossil fuel deposits store in the lithosphere 

4000 billion metric tonnes of carbon

what store of carbon is currently changing in terms of its location worldwide

trees- due to deforestation.

• forests are currently declining in tropical areas in the southern hemisphere, and growing in the northern hemisphere

what are the eight countries with the largest forested areas

• brazil

• russia

• chine

• canada

• USA

• DRC

• australia

• indonesia

how has the rate of forest loss changed from the 1990’s to 2010-2015

is has decreased from 9.5 million hectares peer year to 5.5 million hectares per year

discuss whether wildfires are good or bad

• transfer carbon from biosphere to the atmosphere

• burning can encourage the growth of plants in the long term

• can destroy homes

discuss volcanic activity (case study Tambora Indonesia)

• carbon stored within the earth is released mainly as CO2 into the atmosphere

• the 1815 Mt Tamobora eruption in Indonesia produced sulphur dioxide gas, which then entered the atmosphere, blocking radiation from the sun and reducing global temperatures by 0.4 - 0.7 *C in 1816.

• this reduced photosynthesis rates, which also affects the water cycle

what is the main technique for deforestation

‘slash and burn’ which interrupts the forests carbon cycle to clear land for farming/ housing

how do farming practices affect the carbon cycle

• pastoral farming releases CO2 as animals respire

• ploughing releases CO2 stored in the soil

• farm machinery such as tractors may release CO2

what is a flux

changes to the magnitude of carbon stores over time. These may happen very rapidly or over thousands of years.

define the carbon budget

the balance between carbon inputs and outputs to a store OR the balance of exchanges between the four major stores of carbon

define a carbon source and give an example

a store that emits more carbon than it absorbs e.g. a damaged rainforest

define a carbon sink and give an example

a store that absorbs more carbon than it emits e.g. an untouched rainforest

what is the enhanced greenhouse effect 

• high levels of greenhouse gases are being produced by humans

• this traps radiation from the sun, leading to global warming and climate change 

how do increasing temperatures due to changes in the carbon cycle affect the water cycle

• greater levels of evapotranspiration

• summer storms more likely

• decrease rainfall in summer on average

• increase average winter rainfall

in the Amazon, what percentage of deforestation is for cattle ranching

70%

what crop has high methane emissions, and what are the alternatives

rice pads fields have high methane emissions due to increased productivity from higher CO2 levels. More sustainable grans like quinoa are being considered because they require less water to grow.

discuss how urbanisation affects the carbon cycle 

• affects local and global carbon cycles

• vegetation is replaced by concrete and soils are covered

• urban areas occupy 2% of the worlds land mass, but these areas account for 97% of all human caused global CO2 emissions.

what is the data for and what is the milankovitch Cycle

• Vostok ice core data from Antarctica suggest that the past temperature change has occurred before carbon dioxide levels have risen.

• it is possible that variations in the earth’s orbit cause periods of time where we experience greater heating effect from the sun, increasing global temperatures

how can increasing temperatures affect the carbon in the hydrosphere

• this increase in temperatures causes glaciers to melt and therefore increases flows in the carbon cycle (because increases decomposition of organic matter in warming rivers); allowing more Co2 to enter the atmosphere and for global temperatures to rise further

• this is an example of positive feedback

• the quantity of freshwater flowing into the oceans increases.

• as the oceans become warmer, they release more CO2 into the atmosphere (colder water can store more CO2), causing further global temperature rises.

during what periods is it thought to be natural for CO2 levels to increase

during interglacial periods there is a natural CO2 and temperature increase

asides from possible theories, what percentage of climate scientists believe that global warming over the last 100 years is due to human activity

97%

do warmer oceans store more of less CO2

less

define negative feedback

the process that occurs is counteracted by an opposing process, causing the effects to cancel each other out and nothing to change

define positive feedback

a process occurs, which causes another process to occur, which starts a chain reaction that heightens the first process

explain how a wildfire acts as a positive feedback system

wildfires are more likely in hotter and drier climates created by global warming, which release large quantities of co2 into the atmosphere, which in turn then increases the warming effect

explain how the melting of permafrost is a positive feedback system

higher temperatures are thawing the permafrost, releasing Co2 and methane (which has 20 times the warming effect of co2) causing warming on a local and global scale

permafrost is frozen ground that remains at a temperature of 0&C or lower for at least 2 consecutive years

the higher temperatures cause more permafrost to melt, causing further gas release and warming.

explain how the Albedo effect is a positive feedback system

as the earth warms, ice and snow (which are highly reflective) melt, exposing darker rock underneath. These darker surfaces absorb more solar energy, which leads to further warming

explain how photosynthesis is a negative feedback loop

• increased photosynthesis by plants from rising temperatures allows vegetation to grow in new areas e.g. where permafrost has melted.

• new vegetation absorbs co2 from the atmosphere, decreasing the warming effect

explain how increasing cloud cover is an example of a negative feedback system 

• increased temperatures lead to an increase in evapotranspiration, leading to more cloud cover

• clouds reflect sunlight and radiation, resulting in a cooling effect 

what does anthropogenic mean

originating from human activity- human induced change