Carbon Cycle

Carbon Compound - Bio-Molecules

Produced in living things. e.g. fats, oils, DNA

Carbon Compound - Carbon Dioxide (CO₂)

A gas found in the atmosphere, soils, and oceans. (Implications for climate change)

Carbon Compound - Methane (CH₄)

A gas found in the atmosphere, soils, oceans, and sedimentary rock.

Carbon Compound - Calcium Carbonate (CaCO₃)

Solid compound found in rocks, oceans, and skeletons.

Carbon Compound - Hydrocarbons

Solids, liquids, or gases found in sedimentary rock.

Carbon Store - Marine Sediment and Sedimentary Rock

Stores 100,000bn metric tonnes of carbon.

By far the largest store of carbon, it is a long term store with rocks taking millions of years to form.

Carbon Store - Ocean

Stores 38,000bn metric tonnes of carbon.

A very important carbon store, as CO₂ is directly absorbed and stored in solution. Absorbed more from the atmosphere since the industrial revolution.

Carbon Store - Fossil Fuel Deposits

Stores 4,000bn metric tonnes of carbon.

Hydrocarbons are important long term stores, but have been exploited for heat & power, increasing atmospheric CO₂.

Carbon Store - Soil Organic Matter

Stores 1,500bn metric tonnes of carbon.

Soil contains rotting organic matter which are important stores. Increased release due to deforestation.

Carbon Store - Atmosphere

Stores 750bn metric tonnes of carbon.

Carbon held in the atmosphere in CO₂, increased due to power stations, vehicles, & deforestation.

Carbon Store - Terrestrial Plants

Stores 560bn metric tonnes of carbon.

Plants are vital for all life on earth, storing carbon for years and transfer into the soil.

Carbon Stores

The main stores of carbon are the lithosphere, hydrosphere, cryosphere, atmosphere, and biosphere.

Carbon Sink

A store that absorbs more carbon than it releases.

Carbon Source

A store that releases more carbon than it absorbs.

Carbon Transfer

Processes that transfer carbon between the stores. Inputs and outputs affect the size of the carbon stores. e.g. Photosynthesis.

GTC

A Gigatonne of CO₂ is used to measure the amount of Carbon in stores.

1GTC = 1bn metric tonnes.

Transfer of Carbon within the cycle measured in Gigatonnes per year (GTC/yr)

Anthropogenic CO₂

Carbon Dioxide generated by human activity.

Carbon Sequestration

The capture of CO₂ from the atmosphere or capturing anthropogenic from a large scale stationary sources like power plants before its released into the atmosphere.

Once captured it can be put into long term storage.

Greenhouse Gas

Any gaseous compound in the atmosphere that is capable of absorbing infrared radiation, thereby trapping and retaining heat in the atmosphere.

Cascading System

Outputs of one system are inputs to another system.

e.g. Oceans and Phytoplankton

Movement of Carbon - Photosynthesis

Through the process, Carbon Dioxide is converted into glucose and produces Oxygen into the atmosphere.

Movement of Carbon - Respiration

All cells, plants, and animals respire: breath in air, absorb what is necessary, exhale what isn’t (usually CO₂).

Movement of Carbon - Decompostion

When organisms die they are consumed by decomposers, Carbon from their bodies returns to the atmosphere as CO₂.

Movement of Carbon - Combustion

When organic material is burned with oxygen, it is converted into energy, CO₂, + water which is then returned to the atmosphere.

Movement of Carbon - Burial and Compaction

When organic matter is buried and compacted, it may form hydrocarbons in fossil fuels, or limestone. Hydrocarbons will release CO₂ into the atmosphere if burned, whilst limestone will hold carbon for millions of years.

Movement of Carbon - Weathering

Carbon is held in solution when rocks dissolve, then moved into the water cycle where it is used to build marine shells.

Movement of Carbon - Sequestration

Geological: Carbon capture and storage.

Terrestrial/Biological: Stored in the stems/roots as well as soil.

Carbon: Transfer of carbon from atmosphere to plants, soil, rocks, and oceans.S

Slow organic carbon cycle

Takes millions of years and involves the long term sequestration as fossil deposits in oil, coal, and gas.

Slow non-organic carbon cycle

Involves the transfer of carbon from the atmosphere to hydrosphere & to sedimentary stores recycled through tectonics back into the atmosphere.

Fast organic carbon cycle

Operates in months to centuries mainly involving the transfer of organic carbon between the atmosphere, soil, and biosphere.

Fast non-organic carbon cycle

Involves the ocean and atmosphere exchanging CO₂ depending on the relative conditions of both.

Lithosphere

The crust and uppermost mantle, the hard and rigid outer layer of the earth.

Inorganic storage - fossil fuels & carbonate-based sedimentary deposits. (e.g. limestone)

Organic storage - litter, organic matter, substances found in soils.

Fossil Fuels - 4,100GTC

Peat - 250GTC

Hydrosphere

The total amount of water on the Earth.

Variations estimate 37,000-40,000GTC stored in the hydrosphere.

• Surface layer (Euphotic Zone) - Photosynthesis (900GTC)

• Intermediate/Disphotic (Twilight Zone) - Deep layer (37,100GTC)

  • Living Organic Matter/Aphotic - Fish, Plankton, Bacteria (700GTC)

Biosphere

Total sum of all living matter.

Terrestrial Biosphere - 3,170GTC

Distribution of Carbon depends on the ecosystems.

30% of Globes Carbon is stored in Peat.

Atmosphere

The layer of gases that surrounds the earths surface.

Stores 720-800GTC. (0.04%)

The CO₂ is its highest in 800,000 years, possibly even 20 million years.

Its vital to regulate earths temperature, but global warming has increased industrial CO₂.

Mauna Loa Observatory, Hawaii has used the Keeling Curve to measure atmospheric carbon since 1958.

Sere

A vegetation succession relating to a specific environment.

Seral Stage

Lithosere - vegetation occurs on bare rock

Hydrosere - vegetation occurs in water & ponds

Halosere - vegetation occurs in saltmarshes

Psammosere - vegetation occurs on coastal/sand dunes

Physical changes to the carbon cycle - Wildfires

1997-98 and 2003, Indonesia wildfires burnt out of control for months.

Physical changes to the carbon cycle - Volcanic Activity

Returns 130-180 million tonnes of carbon that has been trapped in the Lithosphere for millions of years.

Humans release 30bn tonnes by burning Fossil Fuels.

Physical changes to the carbon cycle - Milankovitch Cycles

There is a delay between temperature change and CO₂

Some scientists believe that these long term trends are because of changes in the orbital cycle.

Physical changes to the carbon cycle - Milankovitch Cycles: Eccentricity

Change in the shape of the earths orbit around the sun. (100,000yrs)

Elliptical = Difference in solar radiation increases, leading to greater seasonal contrasts.

Circular = Seasonal variation in solar energy is smaller.

Physical changes to the carbon cycle - Milankovitch Cycles: Obliquity

Change in the tilt of earths axis between 22.1^o and 24.5^o. (41,000yrs)

A greater tilt means more extreme seasons, smaller = milder seasons.

A smaller tilt favours glacial periods because of cooler summers = less ice melting.

Physical changes to the carbon cycle - Milankovitch Cycles: Precession

When the axis of the earth wobbles. (23,000yrs)

Changes the timing of the seasons in relation to the earths position around the sun.

Affects the contrast between seasons, especially between hemispheres.

Enhanced greenhouse effect

The impact on the climate from the additional heat retained due to increased amounts of CO₂ and other greenhouse gasses that humans have released into the atmosphere since the industrial revolution.

Geo-sequestration

Technology capturing greenhouse gas emissions from power stations and pumping them into underground reservoirs.

Radiative Forcing

The difference between in coming solar energy absorbed by the earth and energy radiated back to space.

Soil Organic Carbon (SOC)

Organic constitutes in the soil; tissues from dead plants and animals, products produced as these decompose and the soil microbial biomass.

Thermal Expansion

When water heats up, it expands. ½ of the past century’s sea level rise is attributable to warmer oceans simply occupying more space.

Human changes to the carbon cycle - Fossil Fuel combustion

Fossil fuels are roughly 11-70 million years old, and release carbon when burned as they are made up mostly of Carbon and Hydrogen.

The cement industry produces 5% of all human induced CO₂, 50% of Calcium Carbonate heating, and 40% burning fuel to power the process.

• Every 100kg of cement produced, releases 900kg of CO₂

In 2013: Global CO₂ emissions was 36 GTC, dominated by China, USA, and India. Coal, oil, and gas were the top emitters.

Human changes to the carbon cycle - Farming Practices

When the soil is ploughed, its layers invert allowing air to mix in, this increases soil microbial activity resulting in more productive soil.

In 2011: Enteric Fermentation was 39% of all agricultural carbon emissions.

Asia is the continent which emits the most carbon from agriculture.

Human changes to the carbon cycle - Land Use Change

CO₂ emissions from land use change account for 30% of all human-induced carbon emissions.

Deforestation accelerates the release of carbon from ground biomass as well as trees, especially from slash and burn techniques.

Human changes to the carbon cycle - Carbon Sequestration

Geological - injected as liquid deep underground into depleted oil and gas reservoirs, or deep in the ocean.

Terrestrial/Biological - Plants capture CO₂ which is stored in stems and roots along with the soil, enriching ecosystems, and associated wildlife habitats. But the carbon is never permanently removed from the atmosphere.

Carbon Budget

The amount of carbon stored and transferred within the carbon cycle on a global and local scale.

El Nino

Weaker trade winds and upwelling causes a change in the warm and cold water levels.

Causes drought in Australia, and flooding in South America.

La Nina

Strong trade winds blow warm water at the ocean’s surface from South America to Oceania and Asia, increasing upwelling near South America.

Causes flooding in Australia, and droughts in South America.