The Carbon Cycle

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What is the CARBON CYCLE?

the cycling of carbon between its different stores (ocean, land, lithosphere, atmosphere)

- carbon is one of the most chemically versatile elements

- present in all life forms

- can be found organically (biomass) or inorganically (fossil fuels)

carbon compounds can be very important

- carbon dioxide (keeps the earth warm)

- methane (greenhouse gas)

- limestone

- hydrocarbons (fossil fuels)

- molecules (DNA)

What are the ORIGINS of carbon on Earth?

- interior of the Earth (from within the mantle - semi-molten layer)

- plate boundaries (from mantle. Moves up through due to volcanic eruptions)

- stores such as biomass and oeans

- carbon removal (atmosphere/photosynthesis/when locked up in sedimentary rocks)

Carbon Stores

LITHOSPHERE

- crust and upper mantle

- inorganic form (fossil fuels and limestone)

- also organic form in humic substances (decaying matter)

stores...

- peat

- fossil fuels

- soil

- marine sediments (sedimentary rocks)

HYDROSPHERE

- oceans - dissolved carbon dioxide

- organisms like fish and plankton and some plants

stores...

- surface level

- intermediate layer

- living organic matter

BIOSPHERE

living part

- animals

- peat

- living vegetation

- soil humus

- plant litter

ATMOSPHERE

- carbon dioxide as a gas (control's Earth's temperature)

- atmospheric carbon dioxide is increasing (Mauna Loa Curve)

- caused by human activities releasing carbon dioxide into the atmosphere

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How does carbon MOVE BETWEEN STORES?

- human processes

- geological components

- photosynthesis

- decomposition

- oceanic carbon pumps

- combustion

- volcanic activity

What is a CARBON SINK?

store that takes in more carbon than it releases

What is a CARBON STORE?

releases more carbon than it takes in

Geological components

The rock cycle

- volcanic activity

- subduction at plate boundaries

- burial

- weathering

- formation of limestone due to the formation of carbonic acid

- sedimentary rock that contains limestone. Through plate subduction, the limestone is melted and released through volcanic activity and the carbon dioxide is released into the atmosphere.

Photosynthesis

- formation of glucose by plants

- uses carbon dioxide

Respiration

- releases energy from glucose

- also produces carbon dioxide

Decomposition

- recycles carbon into soil by deceomposers

Oceanic Carbon Pumps

- to do with oceanic circulation of warmer or colder currents (deeper)

- cools when in contact with ice and sinks (denser)

- transfers carbon dioxide from warmer currents to colder currents

Combustion

- releases carbon dioxide from organic material when burnt

Volcanic eruptions

- CO2 is stored in the mantle

Human Activity

- extraction of hydrocarbons

- farming practices

- deforestation

- consumption of fossil fuels

- urban growth

Carbon Sequestration

- carbon dioxide is captured from the atmosphere and held in long term storage

- helps prevent global warming

- geological sequestration (within rocks)

- terrestial (within trees and plants)

What are the effects of the CHANGING CARBON BUDGET?

(GLOBAL WARMING)

- effects on land are unclear as it hasn't been studied for long enough

Oceans

- sea level rise

- melting sea ice

- acidification (removes carbonate ions - less alkaline - coral bleaching)

- salinity is reduced

- cloudy water - increase in phytoplankton - less sunlight reaching plants