1.A.6 The Carbon cycle

Inputs to the carbon cycle

Energy from the sun

Outputs of the carbon cycle

Co2, combustion of fossil fuels, plant , root and animal respiration, photosynthesis, dead plant material

Stores in the carbon cycle

Ocean water and marine organisms

Ocean floor sediments

Vegetation

Animals/ consumers

Fossils + fossil fuels

Transfers in the carbon cycle

Decomposition

Organic carbon

Burial

Net Carbon Sink

The carbon entering the store is greater than the carbon leaving the store

Net Carbon source

The carbon leaving the store is greater than the carbon entering the store

Lithosphere stores of carbon

6000 GtC stored in fossil fuels, soil matter and peat. Most of this carbon is stored in marine sediments

Carbon in the hydrosphere

40,000 GtC in the hydrosphere, stored in dissolved carbon, organisms, and dissolved organic matter

Carbon in the cryosphere

0.01% of the worlds carbon, mostly frozen organic material although snowflakes trap CO2 in their air gaps.

Carbon stored in the biosphere

3100 GtC stored here. Animals hold little carbon as they are transfers not stores. Forests hold ½ of this, with peat, leaf litter and soil holding the rest

Atmosphere as a store of carbon

720-800 GtC stored today in the atmosphere. Human emissions have made this store higher than in the past 20 million years. It is measured from hawaai becuase there is no interference

Continental Scale

Where a process is happening at a very large geographical scale

Sere scale

Where processes happen for a single biome or ecosystem

Photosynthesis

Using energy from the sun to combine CO2 and H2O to form carbohydrates (CH2O)

Factors affecting photosynthesis

The amount of vegetation

The type of vegetation ( grass photosynthesises less than trees)

Climate

Amount of atmospheric CO2 ( CO2 is needed for carbs so the more CO2 the more photosynthesis

Reepiration

Animals ( + photosynthesising algae & bacteria) using some of the stored carbohydrates as energy to carry out life functions

Factors affecting respiration

Amount of animals

Rate of increase in the number of animals

Climate

Amount of food available

Human activity (agriculture and number of livestock)

Decomposition

Rotting/ decaying of matter transferring carbon from organic matter into the ground/lithosphere

What factors affect decomposition?

Amount of dead organic matter produced

Presence of decomposers ( bacteria, fungi etc)

Presence of air and water, controlled by weather and seasons

Type of ecosystem, no decomposition in hot deserts

Combustion

The burning of organic material in the presence of oxygen

Factors affecting combustion

Amount of dry vegetation

Temperature and PPT

Fossil fuel reserves

Human activity (rate of extraction and consumption of fossil fuels)

Burial

A geological timescale process where the lithosphere is subducted at destructive plate margins

Carbon sequestration

The human process of capturing CO2 from the atmosphere and putting it into long term storage

Geological sequestration

CO2 is captured at source then injected in liquid form into underground stores( oil and gas reserves)

Terrestrial/ biological sequestration

Use of plants/ trees to long term store CO2. The carbon is stored in plant matter for hundreds/thousands of years, instead of being in the atmosphere