Fast and slow

Question 1

Photosynthesis (fast)

Answer 1

the absorption of CO2 from the atmosphere (terrestrial plants) and from oceans (marine plants) to produce organic carbon structures.

Question 2

Respiration (fast)

Answer 2

the release of CO2 into the atmosphere, soil and oceans by animals as they exhale.

Question 3

Digestion (fast)

Answer 3

the release of carbon compounds by terrestrial and marine animals after feeding on carbon-rich material.

Question 4

Decomposition (fast)

Answer 4

the breakdown of animals and plant structures by bacteria and the release of carbon compounds into the atmosphere, soil and to the ocean floor. Where oxygen is present it releases CO2, where it is absent CH4 is released.

Question 5

Combustion (fast)

Answer 5

natural fires release carbon compounds from vegetation to the atmosphere

All these involve living (organic) processes in some way.

Additionally, there is an on-going transfer of CO2 that is non-organic:

Question 6

Ocean-atmosphere exchange (fast)

Answer 6

there is a mutual transfer of CO2 between the lower atmosphere and ocean surfaces. The flow can go in either direction depending on the balance of CO2 between the two stores, temperature and conditions of air and water, but the prevailing direction is from the atmosphere to the ocean.

Question 7

The transfer of carbon into the oceans from the atmosphere and land surface (slow)

Answer 7

Direct CO2 absorption as part of the atmosphere-ocean exchange is supplemented by the erosion of carbon-rich terrestrial surfaces as naturally-acidic rainfall dissolves surface rocks and transfers soluble bicarbonate compounds, via rivers, to the sea.

Question 8

The deposition of carbon compounds on the ocean floor (slow)

Answer 8

Marine plants (including phytoplankton) absorb CO2 and marine creatures take in carbon to construct skeletons and shells. Phytoplankton are consumed by zooplankton and their carbon-rich excrement falls to the ocean floor. The skeletal and shell remains of marine creatures also fall the sea bed.

Question 9

The conversion of ocean sediments into carbon-rich rock (slow)

Answer 9

On continental shelves carbon-rich accumulations of deposits may be converted into carbon-rich rocks (such as chalk and limestone) or become contained as concentrations within sandstones and shales to form organic deposits, some of which become fossil-fuel reserves in time. This process of sedimentary rock formation is called lithification.

Question 10

The transfer of carbon rocks to tectonic margins (slow)

Answer 10

As sedimentary rocks are created by heat and pressure over millions of years, they are also moved in the direction their crustal plate is moving. If they eventually become a collision margin, they may be uplifted to become surface mountain ranges (as in the Himalayas). The carbon-rich strata may then be exposed to weathering and erosion to return to the ocean as eroded carbonate rocks.

Question 11

The return of carbon compounds to the atmosphere in volcanic eruptions (slow)

Answer 11

At subduction zones, carbon-rich rocks may be ejected at the surface from volcanic eruptions, usually in the form of gaseous compounds into the atmosphere. Here, CO2 contributes to the formation of carbonic acid in clouds, which then begins the process of solution of surface rocks and a starting of the terrestrial component again, or being absorbed by ocean surfaces for the marine component.