Carbon sequestration in the oceans

Question 1

What two mechanisms are used by the oceans to take up carbon

Answer 1

Physical pump

Biological pump

Question 2

What is the physical (inorganic) pump

Answer 2

Mix of surface and deep ocean water by vertical currents
Creating a more even distribution of carbon - vertically and geographically
Carbon enters ocean from atm via diffusion
surface ocean currents transport water and dissolved CO2 towards the poles
This cools and sinks (downwelling)

Question 3

What is downwelling

Answer 3

When water cools and becomes more dense then sinks

Question 4

Effect of downwelling on carbon cycle

Answer 4

Carries dissolved carbon to the ocean depths where individual carbon molecules may remain for centuries

Question 5

What is upwelling

Answer 5

Eventually deep ocean currents transport the carbon to areas of upwelling
Carbon-rich water rises to the surface and CO2 diffuses back into the atm

Question 6

What is the biological (organic) pump

Answer 6

Carbon is also exchanged between the oceans and the atmosphere through the action of marine life
Nearly half of all carbon fixation by photosynthesis takes place in the oceans
50 GT of carbon is drawn down from the atmosphere each year

Question 7

Marine organisms importance

Answer 7

Drive the biological pump

Phytoplankton photosynthesise which removes dissolved carbon form the ocean

Question 8

What is the fate of marine organisms

Answer 8

Phytoplankton are either consumed by zooplankton and passed along the food chain/ die and decompose which releases the stored carbon/die and sink to the ocean floor