1. The Biological Pump
The biological pump is the process by which CO2 fixed in photosynthesis is transferred to the ocean interior resulting in a temporary or permanent sequestration (storage) of carbon.
This biogeochemical process involving phytoplankton, the animals that consume them, and the bacteria that assimilate their waste plays a central role in the global carbon cycle.
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2. The Biological Pump
This slideshow will take you through the steps of the biological pump.

3. Photosynthesis
Carbon dioxide is removed from the atmosphere by producers that use CO2, sunlight and nutrients to make food through the process of photosynthesis.

4. CO2
Photosynthesis
Phytoplankton

5. Respiration
Some CO2 is then released back into the water through respiration as the phytoplankton break down their food to release energy.

6. CO2
Photosynthesis
Respiration
Phytoplankton

7. Consumption
Some of the carbon is passed on to primary consumers: zooplankton and other filter feeders that depend on phytoplankton for their energy.

8. CO2
Photosynthesis
Respiration
Phytoplankton
Zooplankton
Consumption

9. Decomposition
Bacteria play a vital role in the biological pump by decomposing organic particles such as waste products and dead organisms that sink to the deep sea (Aerobic decomposition releases CO2). In the upper oceans, bacteria can actually weaken the biological pump by reducing particulate flow to the deep.

10. CO2 Phytoplankton Zooplankton Bacteria Photosynthesis Respiration
Consumption
Decomposition
Bacteria

11. Higher Trophic Levels
Consumption continues to transport carbon through higher trophic levels.

12. CO2 CO2 Phytoplankton Zooplankton Higher Level Consumers Bacteria
Photosynthesis
Respiration
Phytoplankton
Respiration
Zooplankton
Consumption
Higher Level Consumers
Decomposition
Consumption
Decomposition
Bacteria

13. Higher Trophic Levels
The process continues…

14. CO2 CO2 CO2 Phytoplankton Zooplankton Higher Level Consumers Bacteria
Photosynthesis
Respiration
Phytoplankton
Respiration
Zooplankton
Respiration
Consumption
Higher Level Consumers
Decomposition
Consumption
Decomposition
Bacteria

15. Remineralization
As bacteria break down organic matter, the CO2 that is not remineralized is stored in the deep-ocean sediments.

16. CO2 CO2 CO2 CO2 Phytoplankton Zooplankton Higher Level Consumers
Photosynthesis
Respiration
Phytoplankton
Respiration
Zooplankton
Respiration
Consumption
Higher Level Consumers
Decomposition
Consumption
Decomposition
Bacteria
Remineralization
CO2

17. CO2 CO2 CO2 CO2 Phytoplankton Zooplankton Higher Level Consumers
Photosynthesis
Respiration
Respiration
Respiration
Phytoplankton
Zooplankton
Decomposition
Consumption
Higher Level Consumers
Decomposition
Consumption
Bacteria
Remineralization
CO2