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. Web resource: http://www.msrc.sunysb.edu/octet/biological_pump.html

The Biological Pump This slideshow will take you through the steps of the biological pump.

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

CO2 Photosynthesis Phytoplankton

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

CO2 Photosynthesis Respiration Phytoplankton

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

CO2 Photosynthesis Respiration Phytoplankton Zooplankton Consumption

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.

CO2 Phytoplankton Zooplankton Bacteria Photosynthesis Respiration Consumption Decomposition Bacteria

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

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

Higher Trophic Levels The process continues…

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

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

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

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