Topic 4b - Carbon and phytoplankton

Carbon is a fundamental building block of life. As such carbon is a common component in most ecosystem and climate models.

To know if these models are correct, and to understand what drives the carbon cycle, we need data to help us understand ocean carbon content. Satellite ocean colour data offer suitable spatial and temporal scales to capture this by measuring reflected light. The challenge is to understand what links carbon with variability in the ocean colour signal. This can be tricky.

Burning any carbon-based fuel releases carbon dioxide into the atmosphere, a main contributor to the current climate change we are experiencing. The biological pump pulls carbon dioxide down in to the ocean, through the actions of phytoplankton, such as photosynthesis. We can get estimates of phytoplankton production from ocean colour derived chlorophyll a concentrations. However, the ratio of carbon to chlorophyll varies depending on the size of the phytoplankton cells, the species present and their physiological variability.

There are also other types of carbon in the oceans, from different sources. Near the coast, rivers will contribute sediments and dissolved matter, containing carbon. These will vary according to different factors to those which influence phytoplankton, so separating the ocean colour signal to quantify these different pools is important for understanding the overall dynamics of the ocean carbon cycle.

Featured Educators:

  • Dr Victor Martinez-Vicente

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EUMETSAT Oceans MOOC Data Viewer

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Don’t forget you can download the video and transcript with the links on the right.

Optional Further Reading


Poco map
Carbon and Chlorophyll map
Carbon diagram
Biological Carbon Pump

Schematic explaining the concept of the biological carbon pump – how phytoplankton contribute to take-up and storage of atmospheric carbon dioxide.