What is it about?

Half of global primary production takes place in the ocean. The marine primary producers, algae, sink after they die and bring with them carbon. Some of this carbon, that originates from CO2 in the atmosphere, is transported to the deep ocean where it is stored for the foreseeable future. This is called the biological carbon pump and it is important to understand this process as carbon sink. While sinking, organic carbon is respired forming CO2 again, and how much carbon is transported to the deep ocean depends both on sinking speed and respiration while sinking. Here we try to understand the respiration of the sinking carbon in relation to its sinking speed, which is used to estimate how much of the sinking carbon is reaching deep enough to be stored.

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Why is it important?

Models of the biological carbon pump have sinking speed and respiration as independent variables. Here we demonstrate that they are connected and speculate that this is due to the porosity of particles affecting both speed and respiration. This is important to take into consideration to produce better models of the biological carbon pump.


Our results stem from freshly derived organic carbon, and this relationship is likely not the same deeper down when much of the easily degraded carbon have been consumed. This would require further studies to better understand the whole process.

Kristian Spilling
Finnish Environment Institute

Read the Original

This page is a summary of: Respiration rate scales inversely with sinking speed of settling marine aggregates, PLoS ONE, March 2023, PLOS,
DOI: 10.1371/journal.pone.0282294.
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