Copepod migrations are important for the ocean’s CO2 uptake


Calanus finmarchicus is one of the most abundant copepod species in the North Atlantic and is an extremely important source of food for many commercial fish species such as cod larvae, herring and capelin. Credit: Sigrun Jonasdottir, DTUAqua

Copepod migrations are important for the ocean’s CO2 uptake

Posted: 08 Sep 2015 06:41 AM PDT

Zooplankton no bigger than grains of rice play a much larger role in the transport and storage of CO2 in the ocean than previously thought, scientists report.
In a scientific article recently published in Proceedings of the Academy of Sciences (PNAS), researchers from DTU Aqua, the University of Copenhagen and the University of Strathclyde, Scotland, have shown that the ocean’s tiny copepods actively transport carbon down to the deep water in the North Atlantic during their winter hibernation. The discovery means that our understanding of the planet’s carbon cycle, and the ocean’s ability to absorb carbon needs to be revised. Changes in the carbon cycle are the cause of climate change. “The active transportation of carbon from the atmosphere into the ocean has never been quantified at this scale before, but our calculations indicate that we may be able to double the previous estimate for the North Atlantic carbon capture,” said DTU Aqua’s Senior Researcher Sigrun Jonasdottir, the lead contributor to the article…”Once again we can see here a fantastic example of how important biology — and biological diversity — is for the chemical and physical processes on Earth. The ocean’s carbon cycle is a vital component of climate models. At the moment, only passive biological processes are calculated into these models, for example when dead material sinks down through the water. But our study shows that we also have to include the active biological processes, such as animal migrations, to predict and calculate the ocean’s ability to absorb anthropogenic emissions of CO2,” says Professor Katherine Richardson of the University of Copenhagen, who is also one of the authors behind the study.

Copepods are themselves threatened by climate change

This does not mean, however, that we can just rely on water copepods to soak up the increased human-made emissions of greenhouse gases by dragging additional carbon down into the depths of the ocean. On the contrary, a warmer sea can lead to a reduction in the specie’s ability to go into hibernation and thus lessen the effect, according to Sigrun Jonasdottir from DTU Aqua. “This process has been going on for thousands of years, so it’s not a new mechanism by any means. But changes in the ocean, such as the water getting warmer and ocean currents changing, may have consequences for the copepods and their biology. Therefore, we might be running the risk that climate change will weaken the process and as a result reduce the ocean’s ability to absorb CO2.”….


  1. Sigrún Huld Jónasdóttir, André W. Visser, Katherine Richardson, Michael R. Heath. Seasonal copepod lipid pump promotes carbon sequestration in the deep North Atlantic. Proceedings of the National Academy of Sciences, 2015; 201512110 DOI: 10.1073/pnas.1512110112

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