The zooplankton group, known as copepods, build up carbon-rich lipids as a nutritional reserve during late summer whilst they are in the surface waters of the ocean. Then, they use these reserves to survive their winter hibernation period which they spend at around one mile down in the deep ocean, out of contact with the atmosphere.
This means that the CO2 released by the hibernating copepods as they use up their lipid reserves does not find its way back into the atmosphere but is instead stored in the depths, where it can remain for thousands of years. The team which undertook the research have called this process the ‘copepod lipid pump’.
The research showed that one copepod species alone, Calanus finmarchicus, carries between one million and three million tonnes of CO2 from the atmosphere into the depths of the North Atlantic Ocean each year.
Professor Michael Heath, of Strathclyde’s Department of Mathematics & Statistics, was a partner in the research. He said: “The deep over-wintering of these copepods has been known about for a while but this is the first time that their role in carbon storage has been measured. The results could double the estimates of how much carbon dioxide is being absorbed by the North Atlantic Ocean.
“The role of CO2 in climate change and the urgent need for action to reduce emissions is increasingly well understood. What is particularly important about our results is that the role of the lipid pump, is not taken into account in the existing climate models used by the IPCC. We need to look into this further to find out whether the same thing is happening in other oceans of the world, and how it can be included in the next generation of IPCC models.
“These copepod migrations don’t provide a solution to the emissions problem, but our results are certainly part of the process of building up a better understanding of how the planet is responding to increasing CO2 levels”.
The research has been published in the journal Proceedings of the Academy of Sciences. It was led at the Technical University of Denmark (DTU) and also involved the University of Copenhagen.
The research was financially supported by the Danish Strategic Research Council (NAACOS), the EU’s 7th framework programme (EURO-BASIN), and the Marine Alliance for Science and Technology Scotland (MASTS). Professor Heath’s post at the University of Strathclyde is also funded by MASTS.
Proceedings of the Academy of Sciences: ‘Seasonal copepod lipid pump promotes carbon sequestration in the deep North Atlantic‘