Seasonal copepod lipid pump promotes carbon sequestration in the deep North Atlantic.
Estimates of carbon flux to the deep oceans are essential for our understanding of global carbon budgets. Sinking of detrital material ("biological pump") is usually thought to be the main biological component of this flux. Here, we identify an additional biological mechanism, the seasonal "lipid pump," which is highly efficient at sequestering carbon into the deep ocean. It involves the vertical transport and metabolism of carbon rich lipids by overwintering zooplankton. We show that one species, the copepod Calanus finmarchicus overwintering in the North Atlantic, sequesters an amount of carbon equivalent to the sinking flux of detrital material. The efficiency of the lipid pump derives from a near-complete decoupling between nutrient and carbon cycling—a "lipid shunt," and its direct transport of carbon through the mesopelagic zone to below the permanent thermocline with very little attenuation. Inclusion of the lipid pump almost doubles the previous estimates of deep-ocean carbon sequestration by biological processes in the North Atlantic.
National Institute for Aquatic Resources, Oceanography and Climate, Technical University of Denmark, DK-2920 Charlottenlund, Denmark; sjo@aqua.dtu.dk.
Sigrún Huld
http://orcid.org/0000-0003-4985-0447
SH
Jónasdóttir
National Institute for Aquatic Resources, Oceanography and Climate, Technical University of Denmark, DK-2920 Charlottenlund, Denmark; Center for Ocean Life, Technical University of Denmark, DK-2920 Charlottenlund, Denmark;
André W
AW
Visser
Center for Macroecology, Evolution and Climate, Faculty of Science, University of Copenhagen, DK-2100 Copenhagen, Denmark;
Katherine
http://orcid.org/0000-0003-3785-2787
K
Richardson
Department of Mathematics and Statistics, University of Strathclyde, Glasgow G1 1XH, Scotland, United Kingdom.
Michael R
MR
Heath
D025041:Animal Migration / Q000502:physiology*; D000818:Animals; D001267:Atlantic Ocean; D049628:Body Size; D002244:Carbon / Q000032:analysis*; D057965:Carbon Sequestration / Q000502:physiology*; D033342:Copepoda / Q000737:chemistry* / Q000502:physiology*; D008055:Lipids / Q000737:chemistry*
D008055:Lipids; D002244:Carbon
Calanus; annual migration; carbon sequestration; lipid pump; lipid shunt