Zooplankton and the Biological Carbon Pump

Every year, large numbers of zooplankton migrate from the surface of the ocean to depths of 500 – 2000 m to hibernate. Through this migration, they actively transport organic carbon to the deep ocean, where it is used to fuel metabolic needs. This active transport of carbon is thought to be highly efficient, as carbon metabolized by copepods is directly injected deep into the ocean's interior. The significance of this process in view of global carbon cycling remains an open question. Out of the ~30 species of copepods that are known to perform seasonal vertical migrations globally, a preliminary analysis found enough information to compute carbon export and sequestration for only five of them, primarily located in the North Atlantic and the Southern Ocean. We found that the diapause of these five species were responsible for 0.4 – 0.8% of the global carbon export, and between 0.8 – 3.3% of total carbon sequestration.