The mesopelagic food web

Organisms in the mesopelagic zone are crucial players in the “biological pump”, a process whereby organic carbon from surface waters is exported to the deep-sea. This process acts as a climate buffer because once in the deep sea, organic carbon may remain there for long periods of time, and less carbon dioxide returns to the atmosphere.

One of the factors affecting the overall organic biomass reaching the ocean floor is the food web. Mesopelagic fish are poised to play a large role in the biological pump because they are so abundant, and they undergo daily migrations to surface waters to feed on zooplankton.

The nature of the food web interactions, that may change with seasons, between species, and with the quality and quantity of available prey, all have the capacity to affect carbon export to depth. We will be using a combination of DNA and fatty acid analyses to establish the diets of mesopelagic fish off British Columbia, Canada.