Articles | Volume 13, issue 22
Research article
21 Nov 2016
Research article |  | 21 Nov 2016

A novel approach reveals high zooplankton standing stock deep in the sea

Alexander Vereshchaka, Galina Abyzova, Anastasia Lunina, Eteri Musaeva, and Tracey Sutton

Abstract. In a changing ocean there is a critical need to understand global biogeochemical cycling, particularly regarding carbon. We have made strides in understanding upper ocean dynamics, but the deep ocean interior (> 1000 m) is still largely unknown, despite representing the overwhelming majority of Earth's biosphere. Here we present a method for estimating deep-pelagic zooplankton biomass on an ocean-basin scale. We have made several new discoveries about the Atlantic, which likely apply to the world ocean. First, multivariate analysis showed that depth and Chl were the basic factors affecting the wet biomass of the main plankton groups. Wet biomass of all major groups was significantly correlated with Chl. Second, zooplankton biomass in the upper bathypelagic domain is higher than expected. Third, the majority of this biomass comprises macroplanktonic shrimps, which have been historically underestimated. These findings, coupled with recent findings of increased global deep-pelagic fish biomass, suggest that the contribution of the deep-ocean pelagic fauna for biogeochemical cycles may be more important than previously thought.

Short summary
Our primary finding of increased plankton biomass in the deep sea suggests that energy transfer efficiency from phytoplankton to intermediate and higher trophic levels has been underestimated, and that global carbon models need to account for the large portion of oceanic primary production that zooplankton is likely respiring in the deep-pelagic realm.
Final-revised paper