Zooplancton respiration in the meso- and bathypelagic layers in the Atlantic Ocean

Abstract

Estimating zooplankton respiration in the mesopelagic layer is crucial for understanding carbon transport in the ocean. The diurnal respiration of vertical zooplankton migrants contributes to the downward flux of carbon in the oceans. Thus, zooplankton respiration directly influences the export and sequestration of organic carbon in the mesopelagic layer, which influences global carbon dynamics. However, measuring specific values of zooplankton respiration in the meso- and bathypelagic zones is challenging. This study examines the respiration of several zooplankton groups in the meso- (200-1000 m) and bathypelagic (>1000 m) layers during the most productive season (winter) in the subtropical Atlantic Ocean due to maximum mixing of the water column. Sampling was conducted at two different latitudinal and longitudinal stations in the North Atlantic Ocean during day and night. The results highlight the importance of incorporating the active transport of large zooplankton migrants in the assessment of the biological carbon pump.