Vertical Migration and Distribution of Zooplankton along a Latitudinal Transect in the Eastern North Atlantic

Abstract

Zooplankton are diverse animals found in the ocean, ranging from microscopic to larger invertebrates, and they are crucial to marine ecosystems. Some zooplankton species migrate vertically towards the oxygen-poor waters during the day, which could affect oxygen consumption and release of dissolved compounds, such as ammonium, into deep water. This study provides an overview of zooplankton distribution in the eastern North Atlantic Ocean. Zooplankton was sampled depth stratified along a transect from Cabo Verde to the English Channel using a 150 μm multinet. An analysis of taxon composition identified 11 taxa. Copepoda and Sagittoidea were the most abundant organisms. Stations located in upwelling areas had high biomasses. Stations sampled at night had higher abundances than those sampled during the day. Hydroacoustic data from the EK80 indicated that organisms migrated vertically between day and night. Biomass in the oxygen minimum zone (OMZ) was high.