ZOOPLANKTON DISTRIBUTION AND METABOLISM IN THE WESTERN
ALBORAN SEA, IMPLICATIONS FOR EXPORT FLUXES
Lidia Yebra, Inma Herrera, Jesús M. Mercado, Dolores Cortés, Aitor Alonso, Francisco
J. Gómez, Antonio Sánchez, Soluna Salles and Nerea Valcárcel
Instituto Español de Oceanografía, Centro Oceanográfico de Málaga, Puerto pesquero
s/n, 29640 Fuengirola, Málaga, Spain.
ABSTRACT
Distribution of marine productivity in the Alboran Sea responds strongly to its
hydrodynamics, shaped by the influence of the Atlantic jet that enters through the
Gibraltar Strait. This stream originates an anticyclonic gyre in the centre of the
occidental basin. The gyre is characterised by low average surface nutrient and
chlorophyll a concentrations, with occasional peaks of high phytoplankton production.
However, little is known about the role of zooplankton in the productivity and export
fluxes in the gyre. We studied vertical distribution (0-900 m) of zooplankton biomass
and indices of grazing (gut fluorescence), potential respiration (ETS activity) and
growth (AARS activity) rates from the Spanish coast towards the anticyclonic gyre.
Zooplankton biomass was generally distributed in distinctive layers and we observed
strong diel vertical migrations in the mesopelagic domain. The contribution of migrant
zooplankton to the carbon export fluxes is discussed in relation to the variations
observed in their biomass and metabolism across the study area.