The effect of a strong warm year on zooplankton biomass and indices of grazing, respiration, and growth in subtropical waters.

Abstract

Mesozooplankton biomass, as dry weight, and indices of grazing (gut fluorescence), respiration (elec- tron transfer system activity) and growth (aminoacyl-tRNA synthetases activity), were measured from February to June 2010 in the oceanic waters north off the Canary Islands. Temperature was always above 19ºC, promoting a strong stratification and quite low values of chlorophyll during winter-spring. The late winter bloom, typical in these waters, was not observed. The indices of grazing and respiration showed low values compared to previous years. However, relatively higher mesozooplankton biomass was ob- served during the post bloom period. This paradox was explained by the input of dust deposition from the Sahara desert. These findings show how climatic warming and dust events may interact affecting the intensity of the winter-spring bloom in subtropical waters.