Gradients of mesozooplankton biomass and ETS activity in the wind-shear area as evidence of an Island mass effect in the Canary Island waters

Abstract

Mesozooplankton biomass (displacement volume and proteins) and electron transport system (ETS) activity have been studied around Gran Canaria (Canary Islands) in the wind-shear field of the island. Twenty-seven samples were taken after a period of strong north trade winds (>5 m s −1 ) Biomass and ETS gradients were observed on the island shelf close to the wind-shear field, at the boundary between the turbulent and calm waters in the wake of the island. Biomass gradient values were about three times higher than those found off the island shelf and twice as high as those to the north of the island. ETS activity, on a volume basis, shows a similar result, which is not observed for the specific activity. The development of gradients and their relation to an island mass effect are discussed. Significant differences were found between the values obtained along an oceanic transect to the south of the Archipelago and in the coastal waters around Gran Canaria.