The open-ocean convection in the Southern Adriatic: a controlling mechanism of the spring phytoplankton bloom

Abstract

Physical and chemical data analysed and interpreted jointly with the remotely sensed chlorophyll a concentrations and sediment trap records show that the spring primary production maximum in the Southern Adriatic is determined by the open-sea convection and the formation of the dense Adriatic water. The open-sea convection varies strongly on the interannual time-scale and, in some years, does not occur at all due to mild winter climatic conditions. In those years, the spring bloom and the export production are highly reduced. The spring primary production maximum consists of several intense bloom episodes, which occur in the centre of the cyclonic gyre in calm weather periods following violent mixing events and vertical injections of nutrients in the euphotic zone.