Functional Diversity of Phytoplankton in the Mediterranean Sea: Environmental Forcing on Cell Size and Ecophysiology

Size is a crucial biological trait that determines the metabolism and energy fluxes in cells through resources requirement and acquisition, as well as the “susceptibility” of cells to environmental changes. The aim of our contribution is to do a synthesis of the relations between size – pico vs nano+microphytoplankton – and environmental forcings that have been investigated in different trophic conditions of the Mediterranean sea as well as from laboratory experiments. Different time and space scales are analyzed, from the large basin scale to mixed layer or deep-chlorophyll maximum. A strong discrimination between picoplankton and the rest of the community is highlighted both at the level of the ecological pattern and on their ecophysiological behavior.