Exudation of organic carbon by marine phytoplankton: Dependence on taxon and cell size

8 pages, 3 figures, 3 tablesWe determined the relationship between photosynthetic production of dissolved organic carbon (OC) and phytoplankton cell size and taxonomic composition in cultures of marine phytoplankton at 3 different growth stages. We measured OC exudation in 22 species belonging to 5 phyla and spanning >7 orders of magnitude in cell volume. The extracellular release of OC in our cultures represented on average ~2% of total carbon fixation, was not statistically different between growth stages, and was not correlated to cell size. The cell-specific OC exudation rate held an isometric relationship with cell size during the different growth phases (average slope: 0.95), which implies that general allometric models cannot be used to predict exudation in marine phytoplankton. Copyright © Inter-Research 2013This research was funded by the Spanish Ministerio de Educación y Ciencia through the research project ‘Macroecological patterns in marine phytoplankton’ (Grant CTM2008-03699/MAR to E.M.). D.C.L.S. was supported by postgraduate fellowships from the Mexican Council of Science and Technology (CONACyt) and the Xunta de Galicia (Spain)Peer Reviewe