Areal data from summer 2004 and winter 2006 cruises.

All parameters for the summer cruise have been integrated over the entire euphotic layer (1% incident PAR at surface; it was similar to the mixed layer depth or deeper). The winter PP has been integrated over the euphotic layer while other parameters have been integrated over the mixed layer depth (epipelagic) and from there down to 750 m (mesopelagic layer). Averages and standard deviation in parenthesis.PP = primary production; BCP = bacterial carbon production; Summer excess DOC = summer dissolved organic carbon values minus average winter constant value (36.5±2.8 µM C s.d.); BCD = bacterial carbon demand (BCP/bacterial growth efficiency); N.D. = not determined.*BCD calculated using a bacterial growth efficiency derived by the curve in ref. [20] (∼36% in summer and 39% in winter).**BCD calculated using bacterial growth efficiency of 13% in summer and 6.2% in winter (averaging all data for summer and only HNLC for winter from [12]).§no s.d. reported because the value is derived from a single depth profile.°DOC data for winter are not reported, since they are considered as constant refractory DOC values, and have been used to determine summer excess DOC.