This dataset includes measured and calculated data over the epipelagic layer (0-200 m depth) of 25 stations with 14 of them inside or in the vicinity of a cyclonic eddy that formed off Mauritania along the ∼ 900 km zonal corridor between Mauritania and the Cabo Verde islands in the eastern Tropical North Atlantic during the M156 cruise on the RV Meteor from July 3rd to August 1st 2019. Bacterial biomass production rates were measured through the incorporation of labelled leucine (3H) using the microcentrifuge method (Kirchman et al., 1985, https://doi.org/10.1128/aem.49.3.599-607.1985; Smith and Azam, 1992). Bacteria carbon demand and growth efficiency were calculated from bacterial production and respiration rates. Dittmar, T., Cherrier, J., and Ludwichowski, K. U.: The analysis of amino acids in seawater, in: Practical guidelines for the analysis of seawater, edited by: Wurl, O., 67–78, CRC Press, Boca Raton, ISBN: 978-1-4200-7306-5, 2009. Evans, C. A., O'Reily, J. E., and Thomas, J. P.: A handbook for measurement of Chl a and primary production, College Station, TX, Texas A and M University, ISBN:9780948277078, 0948277076, 1987. Gargas, E.: A Manual for Phytoplankton Primary Production Studies in the Baltic, The Baltic Marine Biologists, 2, 88 pp. Ed. Gargas E. (Hørsholm, Denmark: Water Quality Institute), 1975. Smith, D. and Azam, F.: A simple, economical method for measuring bacterial protein synthesis rates in seawater using, Mar. Microb. Food Webs, 6, 107–114, 1992.

Bacterial production was convert from leucine/kg to µmol/L using a conversion factor of 1.55 kgC/mol of Leucine. BP and CR ex-situ rates were recalculate to 22°C. BR_22°C was obtained from CR at 22°C.