Data was collected in a project investigating the importance of prokaryotic maintenance respiration in the marine environment. Prokaryotic respiration, growth and abundance was measured at multiple stations encompassing three sites along the Baltic Sea gradient and North Sea. Salinity covered 3 to 30. Temperature, total dissolved phosphorus and nitrogen were also measured. Measurements were done during the late summer in August and September 2017. Data from the northern most site was collected 2015 with the same methods. Duplicate Niskin bottle samples were taken from discrete depths in surface waters covering up to 70 m depth depending on site. Prokaryotic respiration was measured in 1.2 µm pre-filtered samples using oxygen optode. Prokaryotic growth was measured by the tritiated thymidine incorporation technique in pre-filtered samples. Prokaryotic abundance was measured by acridine orange stain and direct epi-fluorescence microscopy applying image analysis. Cell-specific respiration and growth rates were calculated for evaluating influence of prokaryotic maintenance respiration. The prokaryotic growth efficiency was also estimated. Results are reported in a scientific article in Frontiers in marine Science (doi:10.3389/fmars.2023.1070070).