1. Dataset Title: Data for contribution of marine phytoplankton and bacteria to ocean alkalinity 2. Author(s) 1) Kitack Lee, Pohang University of Science and Technology, ktl@postech.ac.kr 2) Chang-Ho Lee, Pohang University of Science and Technology, lch6261@postech.ac.kr 3. Funding 1) Ministry of Science and ICT, South Korea : NRF-2021R1A2C3008748 2) National Institute of Fisheries Science : R2021051 4. File List 1) Data_for_depth_profile.xlsx (data for 24 samples collected at two sites (76.003ºN, 170.588ºW; 74.499ºN, 162.262ºW) in the Arctic Ocean) 2) Data_for_surface_samples.xlsx (data for 205 samples collected underway from the East Sea to the North Pacific Ocean, the Bering Sea, the Chukchi Sea, and the Arctic Ocean) 5. Information for parameters 1) Data_for_depth_profile.xlsx Sampling location : Sample collection location in latitude and longitude Depth (m) : Depth of seawater sample collection AT (μmol kg–1) : Total alkalinity measured for seawater sample AT-BIO (μmol kg–1) : Contribution of phytoplankton and bacteria to total alkalinity in seawater sample 2) Data_for_surface_sample.xlsx Sampling Basins : Basins where seawater sample collected (the East Sea, the North Pacific Ocean, the Bering Sea, the Chukchi Sea, or the Arctic Ocean) Latitude (ºN) : Latitude of the seawater sample collection Longitude (ºN) : Longitude of the seawater sample collection Temp. (ºC) : In situ temperature of the seawater sample Salinity (‰) : Salinity of the sawater sample AT (μmol kg–1) : Total alkalinity measured for seawater sample AT-BIO (μmol kg–1) : Contribution of phytoplankton and bacteria to total alkalinity in seawater sample AT-PLANKTON (μmol kg–1) : Contribution of phytoplankton to total alkalinity in seawater sample AT-BACTERIA (μmol kg–1) : Contribution of bacteria to total alkalinity in seawater sample POC (μmol kg–1) : Concentration of particulate organic carbon in seawater sample N.A. : Not available