Bacterial and phytoplankton abundances by flow cytometry - collected from the Southern Ocean in the austral summer of 2016/2017, during the Antarctic Circumnavigation Expedition.

Seawater surface samples (5 m) were collected every 6 hours from the ship’s underway pump. In addition, vertical profiles (6 depths, generally from 5 to 100-150 m) were sampled from CTD casts using a SBE 911 Plus attached to a rosette of 24 12-L PVC Niskin bottles. This dataset presents the abundances of high-DNA containing and low-DNA containing bacteria, pico and nanophytoplankton from seawater samples collected from the ship’s underway pump and CTDs.  Samples were fixed with paraformaldehyde and glutaraldehyde and stored at -80ºC. In the lab, they were thawed, and one replicate, for bacteria, was stained with SYBR-Green and counted in a Cube 8 flow cytometer (SYSMEX PARTEC) based on green fluorescence. Another replicate was analyzed without staining for phytoplankton, and counted based on the red and orange autofluorescences. Samples were collected around the Southern Ocean on the R/V Akademik Tryoshnikov in the austral summer of 2016/2017, as part of the Antarctic Circumnavigation Expedition (ACE).