Spectrophotometric measurements of absorption coefficients by phytoplankton in the Atlantic Southern Ocean during RV POLARSTERN cruise PS103 in Dec 2016 to Jan 2017

Water samples were taken during the Southern Atlantic expedition PS103 with RV Polarstern from 17 Dec 2016 to 28 Jan 2017. Water samples were collected from CTD Niskin bottles at six different depths from the upper 100 to 180 m and additionally from the ship's seawater supply pumped through teflon tubing from about 11m depth during underway further described in Bracher (2019). All collected samples were filtered through 25 cm Whatman GF/F filters, respectively, under low-vacuum pressure (below 200 mbar). Blank filters were collected by soaking them in 0.2um filtered seawater. Measurements for particulate and non-algal (NAP) absorption were performed directly after filtration the quantitative filtration techniques-intergrative cavity measurement device and procedure from Röttgers et al. (2016) as described in Liu et al. (2018). Phytoplankton absorption (aph) was derived by subtracting the NAP from the particulate absorption.