Spectrophotometric measurements of absorption coefficients by phytoplankton during HEINCKE cruise HE462 in the North Sea and Sogne Fjord from 29 April to 7 May 2016

Water samples were taken during the spring (29 April to 7 May 2016) expedition HE462 with RV Heincke in the North Sea and Sogne Fjord. Water samples were collected from CTD Niskin bottles at six different depths from the upper 100 m at 17 Stations and additionally from the ship's seawater supply pumped through teflon tubing from about 5m depth during underway. As for phytoplankton pigments (see Bracher and Wiegmann 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, ap and aNAP, respecitely, 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.