Phytoplankton pigments composition and concetrations measured with HPLC methods in water samples collected in the Amundsen and Nansen basins of the Arctic Ocean in July/August 2024.

This data sets contains phytoplankton pigment concentrations (g dm-3) obtained by use of HPLC technique from samples collected during the Arctic Ocean 2024 cruise (AO2024, Dodd et al., 2024), on board of the research icebreaker r/v Kronprins Haakon, between 19 July - 12 August 2024. Its main goals were to collect a transect of physical, chemical, and biological observations of the ocean and sea ice across the western Amundsen and Nansen basins of the Arctic Ocean. Water samples were collected at three depths, at the surface, at the Deep Chlorophyll-a Maximum (DCM) and 50 m, at the main coupled physical and biological stations. The depth at which the DCM was located was determined from chlorophyll-a fluorescence profile measured by the standard fluorometer attached to the ship’s CTD rosette. On secondary stations samples were collected at standard horizons, 10, 25, and 50 m. Collected water samples were filtered onboard using Whatman filters (GF/F, 25 mm). Filters with the retained material were stored in liquid nitrogen or in deep-freeze conditions until the measurements. Measurements were performed in the land based laboratory in the Institute of Oceanology Polish Academy of Sciences, Sopot, Poland. In the first step of analyses pigments were isolated from algae cells by mechanical grinding and sonication (2 min, 20 kHz, Cole Parmer, 4710 Series) in the darkness conditions at 4 ºC during 2 hours with use of 90% acetone solution (Parsons et al. 1984). After centrifugation (20 min., 5 ºC, 3210xg, Beckman, GS-6R) to remove the filters and cellular debris, extract was subjected to the chromatographic analysis. The chromatographic system HP1200 (Agilent, Perlan Technologies) was equipped with diode array absorbance detector, fluorescence detector and C18 LichroCART™LiChrospher™ 100 RP18e (Merck) analytical column (dimension 250 x 4 mm, particle size 5 μm and pore size 100 Å). The pigments separation, qualification and quantification was performed according to methodology presented in Stoń-Egiert and Kosakowska 2005. Calibration of chromatographic system was based on commercially available chlorophylls and carotenoids (The International Agency for 14C Determination DHI Institute for Water and Environment in Denmark).

Dodd, P. A., Wold, A., Ahmed, F., Darecki, M., Duncan, R., Fossan, K., Goraguer, L., Granskog, M., Itkin, P., Kern, Y., Koenig, Z., Kohlbach, D., Kovacs, K., Kowalczuk, P., Christensen, J., Leu, E., Lydersen, C., Muilwijk, M., Nowak, B., . . . Helgerud, T. L. S. Arctic Ocean 2024 cruise report: 19 July - 12 August 2024 (cruise ID: 2024007009). https://hdl.handle.net/11250/3145717, 2024

Parsons TR, Maita Y, Lalli CA (1984) A manual of chemical and biological methods for seawater analysis. Pergamon Press, Oxford

Stoń-Egiert J, Kosakowska A (2005) RP-HPLC determination of phytoplankton pigments – comparison of calibration results for two columns. Mar Biol 147:251–260.