ESSDD Earth System Science Data Discussions ESSDD Earth Syst. Sci. Data Discuss. 1866-3591 Göttingen, Germany 10.5194/essd-2026-144 A Pan-Arctic Pigment Database for Phytoplankton and Sea-Ice Algae Heidemann Asta C. https://orcid.org/0009-0003-4808-2746 1 Hayward Alexander https://orcid.org/0000-0003-3500-9964 2 Assmy Philip 3 Basu Atreya 4 Bracher Astrid https://orcid.org/0000-0003-3025-5517 5 6 Castellani Giulia 6 Ditullio Giacomo https://orcid.org/0000-0002-3088-5423 7 Dragańska-Deja Katarzyna 8 Fujiwara Amane 9 Fragoso Glaucia Moreira 10 Høyer Jacob 2 Hwang Jiwoon 11 Iversen Morten 5 von Jackowski Anabel 12 Juul-Pedersen Thomas https://orcid.org/0000-0002-4249-0752 13 Kowalczuk Piotr https://orcid.org/0000-0001-6016-0610 8 Lee Youngju https://orcid.org/0000-0003-2470-972X 14 Matsuoka Atsushi 15 Merz Alenya 13 16 Mundy C. J. 17 Ostermann Else 13 Peeken Ilka https://orcid.org/0000-0003-1531-1664 5 Pinkerton Matt 18 Stoń-Egiert Joanna https://orcid.org/0000-0002-4274-8979 8 Thielecke Antonia U. https://orcid.org/0009-0005-9584-4699 5 Veyssiere Gaëlle 19 Xi Hongyan https://orcid.org/0000-0003-2827-0603 5 Yang Eun Jin 14 Gonçalves-Araujo Rafael https://orcid.org/0000-0001-8344-8326 1 National Institute of Aquatic Resources, Technical University of Denmark (DTU Aqua), Kgs. Lyngby, Denmark Danish Meteorological Institute Norwegian Polar Institute, Fram Centre, Tromsø, Norway Centre for Earth Observation Science, University of Manitoba, Winnipeg, Canada Alfred-Wegener-Institute Helmholtz Center for Polar and Marine Research (AWI), Bremerhaven, Germany Institute of Environmental Physics (IUP), University Bremen (UB), Bremen, Germany University of Charleston, Grice Marine Laboratory Institute of Oceanology Polish Academy of Sciences, Sopot, Poland Institute of Arctic Climate and Environment Research, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan SINTEF Ocean, Department of Climate and Environment, Trondheim, Norway, 7041 University of California, Berkeley, USA Stockholm University, Stockholm, Sweden Greenland Climate Research Centre (GCRC), Greenland Institute of Natural Resources (GINR), Nuuk, Greenland Korea Polar Research Institute, Incheon, Republic of Korea Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, USA Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, Netherlands Centre for Earth Observation Science, Faculty of Environment, Earth and Resources, University of Manitoba, Winnipeg, Manitoba, Canada Earth Sciences New Zealand, Wellington, New Zealand British Antarctic Survey, Cambridge, Cambridgeshire, UK 24 03 2026 2026 1 33 Copyright: © 2026 Asta C. Heidemann et al. 2026 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://essd.copernicus.org/preprints/essd-2026-144/ The full text article is available as a PDF file from https://essd.copernicus.org/preprints/essd-2026-144/essd-2026-144.pdf

Climate change has dramatically altered the Arctic seas with significant decrease in sea ice extent and thickness and warming water temperature. The ecological impacts of such change have been described for many parts of the Arctic Ocean, but long-term records of biological indicators are still missing. Among those, photosynthetic and accessory pigments are one of the key tools that aid quantification of phytoplankton and sea-ice algae biomass and characterisation of community composition. To address this gap, we present the first pan-Arctic compilation of in situ algal pigment data obtained exclusively by High-Performance Liquid Chromatography (HPLC), containing 10.798 samples collected across 77 Arctic research cruises between 2000 and 2024. As a result of large-scale collaborative effort, this database covers both open water and sea-ice environments across coastal, shelf and open domains. The database (10.11583/DTU.29445104) includes measures of up to 26 pigments, with 8 major marker/accessory pigments being considered in this study, namely Alloxanthin (Allo), 19’-Butanoyloxyfucoxanthin (Butfuco), Chlorophyll a (Chl-a), Chlorophyll b (Chl-b), Fucoxanthin (Fuco), 19’-Hexanoyloxyfucoxanthin (Hexfuco), Peridinin (Peri), and Zeaxanthin (Zea). This publicly available database provides crucial data that can be used to assess phytoplankton dynamics, validating remote sensing observations and can serve as a resource for future Arctic ecological- and modelling studies.

 Danmarks Frie Forskningsfond 4251-00058B HORIZON EUROPE Framework Programme 101136480 Norges Forskningsråd 244646 National Aeronautics and Space Administration 80NSSC26K0091 Japan Aerospace Exploration Agency 25RT000334 Korea Institute of Marine Science and Technology promotion KIMST RS-2021-KS211500 Narodowe Centrum Nauki 2023/51/B/ST10/01344 HORIZON EUROPE Framework Programme 101136748 Deutsche Forschungsgemeinschaft 23138L03D-COP-INNO SCI-9000 European Space Agency 4000147645/25/I-LR Helmholtz Association VH-NG-1600 Helmholtz Association AWI_PS138_02