Major declines in NE Atlantic plankton contrast with more stable populations in the rapidly warming North Sea

• Published in: Science of The Total Environment
• Main Authors: Holland, Matthew, Louchart, Arnaud, Artigas, Luis Felipe, Ostle, Clare, Atkinson, Angus, Rombouts, Isabelle, Graves, Carolyn, Devlin, Michelle, Heyden, Birgit, Machairopoulou, Margarita, Bresnan, Eileen, Schilder, Jos, Jakobsen, Hans, Lloyd-Hartley, Hannah, Tett, Paul, Best, Mike, Goberville, Eric, McQuatters-Gollop, Abigail
• Other Authors: Marine Biological Association, Stazione Zoologica Anton Dohrn (SZN), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD France-Nord ), Université du Littoral Côte d'Opale (ULCO), Plymouth Marine Laboratory (PML), Patrimoine naturel (PatriNat), Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Office français de la biodiversité (OFB), Station marine Dinard, Centre De Recherche et d'Enseignement sur les Systèmes Côtiers (CRESCO), Muséum national d'Histoire naturelle (MNHN)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Muséum national d'Histoire naturelle (MNHN)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Department of Chemistry Simon Fraser University ( SFU.ca ), Faculty of Sciences SFU.ca, Simon Fraser University = Université Simon Fraser (SFU.ca)-Simon Fraser University = Université Simon Fraser (SFU.ca), C2O Consulting, Marine Scotland Marine Laboratory, Aarhus University Aarhus, Scottish Association for Marine Science (SAMS), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Plymouth University
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: Food webs; North Sea; North-East Atlantic; Marine ecosystem management; Pelagic habitats; Plankton; Continuous plankton recorder; Environmental indicators; [SDE]Environmental Sciences; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; [SDE.MCG]Environmental Sciences/Global Changes; North East Atlantic; Copepods
• Online Access: https://hal.science/hal-04193672; https://hal.science/hal-04193672/document; https://hal.science/hal-04193672/file/1-s2.0-S0048969723041281-main.pdf; https://doi.org/10.1016/j.scitotenv.2023.165505

International audience Plankton form the base of marine food webs, making them important indicators of ecosystem status. Changes in the abundance of plankton functional groups, or lifeforms, can affect higher trophic levels and can indicate important shifts in ecosystem functioning. Here, we extend this knowledge by combining data from Continuous Plankton Recorder and fixed-point stations to provide the most comprehensive analysis of plankton time-series for the North-East Atlantic and North-West European shelf to date. We analysed 24 phytoplankton and zooplankton datasets from 15 research institutions to map 60-year abundance trends for 8 planktonic lifeforms. Most lifeforms decreased in abundance (e.g. dinoflagellates: −5 %, holoplankton: −7 % decade−1), except for meroplankton, which increased 12 % decade−1, reflecting widespread changes in large-scale and localised processes. K-means clustering of assessment units according to abundance trends revealed largely opposing trend direction between shelf and oceanic regions for most lifeforms, with North Sea areas characterised by increasing coastal abundance, while abundance decreased in North-East Atlantic areas. Individual taxa comprising each phytoplankton lifeform exhibited similar abundance trends, whereas taxa grouped within zooplankton lifeforms were more variable. These regional contrasts are counterintuitive, since the North Sea which has undergone major warming, changes in nutrients, and past fisheries perturbation has changed far less, from phytoplankton to fish larvae, as compared to the more slowly warming North-East Atlantic with lower nutrient supply and fishing pressure. This more remote oceanic region has shown a major and worrying decline in the traditional food web. Although the causal mechanisms remain unclear, declining abundance of key planktonic lifeforms in the North-East Atlantic, including diatoms and copepods, are a cause of major concern for the future of food webs and should provide a red flag to politicians and policymakers about ...