Seasonality and interannual variability of copepods in the Western English Channel, Celtic Sea, Bay of Biscay, and Cantabrian Sea with a special emphasis to Calanus helgolandicus and Acartia clausi

• Published in: ICES Journal of Marine Science
• Main Authors: Valdés, Luis, López-Urrutia, Angel, Beaugrand, Gregory, Harris, Roger, P, Irigoien, Xabier
• Other Authors: Instituto Español de Oceanografía (IEO), Consejo Superior de Investigaciones Cientificas = Spanish National Research Council (CSIC), 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 ), Plymouth Marine Laboratory (PML)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: Acartia clausi; Bay of Biscay; Calanus helgolandicus; Cantabrian Sea; Celtic Sea; copepods; NAO; time series analysis; Western English Channel; zooplankton; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; [SDV.BA.ZI]Life Sciences [q-bio]/Animal biology/Invertebrate Zoology; North Atlantic; North Atlantic oscillation; Copepods
• Online Access: https://hal.science/hal-04290773; https://hal.science/hal-04290773/document; https://hal.science/hal-04290773/file/Valdes%20et%20al%202022.pdf; https://doi.org/10.1093/icesjms/fsac052

A total of five mesozooplankton time series data sets were assembled to compare the seasonal and interannual patterns of abundance of calanoid copepods in the Western English Channel (Station L4), Celtic Sea, Bay of Biscay (Continuous Plankton Recorder), and the Cantabrian Sea (RADIALES time series, Santander, St-4 and St-6) from January 1992 to December 1999. A strong seasonal component in taxonomic composition was detected at the locations considered. There was also a strong latitudinal effect on diversity at each location, southernmost locations being more diverse. The seasonal dynamics and year-to-year variability of two copepod species: Calanus helgolandicus and Acartia clausi were studied in detail. A latitudinal pattern in the seasonal cycles of both copepod species was observed. The peaks of both occur earlier in spring in the warmer southern region and move northwards, consistent with the temperature regimes at each location, supporting the broad concept that species occupy a thermal niche in time as well as in space. There was a strong degree of interannual variability between sites and between species. No clear trends, but some coherent events among data sets, reveal a regional response to environmental forcing factors. Correlations suggest possible connections with environmental indices like the North Atlantic Oscillation and the Gulf Stream North Wall index. There was a positive correlation between the NAO and the abundance of C. helgolandicus at station L4 off Plymouth; however, the relationship in the Celtic Sea and Bay of Biscay was opposite to that expected based on previous results. Despite the differences in the sampling techniques used within each dataset, the results are comparable and coherent in terms of taxonomic composition and the seasonal and interannual patterns detected.