Seasonal variability in living benthic foraminifera across intertidal areas of the eastern English Channel

Abstract. The ecology of benthic foraminifera in tidal flats has been extensively studied at local scales, but its seasonal and spatial dynamics across broader intertidal gradients remain poorly understood. This study investigates seasonal variations in the composition and structure of living benthic foraminiferal assemblages across contrasting intertidal habitats in the eastern English Channel. We analyzed 256 surface sediment samples (192 for foraminifera and 64 for sediment properties) collected over four seasons at various sites in the Hauts-de-France region (northern France) along the eastern English Channel. Multivariate analyses revealed significant seasonal changes in the assemblage structure. Linear discriminant analysis identified two dominant seasonal groups. Opportunistic taxa, such as Haynesina germanica and Ammonia confertitesta, dominate during colder seasons, while more diverse and thermophilic species including Elphidium selseyense, Quinqueloculina dimidiata, and Trochammina inflata characterize warmer months. These findings provide new insights into the phenology of benthic foraminifera and contribute to a better understanding of seasonal ecological processes in temperate intertidal ecosystems.