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The intertidal areas of the Hauts-de-France (English Channel - France) stand out for the occurrence of fragile ecosystems that are exposed to natural and human-induced stress. Over the last two centuries, the northern part of this region has experienced a strong human pressure, with the settlement of numerous activities (i.e., metallurgic factories, harbors, embankments). On the contrary, the southern part includes mostly natural areas. The whole region is influenced by a macrotidal regime. A multidisciplinary approach based on sedimentological (grain-size), geochemical (trace metals, biomarkers) and biological (foraminifera) proxies was used to unravel the contrasting environmental conditions in the Hauts-de-France. Three foraminiferal-types communities, which reflect different ecological characteristics at regional scale, were identified: 1) estuarine macrotidal assemblages (Haynesina germanica associated to Elphidiidae) in low impacted estuaries; 2) industrial-perturbed assemblages (H. germanica and Cribroelphidium excavatum) in harbor areas; and 3) infaunal-dominant assemblages (Bolivina variabilis and B. pseudoplicata) in embankment areas. The outcomes of this study show that a multiproxy procedure needs to be adopted for properly characterizing intertidal ecosystems, where human impacts and natural stresses overlap and are hard to disentangle., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

On the basis of the available databases including 700 sampling stations from subtidal to salt marsh areas, the purpose of this paper is to synthesise the regional distribution of living benthic foraminifera in transitional environments along the English Channel and southern North Sea. Indicator species analyses assign 37 foraminiferal taxa to high salt marsh, middle salt marsh, low salt marsh, tidal flat, tidal channel, and subtidal environmental units. Species are indicator of a single unit (e.g., Elphidium gunteri for tidal flat) up to four units (e.g., Haynesina germanica from tidal flat to middle marsh). The outcomes of the present study enhance future high-resolution paleo-environmental interpretations based on benthic foraminifera in transitional environments., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Over the last centuries, coastal areas have experienced dramatic degradations of their environmental quality, which has led to a huge reduction of marine biodiversity. The objective of the present study was to use geochemical parameters and benthic fossil foraminifera to assess environmental changes that have occurred over the last 200 years in a harbour area (Boulogne-sur-Mer, Northern France) heavily modified by human activities. A multidisciplinary approach including major and trace metals, grain-size, total organic carbon and benthic fossil foraminifera, has been performed on a 33-cm long core. The dating was carried out using the activity of (210)Pb and (137)Cs. Embayment of the area and increase of trace metals concentrations induced a shift in benthic communities. Human activities modified a sandy nearshore bank, colonized by typical marine foraminiferal species, such as Cribroelphiudium excavatum, into a sheltered environment, dominated by brackish end-members, such as Haynesina germanica. Along the sedimentary record, the interaction between meiofaunal and geochemical elements made it possible to distinguish between a pre-impacted period and an industrial period. The upper part of the core reflects better ecological conditions, indicating an environmental recovery. Our results provide baselines for future environmental bio-monitoring in the area., (Copyright © 2016 Elsevier Ltd. All rights reserved.)