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Communication Dans Un Congrès Année : 2023

Temporal changes in intertidal benthic foraminifera: a seasonal survey from the English Channel (France)

Résumé

Intertidal ecosystems are fragile environments that are naturally stressed by high spatial and temporal variability of physico-chemical parameters. In addition, these environments have been increasingly affected by the consequences of global warming and the associated rise in mean sea level, heatwaves. The intertidal areas of the Hauts-de-France (English Channel, France) stand out for the occurrence of vulnerable ecosystems that have experienced natural and human–induced stresses. Over the last two centuries, the northern part of this region has been exposed to a strong human pressure, with the development of numerous activities (i.e., metallurgic factories, fisheries, embankments). On the contrary, its southern part includes less impacted areas. The objectives of this study are: 1) to characterise the seasonal variations in abundance (i.e., foraminiferal density, FD) and diversity of benthic foraminifera and 2) to identify which species are the most frequent and their temporal variations in this region based on a one-year survey. Sixteen sampling stations were selected from five sampling areas along the intertidal zones of Hauts-de-France with different levels of humanisation. At each of the four seasons (spring 2014; summer 2014; autumn 2014; and winter 2015), four replicated sediment samples were collected at each station. Three replicates were used for the foraminiferal analysis and the fourth was used to measure abiotic parameters (i.e., grain-size, total organic carbon, C/N ratio), collecting 256 samples (192 for foraminifera and 64 for sediment properties). Statistical analyses (i.e., Krustal-Wallis test and PERMANOVA) were carried out to reveal any significant influence of seasonality on foraminiferal assemblages. Significant seasonal variations were observed for FD although it did not show a clear temporally trend across the region. The diversity showed a significant seasonal influence with the highest values commonly found during spring and summer. For both FD and diversity, different patterns were exhibited in natural and human–altered stations. Haynesina germanica and Elphidium selseyense were the most frequent species differently distributed across the region. They both showed significant seasonal variations. The overall outcomes of this survey shed light on complex seasonal patterns in benthic communities of intertidal environments. Furthermore, this study evidences the importance of baseline and temporal investigations to plan further environmental monitoring of ongoing climate and humanrelated changes in the intertidal settings.
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Dates et versions

ujm-04541405 , version 1 (10-04-2024)

Identifiants

  • HAL Id : ujm-04541405 , version 1

Citer

Fabio Francescangeli, Vincent M.P. Bouchet, Yvonne Milker, Fabrizio Frontalini, Xavier Richard, et al.. Temporal changes in intertidal benthic foraminifera: a seasonal survey from the English Channel (France). FORAMS 2023, Jun 2023, Perugia (Italy), France. ⟨ujm-04541405⟩
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