title: Impact of seaweed beachings on dynamics of δ(15)N isotopic signatures in marine macroalgae.
abstract: A fine-scale survey of δ(15)N, δ(13)C, tissue-N in seaweeds was conducted using samples from 17 sampling points at two sites (Grandcamp-Maisy (GM), Courseulles/Mer (COU)) along the French coast of the English Channel in 2012 and 2013. Partial triadic analysis was performed on the parameter data sets and revealed the functioning of three areas: one estuary (EstA) and two rocky areas (GM(∗), COU(∗)). In contrast to oceanic and anthropogenic reference points similar temporal dynamics characterized δ(15)N signatures and N contents at GM(∗) and COU(∗). Nutrient dynamics were similar: the N-concentrations in seawater originated from the River Seine and local coastal rivers while P-concentrations mainly from these local rivers. δ(15)N at GM(∗) were linked to turbidity suggesting inputs of autochthonous organic matter from large-scale summer seaweed beachings made up of a mixture of Rhodophyta, Phaeophyta and Chlorophyta species. This study highlights the coupling between seaweed beachings and nitrogen sources of intertidal macroalgae.
authors.affiliation: Normandie Université, Université de Caen Basse-Normandie, F-14032 Caen, France; UMR BOREA, CNRS-7208, IRD-207, MNHN, UPMC, UniCaen, Esplanade de la Paix, F-14032 Caen, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Lemesle
authors.affiliation: Normandie Université, Université de Caen Basse-Normandie, F-14032 Caen, France; UMR BOREA, CNRS-7208, IRD-207, MNHN, UPMC, UniCaen, Esplanade de la Paix, F-14032 Caen, France. Electronic address: isabelle.mussio@unicaen.fr.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Mussio
authors.affiliation: Normandie Université, Université de Caen Basse-Normandie, F-14032 Caen, France; UMR BOREA, CNRS-7208, IRD-207, MNHN, UPMC, UniCaen, Esplanade de la Paix, F-14032 Caen, France.
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Rusig
authors.affiliation: IFREMER, Laboratoire Environnement Ressources de Normandie, Avenue du Général de Gaulle, 14520 Port-en-Bessin, France.
authors.forename: Florence
authors.initials: F
authors.lastname: Menet-Nédélec
authors.affiliation: Normandie Université, Université de Caen Basse-Normandie, F-14032 Caen, France; UMR BOREA, CNRS-7208, IRD-207, MNHN, UPMC, UniCaen, Esplanade de la Paix, F-14032 Caen, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Claquin
mesh_terms: D002247:Carbon Isotopes / Q000032:analysis; D000460:Chlorophyta / Q000737:chemistry; D063366:Estuaries; D005602:France; D009584:Nitrogen / Q000032:analysis; D009587:Nitrogen Isotopes / Q000032:analysis*; D000459:Phaeophyceae / Q000737:chemistry; D010758:Phosphorus / Q000032:analysis; D000461:Rhodophyta / Q000737:chemistry; D045483:Rivers; D012621:Seasons; D012623:Seawater; D012624:Seaweed / Q000737:chemistry*
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes; D010758:Phosphorus; D009584:Nitrogen
keywords: Bay of Seine; English Channel; Macroalgae; Seasonality; Tissue-N; δ(15)N