title: Historical records from dated sediment cores reveal the multidecadal dynamic of the toxic dinoflagellate Alexandrium minutum in the Bay of Brest (France).
abstract: The multiannual dynamic of the cyst-forming and toxic marine dinoflagellate Alexandrium minutum was studied over a time scale of about 150 years by a paleoecological approach based on ancient DNA (aDNA) quantification and cyst revivification data obtained from two dated sediment cores of the Bay of Brest (Brittany, France). The first genetic traces of the species presence in the study area dated back to 1873 ± 6. Specific aDNA could be quantified by a newly developed real-time PCR assay in the upper core layers, in which the germination of the species (in up to 17-19-year-old sediments) was also obtained. In both cores studied, our quantitative paleogenetic data showed a statistically significant increasing trend in the abundance of A. minutum ITS1 rDNA copies over time, corroborating three decades of local plankton data that have documented an increasing trend in the species cell abundance. By comparison, paleogenetic data of the dinoflagellate Scrippsiella donghaienis did not show a coherent trend between the cores studied, supporting the hypothesis of the existence of a species-specific dynamic of A. minutum in the study area. This work contributes to the development of paleoecological research, further showing its potential for biogeographical, ecological and evolutionary studies on marine microbes.
authors.affiliation: Ifremer-Centre de Brest, DYNECO PELAGOS, BP 70 ZI Pointe du Diable, F-29280 Plouzané, France Sorbonne Universités, UPMC Univ. Paris 6, CNRS, Adaptation et Diversité en Milieu Marin (UMR 7144), équipe DIPO, Station Biologique de Roscoff, Place Georges Teissier, CS90074, 29688 Roscoff cedex, France.
authors.forename: Khadidja Z
authors.initials: KZ
authors.lastname: Klouch
authors.affiliation: UMR5805 EPOC, University of Bordeaux, 33605 Pessac, France.
authors.forename: Sabine
authors.initials: S
authors.lastname: Schmidt
authors.affiliation: Ifremer-Centre de Brest, DYNECO PELAGOS, BP 70 ZI Pointe du Diable, F-29280 Plouzané, France.
authors.forename: Françoise
authors.initials: F
authors.lastname: Andrieux-Loyer
authors.affiliation: Ifremer-Centre de Brest, DYNECO PELAGOS, BP 70 ZI Pointe du Diable, F-29280 Plouzané, France.
authors.forename: Mickaël
authors.initials: M
authors.lastname: Le Gac
authors.affiliation: Ifremer, RBE, SG2M, Laboratoire Santé, Environnement et Microbiologie, 29280 Plouzané, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Hervio-Heath
authors.affiliation: Ifremer-Centre de Brest, DYNECO PELAGOS, BP 70 ZI Pointe du Diable, F-29280 Plouzané, France.
authors.forename: Zujaila N
authors.initials: ZN
authors.lastname: Qui-Minet
authors.affiliation: Ifremer-Centre de Brest, DYNECO PELAGOS, BP 70 ZI Pointe du Diable, F-29280 Plouzané, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Quéré
authors.affiliation: Sorbonne Universités, UPMC Univ. Paris 6, CNRS, Adaptation et Diversité en Milieu Marin (UMR 7144), équipe DIPO, Station Biologique de Roscoff, Place Georges Teissier, CS90074, 29688 Roscoff cedex, France.
authors.forename: Estelle
authors.initials: E
authors.lastname: Bigeard
authors.affiliation: Sorbonne Universités, UPMC Univ. Paris 6, CNRS, Adaptation et Diversité en Milieu Marin (UMR 7144), équipe DIPO, Station Biologique de Roscoff, Place Georges Teissier, CS90074, 29688 Roscoff cedex, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Guillou
authors.affiliation: Ifremer-Centre de Brest, DYNECO PELAGOS, BP 70 ZI Pointe du Diable, F-29280 Plouzané, France raffaele.siano@ifremer.fr.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Siano
mesh_terms: D061006:Bays; D004275:DNA, Ribosomal / Q000235:genetics; D004141:Dinoflagellida / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D017753:Ecosystem; D005602:France; D019015:Geologic Sediments / Q000737:chemistry / Q000469:parasitology*; D049673:History, 20th Century; D049674:History, 21st Century; D010162:Paleography / Q000266:history; D060888:Real-Time Polymerase Chain Reaction; D013045:Species Specificity
chemical_list: D004275:DNA, Ribosomal
keywords: ancient DNA; coastal ecology; dinoflagellates; harmful algal blooms (HAB); paleoecology; real-time PCR