Phytoplankton Diversity and Community Composition along the Estuarine Gradient of a Temperate Macrotidal Ecosystem: Combined Morphological and Molecular Approaches
Microscopical and molecular analyses were used to investigate the diversity and spatial community structure of spring phytoplankton all along the estuarine gradient in a macrotidal ecosystem, the Baie des Veys (eastern English Channel). Taxa distribution at high tide in the water column appeared to be mainly driven by the tidal force which superimposed on the natural salinity gradient, resulting in a two-layer flow within the channel. Lowest taxa richness and abundance were found in the bay where Teleaulax-like cryptophytes dominated. A shift in species composition occurred towards the mouth of the river, with the diatom Asterionellopsis glacialis dramatically accumulating in the bottom waters of the upstream brackish reach. Small thalassiosiroid diatoms dominated the upper layer river community, where taxa richness was higher. Through the construction of partial 18S rDNA clone libraries, the microeukaryotic diversity was further explored for three samples selected along the surface salinity gradient (freshwater - brackish - marine). Clone libraries revealed a high diversity among heterotrophic and/or small-sized protists which were undetected by microscopy. Among them, a rich variety of Chrysophyceae and other lineages (e.g. novel marine stramenopiles) are reported here for the first time in this transition area. However, conventional microscopy remains more efficient in revealing the high diversity of phototrophic taxa, low in abundances but morphologically distinct, that is overlooked by the molecular approach. The differences between microscopical and molecular analyses and their limitations are discussed here, pointing out the complementarities of both approaches, for a thorough phytoplankton community description.
Université de Caen Basse-Normandie, UMR BOREA “Biologie des Organismes et Ecosystèmes Aquatiques,” Caen, France;Centre National de la Recherche Scientifique (CNRS), Institut Ecologie et Environnement (INEE), UMR BOREA, Caen, France;Algobank-Caen, Université de Caen Basse-Normandie, Caen, France;Department Experimentelle Phykologie und Sammlung für Algenkulturen (EPSAG), Georg-August-Universität Göttingen, Göttingen, Germany;Université de Caen Basse-Normandie, UMR BOREA “Biologie des Organismes et Ecosystèmes Aquatiques,” Caen, France;Centre National de la Recherche Scientifique (CNRS), Institut Ecologie et Environnement (INEE), UMR BOREA, Caen, France;Université de Caen Basse-Normandie, UMR BOREA “Biologie des Organismes et Ecosystèmes Aquatiques,” Caen, France;Centre National de la Recherche Scientifique (CNRS), Institut Ecologie et Environnement (INEE), UMR BOREA, Caen, France;Université de Caen Basse-Normandie, UMR BOREA “Biologie des Organismes et Ecosystèmes Aquatiques,” Caen, France;Centre National de la Recherche Scientifique (CNRS), Institut Ecologie et Environnement (INEE), UMR BOREA, Caen, France;Algobank-Caen, Université de Caen Basse-Normandie, Caen, France
Recommended Citation:
Pauline Bazin,Fabien Jouenne,Thomas Friedl,et al. Phytoplankton Diversity and Community Composition along the Estuarine Gradient of a Temperate Macrotidal Ecosystem: Combined Morphological and Molecular Approaches[J]. PLOS ONE,2014-01-01,9(4)