Environmental Barcoding Reveals Massive Dinoflagellate Diversity in Marine Environments

Rowena F. Stern is with University of British Columbia, Ales Horak is with University of British Columbia, Rose L. Andrew is with University of British Columbia, Mary-Alice Coffroth is with State University of New York at Buffalo, Robert A. Andersen is with the Bigelow Laboratory for Ocean Sciences, Frithjof C. Küpper is with the Scottish Marine Institute, Ian Jameson is with CSIRO Marine and Atmospheric Research, Mona Hoppenrath is with the German Center for Marine Biodiversity Research, Benoît Véron is with University of Caen Lower Normandy and the National Institute for Environmental Studies, Fumai Kasai is with the National Institute for Environmental Studies, Jerry Brand is with UT Austin, Erick R. James is with University of British Columbia, Patrick J. Keeling is with University of British Columbia.Background -- Dinoflagellates are an ecologically important group of protists with important functions as primary producers, coral symbionts and in toxic red tides. Although widely studied, the natural diversity of dinoflagellates is not well known. DNA barcoding has been utilized successfully for many protist groups. We used this approach to systematically sample known “species”, as a reference to measure the natural diversity in three marine environments. Methodology/Principal Findings -- In this study, we assembled a large cytochrome c oxidase 1 (COI) barcode database from 8 public algal culture collections plus 3 private collections worldwide resulting in 336 individual barcodes linked to specific cultures. We demonstrate that COI can identify to the species level in 15 dinoflagellate genera, generally in agreement with existing species names. Exceptions were found in species belonging to genera that were generally already known to be taxonomically challenging, such as Alexandrium or Symbiodinium. Using this barcode database as a baseline for cultured dinoflagellate diversity, we investigated the natural diversity in three diverse marine environments (Northeast Pacific, Northwest Atlantic, and Caribbean), including an evaluation of single-cell barcoding to identify uncultivated groups. From all three environments, the great majority of barcodes were not represented by any known cultured dinoflagellate, and we also observed an explosion in the diversity of genera that previously contained a modest number of known species, belonging to Kareniaceae. In total, 91.5% of non-identical environmental barcodes represent distinct species, but only 51 out of 603 unique environmental barcodes could be linked to cultured species using a conservative cut-off based on distances between cultured species. Conclusions/Significance -- COI barcoding was successful in identifying species from 70% of cultured genera. When applied to environmental samples, it revealed a massive amount of natural diversity in dinoflagellates. This highlights the extent to which we underestimate microbial diversity in the environment.This project was funded by Genome Canada and the Canadian Barcode of Life Network. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Biological Sciences, School o

New species of Pavlovophyceae (Haptophyta) and revision of the genera Exanthemachrysis, Rebecca and Pavlova

International audienceThe justification of the 4 genera that currently compose the class Pavlovophyceae is based on a low number of species and a relative paucity of available, traceable and referenced cultures. Previous integrative phylogeny work revealed strains that can refine and strengthen our knowledge of the genera in the class. The application of multiple light and electron microscopy techniques allowed us to prioritize the cytomorphological characters (pyrenoid, thylakoid, stigma, knob-scales, life stage / life cycle) used for the taxonomy of these algae and to describe two new species: Exanthemachrysis fresneliae Véron sp. nov. and Rebecca billardiae Véron sp. nov. Consequently, revisions of the two genera Exanthemachrysis Lepailleur emend. Véron and Rebecca Green emend. Véron were made. In addition, the genus Pavlova Butcher emend Véron is revised in the light of these characters. Particular emphasis is placed on the life stages and habitat of the species

New species of Pavlovophyceae (Haptophyta) and revision of the genera Exanthemachrysis, Rebecca and Pavlova

International audienceThe justification of the 4 genera that currently compose the class Pavlovophyceae is based on a low number of species and a relative paucity of available, traceable and referenced cultures. Previous integrative phylogeny work revealed strains that can refine and strengthen our knowledge of the genera in the class. The application of multiple light and electron microscopy techniques allowed us to prioritize the cytomorphological characters (pyrenoid, thylakoid, stigma, knob-scales, life stage / life cycle) used for the taxonomy of these algae and to describe two new species: Exanthemachrysis fresneliae Véron sp. nov. and Rebecca billardiae Véron sp. nov. Consequently, revisions of the two genera Exanthemachrysis Lepailleur emend. Véron and Rebecca Green emend. Véron were made. In addition, the genus Pavlova Butcher emend Véron is revised in the light of these characters. Particular emphasis is placed on the life stages and habitat of the species

Les évolutions de la reconnaissance des (in)capacités juridiques : une comparaison France-Québec

International audienceLes travaux comparatifs sur les enjeux de santé et de protection sociale ont développé des modèles concernant l’organisation sociopolitique de l’État social, prenant en compte notamment le coût des prises en charge des personnes vulnérables. Peu se sont en revanche intéressés à la place des droits civils et politiques dans la comparaison.Au-delà de l’augmentation du nombre de mesures de contraintes légales dans de nombreux pays occidentaux, la reconnaissance des (in)capacités juridiques soulève la question des répercussions que peuvent produire des situations de handicap, de dépendance ou de maladie sur l’exercice par les personnes vulnérables de leurs droits. Elle révèle plus largement les tensions concrètes produites par la coexistence d’idéaux difficiles à articuler, comme ceux d’autonomie et de protection ou de solidarité et de liberté.Cet article entend comparer de manière sociohistorique l’évolution des modes de reconnaissance des (in)capacités juridiques en France et au Québec. Il éclaire la place prise par des acteurs et savoirs « experts » dans l’évaluation clinique des (in)capacités ainsi que celle d’experts internationaux des droits humains en dégageant les éléments saillants de trois modes de reconnaissance des (in)capacités. Il met en perspective les articulations et tensions contemporaines entre le souci clinique pour les personnes vulnérabilisées et celui du respect de leurs droits

Dynamics of Pseudo-nitzschia spp. and domoic acid production in a macrotidal ecosystem of the Eastern English Channel (Normandy, France)

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Cryopreservation of the coccolithophore, Emiliania huxleyi (Haptophyta, Prymnesiophyceae)

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Complex patterns in phytoplankton and microeukaryote diversity along the estuarine continuum

International audienceEstuaries and coastal lagoons are included within the transitional waters category, according to the Water Framework Directive. However, criteria for their differentiation and characterisation are still under discussion and require more research. In particular, detailed observations of biodiversity in more complex transitional and coastal waters are lacking. Microscopic and molecular analyses were therefore used to investigate phytoplankton diversity and spatial community structure, in early spring, along the freshwater-to-marine continuum of the Segura River (Spain), an intensively regulated semiarid basin discharging into the Mediterranean Sea. In addition to the salinity gradient as the major factor determining taxa distribution, influence of multiple anthropogenic and climatic impacting factors (drought, confined waters, irrigation canal) leads to a significant spatial heterogeneity of the aquatic habitat types associated with variations in community composition. Several shifts within the phytoplankton distribution pattern along the continuum are revealed using multivariate analyses. An impressive bloom of the cryptophyte Plagioselmis prolonga occurred in the mixing zone, associated with a typical euryhaline community indicative of eutrophication. The 18S rDNA diversity revealed a microeukaryotic richness including several little-known groups, heterotrophic representatives, and potential parasites. By combining morphological and molecular approaches we revealed the presence of a ‘hidden’ diversity often neglected in traditional surveys

Phytoplankton Diversity and Community Composition along the Estuarine Gradient of a Temperate Macrotidal Ecosystem: Combined Morphological and Molecular Approaches

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Contamination and depuration of Paralytic Shellfish Poisoning by Acanthocardia tuberculata cockles and Callista chione clams in Moroccan waters

International audienceThis study of Gymnodinium catenatum was conducted across two sampling stations; M'diq bay and Oued Laou estuary during the period from July 2007 to May 2009. Gymnodinium catenatum blooms occurred after a rainfall event in autumn and early winter. Statically analyses showed a positive correlation with rainfall. During January 2008, the G. catenatum bloom resulted in contamination of tuberculate cockles and sweet clam by Paralytic Shellfish Poisoning (PSP) toxins. In the Oued Laou estuary, the levels of these toxins in shellfish went beyond the normative threshold for consumption of shellfish, (80 µg SXTeq. /100g of meat) and reached (710 ± 82.07) and (198 ± 6.56) µg SXTeq. /100g of meat in cockles and sweet clam respectively. In M'diq bay, concentrations of PSP toxins in the meat of these two shellfish were lower (256.57 ± 12.22 µg SXTeq. /100g and 80.66 ± 8.14 µg SXTeq. /100g of meat in tuberculate cockles and sweet clam respectively. An experimental test of depuration of tuberculate cockles and sweet clam contaminated by the PSP toxins was conducted in laboratory conditions in the first week of January 2008. The results showed partial and progressive elimination of PSP toxins in two shellfish species over time. In the tuberculate cockle, the elimination of PSP appears to be slower compared with the sweet clam; it took 120 days to reach levels of 80 µg SXTeq. /100g of meat, on the other hand only 3 days were needed to reach this safe concentration in the sweet clam