ALBERT

Description: Marine plankton support global biological and geochemical processes. Surveys of their biodiversity have hitherto been geographically restricted and have not accounted for the full range of plankton size. We assessed eukaryotic diversity from 334 size-fractionated photic-zone plankton communities collected across tropical and temperate oceans during the circumglobal Tara Oceans expedition. We analyzed 18S ribosomal DNA sequences across the intermediate plankton-size spectrum from the smallest unicellular eukaryotes (protists, 〉0.8 micrometers) to small animals of a few millimeters. Eukaryotic ribosomal diversity saturated at ~150,000 operational taxonomic units, about one-third of which could not be assigned to known eukaryotic groups. Diversity emerged at all taxonomic levels, both within the groups comprising the ~11,200 cataloged morphospecies of eukaryotic plankton and among twice as many other deep-branching lineages of unappreciated importance in plankton ecology studies. Most eukaryotic plankton biodiversity belonged to heterotrophic protistan groups, particularly those known to be parasites or symbiotic hosts.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉de Vargas, Colomban -- Audic, Stephane -- Henry, Nicolas -- Decelle, Johan -- Mahe, Frederic -- Logares, Ramiro -- Lara, Enrique -- Berney, Cedric -- Le Bescot, Noan -- Probert, Ian -- Carmichael, Margaux -- Poulain, Julie -- Romac, Sarah -- Colin, Sebastien -- Aury, Jean-Marc -- Bittner, Lucie -- Chaffron, Samuel -- Dunthorn, Micah -- Engelen, Stefan -- Flegontova, Olga -- Guidi, Lionel -- Horak, Ales -- Jaillon, Olivier -- Lima-Mendez, Gipsi -- Lukes, Julius -- Malviya, Shruti -- Morard, Raphael -- Mulot, Matthieu -- Scalco, Eleonora -- Siano, Raffaele -- Vincent, Flora -- Zingone, Adriana -- Dimier, Celine -- Picheral, Marc -- Searson, Sarah -- Kandels-Lewis, Stefanie -- Tara Oceans Coordinators -- Acinas, Silvia G -- Bork, Peer -- Bowler, Chris -- Gorsky, Gabriel -- Grimsley, Nigel -- Hingamp, Pascal -- Iudicone, Daniele -- Not, Fabrice -- Ogata, Hiroyuki -- Pesant, Stephane -- Raes, Jeroen -- Sieracki, Michael E -- Speich, Sabrina -- Stemmann, Lars -- Sunagawa, Shinichi -- Weissenbach, Jean -- Wincker, Patrick -- Karsenti, Eric -- New York, N.Y. -- Science. 2015 May 22;348(6237):1261605. doi: 10.1126/science.1261605.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉CNRS, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. Sorbonne Universites, Universite Pierre et Marie Curie (UPMC) Paris 06, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. vargas@sb-roscoff.fr pwincker@genoscope.cns.fr karsenti@embl.de. ; CNRS, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. Sorbonne Universites, Universite Pierre et Marie Curie (UPMC) Paris 06, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. ; Department of Ecology, University of Kaiserslautern, Erwin-Schroedinger Street, 67663 Kaiserslautern, Germany. CNRS, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. Sorbonne Universites, Universite Pierre et Marie Curie (UPMC) Paris 06, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. ; Department of Marine Biology and Oceanography, Institute of Marine Science (ICM)-Consejo Superior de Investigaciones Cientificas (CSIC), Passeig Maritim de la Barceloneta 37-49, Barcelona E08003, Spain. ; Laboratory of Soil Biology, University of Neuchatel, Rue Emile-Argand 11, 2000 Neuchatel, Switzerland. ; CNRS, FR2424, Roscoff Culture Collection, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. Sorbonne Universites, UPMC Paris 06, FR 2424, Roscoff Culture Collection, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. ; CNRS, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. Sorbonne Universites, Universite Pierre et Marie Curie (UPMC) Paris 06, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. Ecole Normale Superieure, Institut de Biologie de l'ENS (IBENS), and Inserm U1024, and CNRS UMR 8197, Paris, F-75005 France. ; Commissariat a l'Energie Atomique et aux Energies Alternatives (CEA), Institut de Genomique, GENOSCOPE, 2 rue Gaston Cremieux, 91000 Evry, France. ; CNRS FR3631, Institut de Biologie Paris-Seine, F-75005, Paris, France. Sorbonne Universites, UPMC Paris 06, Institut de Biologie Paris-Seine, F-75005, Paris, France. Ecole Normale Superieure, Institut de Biologie de l'ENS (IBENS), and Inserm U1024, and CNRS UMR 8197, Paris, F-75005 France. CNRS, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. Sorbonne Universites, Universite Pierre et Marie Curie (UPMC) Paris 06, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. ; Department of Microbiology and Immunology, Rega Institute, KU Leuven, Herestraat 49, 3000 Leuven, Belgium. Center for the Biology of Disease, VIB, Herestraat 49, 3000 Leuven, Belgium. Department of Applied Biological Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium. ; Department of Ecology, University of Kaiserslautern, Erwin-Schroedinger Street, 67663 Kaiserslautern, Germany. ; Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branisovska 31, 37005 Ceske Budejovice, Czech Republic. Faculty of Science, University of South Bohemia, Branisovska 31, 37005 Ceske Budejovice, Czech Republic. ; CNRS, UMR 7093, Laboratoire d'Oceanographie de Villefranche-sur-Mer (LOV), Observatoire Oceanologique, F-06230, Villefranche-sur-Mer, France. Sorbonne Universites, UPMC Paris 06, UMR 7093, LOV, Observatoire Oceanologique, F-06230, Villefranche-sur-Mer, France. ; Commissariat a l'Energie Atomique et aux Energies Alternatives (CEA), Institut de Genomique, GENOSCOPE, 2 rue Gaston Cremieux, 91000 Evry, France. CNRS, UMR 8030, CP5706, Evry, France. Universite d'Evry, UMR 8030, CP5706, Evry, France. ; Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branisovska 31, 37005 Ceske Budejovice, Czech Republic. Faculty of Science, University of South Bohemia, Branisovska 31, 37005 Ceske Budejovice, Czech Republic. Canadian Institute for Advanced Research, 180 Dundas Street West, Suite 1400, Toronto, Ontario M5G 1Z8, Canada. ; Ecole Normale Superieure, Institut de Biologie de l'ENS (IBENS), and Inserm U1024, and CNRS UMR 8197, Paris, F-75005 France. ; MARUM, Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany. CNRS, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. Sorbonne Universites, Universite Pierre et Marie Curie (UPMC) Paris 06, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. ; Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy. ; Ifremer, Centre de Brest, DYNECO/Pelagos CS 10070, 29280 Plouzane, France. ; Center for the Biology of Disease, VIB, Herestraat 49, 3000 Leuven, Belgium. Ecole Normale Superieure, Institut de Biologie de l'ENS (IBENS), and Inserm U1024, and CNRS UMR 8197, Paris, F-75005 France. ; Structural and Computational Biology, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany. Directors' Research, EMBL, Meyerhofstrasse 1, 69117 Heidelberg, Germany. ; Structural and Computational Biology, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany. Max-Delbruck-Centre for Molecular Medicine, 13092 Berlin, Germany. ; CNRS UMR 7232, Biologie Integrative des Organismes Marins (BIOM), Avenue du Fontaule, 66650 Banyuls-sur-Mer, France. Sorbonne Universites Paris 06, Observatoire Oceanologique de Banyuls (OOB) UPMC, Avenue du Fontaule, 66650 Banyuls-sur-Mer, France. ; Aix Marseille Universite, CNRS IGS UMR 7256, 13288 Marseille, France. ; Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan. ; PANGAEA, Data Publisher for Earth and Environmental Science, University of Bremen, Bremen, Germany. MARUM, Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany. ; Bigelow Laboratory for Ocean Sciences, East Boothbay, ME 04544, USA. National Science Foundation, Arlington, VA 22230, USA. ; Department of Geosciences, Laboratoire de Meteorologie Dynamique (LMD), Ecole Normale Superieure, 24 rue Lhomond, 75231 Paris Cedex 05, France. Laboratoire de Physique des Oceans, Universite de Bretagne Occidentale (UBO)-Institut Universitaire Europeen de la Mer (IUEM), Place Copernic, 29820 Plouzane, France. ; Structural and Computational Biology, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany. ; Commissariat a l'Energie Atomique et aux Energies Alternatives (CEA), Institut de Genomique, GENOSCOPE, 2 rue Gaston Cremieux, 91000 Evry, France. CNRS, UMR 8030, CP5706, Evry, France. Universite d'Evry, UMR 8030, CP5706, Evry, France. vargas@sb-roscoff.fr pwincker@genoscope.cns.fr karsenti@embl.de. ; Directors' Research, EMBL, Meyerhofstrasse 1, 69117 Heidelberg, Germany. Ecole Normale Superieure, Institut de Biologie de l'ENS (IBENS), and Inserm U1024, and CNRS UMR 8197, Paris, F-75005 France. vargas@sb-roscoff.fr pwincker@genoscope.cns.fr karsenti@embl.de.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25999516" target="_blank"〉PubMed〈/a〉

Description: Marine protist diversity inventories have largely focused on planktonic environments, while benthic protists have received relatively little attention. We therefore hypothesize that current diversity surveys have only skimmed the surface of protist diversity in marine sediments, which may harbor greater diversity than planktonic environments. We tested this by analyzing sequences of the hypervariable V4 18S rRNA from benthic and planktonic protist communities sampled in European coastal regions. Despite a similar number of OTUs in both realms, richness estimations indicated that we recovered at least 70% of the diversity in planktonic protist communities, but only 33% in benthic communities. There was also little overlap of OTUs between planktonic and benthic communities, as well as between separate benthic communities. We argue that these patterns reflect the heterogeneity and diversity of benthic habitats. A comparison of all OTUs against the Protist Ribosomal Reference database showed that a higher proportion of benthic than planktonic protist diversity is missing from public databases; similar results were obtained by comparing all OTUs against environmental references from NCBI's Short Read Archive. We suggest that the benthic realm may therefore be the world's largest reservoir of marine protist diversity, with most taxa at present undescribed.

Description: Recent culture-independent studies of marine planktonic protists have unveiled a large diversity at all phylogenetic scales and the existence of novel groups. MAST-4 represents one of these novel uncultured lineages, and it is composed of small (~2 μm) bacterivorous eukaryotes that are widely distributed in marine systems. MAST-4 accounts for a significant fraction of the marine heterotrophic flagellates at the global level, playing key roles in the marine ecological network. In this study, we investigated the diversity of MAST-4, aiming to assess its limits and structure. Using ribosomal DNA (rDNA) sequences obtained in this study (both pyrosequencing reads and clones with large rDNA operon coverage), complemented with GenBank sequences, we show that MAST-4 is composed of only five main clades, which are well supported by small subunit and large subunit phylogenies. The differences in the conserved regions of the internal transcribed spacers 1 and 2 (ITS1 and ITS2) secondary structures strongly suggest that these five clades are different biological species. Based on intraclade divergence, ITS secondary structures and comparisons of ITS1 and ITS2 trees, we did not find evidence of more than one species within clade A, whereas as many as three species might be present within other clades. Overall, the genetic divergence of MAST-4 was surprisingly low for an organism with a global population size estimated to be around 10 24 , indicating a very low evolutionary diversification within the group.

Description: Nucleotide positions in the hypervariable V4 and V9 regions of the small subunit (SSU)-rDNA locus are normally difficult to align and are usually removed before standard phylogenetic analyses. Yet, with next-generation sequencing data, amplicons of these regions are all that are available to answer ecological and evolutionary questions that rely on phylogenetic inferences. With ciliates, we asked how inclusion of the V4 or V9 regions, regardless of alignment quality, affects tree topologies using distinct phylogenetic methods (including PairDist that is introduced here). Results show that the best approach is to place V4 amplicons into an alignment of full-length Sanger SSU-rDNA sequences and to infer the phylogenetic tree with RAxML. A sliding window algorithm as implemented in RAxML shows, though, that not all nucleotide positions in the V4 region are better than V9 at inferring the ciliate tree. With this approach and an ancestral-state reconstruction, we use V4 amplicons from European nearshore sampling sites to infer that rather than being primarily terrestrial and freshwater, colpodean ciliates may have repeatedly transitioned from terrestrial/freshwater to marine environments.

Description: Marine aerosols play a significant role in the global radiative budget, in clouds’ processes, and in the chemistry of the marine atmosphere. There is a critical need to better understand their production mechanisms, composition, chemical properties, and the contribution of ocean-derived biogenic matter to their mass and number concentration. Here we present an overview of a new dataset of in situ measurements of marine aerosols conducted over the 2.5-yr Tara Pacific Expedition over 110,000 km across the Atlantic and Pacific Oceans. Preliminary results are presented here to describe the new dataset that will be built using this novel set of measurements. It will characterize marine aerosols properties in detail and will open a new window to study the marine aerosol link to the water properties and environmental conditions.

Description: The increase in atmospheric carbon dioxide (CO2) results in acidification of the oceans, expected to lead to the fastest drop in ocean pH in the last 300 million years, if anthropogenic emissions are continued at present rate. Due to higher solubility of gases in cold waters and increased exposure to the atmosphere by decreasing ice cover, the Arctic Ocean will be among the areas most strongly affected by ocean acidification. Yet, the response of the plankton community of high latitudes to ocean acidification has not been studied so far. This work is part of the Arctic campaign of the European Project on Ocean Acidification (EPOCA) in 2010, employing 9 in situ mesocosms of about 45 000 l each to simulate ocean acidification in Kongsfjorden, Svalbard (78°56.2' N 11°53.6' E). In the present study, we investigated effects of elevated CO2 on the composition and richness of particle attached (PA; 〉3 μm) and free living (FL; 0.2 μm) bacterial communities by Automated Ribosomal Intergenic Spacer Analysis (ARISA) in 6 of the mesocosms and the surrounding fjord, ranging from 185 to 1050 initial μatm pCO2. ARISA was able to resolve about 20–30 bacterial band-classes per sample and allowed for a detailed investigation of the explicit richness. Both, the PA and the FL bacterioplankton community exhibited a strong temporal development, which was driven mainly by temperature and phytoplankton development. In response to the breakdown of a picophytoplankton bloom (phase 3 of the experiment), number of ARISA-band classes in the PA-community were reduced at low and medium CO2 (∼180–600 μatm) by about 25%, while it was more or less stable at high CO2 (∼ 650–800 μatm). We hypothesise that enhanced viral lysis and enhanced availability of organic substrates at high CO2 resulted in a more diverse PA-bacterial community in the post-bloom phase. Despite lower cell numbers and extracellular enzyme activities in the post-bloom phase, bacterial protein production was enhanced in high CO2-treatments, suggesting a positive effect of community richness on this function and on carbon cycling by bacteria.

Description: The impact of ocean acidification and carbonation on microbial community structure was assessed during a large-scale in situ costal pelagic mesocosm study, included as part of the EPOCA 2010 Arctic campaign. The mesocosm experiment included ambient conditions (fjord) and nine mesocosms, with pCO2 range from ~145 to ~1420 μatm. Samples collected at nine time points (t-1, t1, t5, t7, t12, t14, t22, t26 to t28) in seven treatments (ambient fjord (~145), 2×~185, ~270, ~685, ~820, ~1050 μatm) were analysed for "free-living" and "particle associated" microbial community composition using 16S rRNA amplicon sequencing. This high-throughput sequencing analysis produced ~20 000 000 16S rRNA V4 reads, which comprised 7000 OTUs. The main variables structuring these communities were, sample origin (fjord or mesocosms) and the filter size fraction (free-living or particle associated). The community was significantly different between the fjord and both the control and elevated 2 mesocosms (which were not significant different) after nutrients were added to the mesocosms; suggesting that the addition of nutrients is the primary driver of the change in mesocosm community structure. The relative importance of each structuring variable depended greatly on the time at which the community was sampled in relation to the phytoplankton bloom. The size fraction was the second most important factor for community structure; separating free-living from particle-associated bacteria. When free-living and particle-associated bacteria were analysed separately at different time points, the only taxon pCO2 was found to significantly affect were the Gammaproteobacteria after nutrient addition. Finally, pCO2 treatment was found to be significantly correlated (non-linear) with 15 rare taxa, most of which increased in abundance with higher CO2.

Description: The impact of ocean acidification and carbonation on microbial community structure was assessed during a large-scale in situ costal pelagic mesocosm study, included as part of the EPOCA 2010 Arctic campaign. The mesocosm experiment included ambient conditions (fjord) and nine mesocosms with pCO2 levels ranging from ~145 to ~1420 μatm. Samples for the present study were collected at ten time points (t–1, t1, t5, t7, t12, t14, t18, t22, t26 to t28) in seven treatments (ambient fjord (~145), 2 × ~185, ~270, ~685, ~820, ~1050 μatm) and were analysed for "small" and "large" size fraction microbial community composition using 16S RNA (ribosomal ribonucleic acid) amplicon sequencing. This high-throughput sequencing analysis produced ~20 000 000 16S rRNA V4 reads, which comprised 7000 OTUs. The main variables structuring these communities were sample origins (fjord or mesocosms) and the community size fraction (small or large size fraction). The community was significantly different between the unenclosed fjord water and enclosed mesocosms (both control and elevated CO2 treatments) after nutrients were added to the mesocosms, suggesting that the addition of nutrients is the primary driver of the change in mesocosm community structure. The relative importance of each structuring variable depended greatly on the time at which the community was sampled in relation to the phytoplankton bloom. The sampling strategy of separating the small and large size fraction was the second most important factor for community structure. When the small and large size fraction bacteria were analysed separately at different time points, the only taxon pCO2 was found to significantly affect were the Gammaproteobacteria after nutrient addition. Finally, pCO2 treatment was found to be significantly correlated (non-linear) with 15 rare taxa, most of which increased in abundance with higher CO2.

Description: In the frame of the European Project on Ocean Acidification (EPOCA), the response of an Arctic pelagic community (3 μm) and free-living (FL; 〈 3 μm 〉 0.2 μm) bacteria by Automated Ribosomal Intergenic Spacer Analysis (ARISA) in 6 of the mesocosms, ranging from 185 to 1050 μatm initial pCO2, and the surrounding fjord. ARISA was able to resolve, on average, 27 bacterial band classes per sample and allowed for a detailed investigation of the explicit richness and diversity. Both, the PA and the FL bacterioplankton community exhibited a strong temporal development, which was driven mainly by temperature and phytoplankton development. In response to the breakdown of a picophytoplankton bloom, numbers of ARISA band classes in the PA community were reduced at low and medium CO2 (~ 185–685 μatm) by about 25%, while they were more or less stable at high CO2 (~ 820–1050 μatm). We hypothesise that enhanced viral lysis and enhanced availability of organic substrates at high CO2 resulted in a more diverse PA bacterial community in the post-bloom phase. Despite lower cell numbers and extracellular enzyme activities in the post-bloom phase, bacterial protein production was enhanced in high CO2 mesocosms, suggesting a positive effect of community richness on this function and on carbon cycling by bacteria.