Author
Lars Stemmann
Other affiliations: Texas A&M University, Pierre-and-Marie-Curie University, Centre national de la recherche scientifique
Bio: Lars Stemmann is an academic researcher from University of Paris. The author has contributed to research in topics: Zooplankton & Plankton. The author has an hindex of 40, co-authored 100 publications receiving 8050 citations. Previous affiliations of Lars Stemmann include Texas A&M University & Pierre-and-Marie-Curie University.
Papers published on a yearly basis
Papers
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TL;DR: This work identifies ocean microbial core functionality and reveals that >73% of its abundance is shared with the human gut microbiome despite the physicochemical differences between these two ecosystems.
Abstract: Microbes are dominant drivers of biogeochemical processes, yet drawing a global picture of functional diversity, microbial community structure, and their ecological determinants remains a grand challenge. We analyzed 7.2 terabases of metagenomic data from 243 Tara Oceans samples from 68 locations in epipelagic and mesopelagic waters across the globe to generate an ocean microbial reference gene catalog with >40 million nonredundant, mostly novel sequences from viruses, prokaryotes, and picoeukaryotes. Using 139 prokaryote-enriched samples, containing >35,000 species, we show vertical stratification with epipelagic community composition mostly driven by temperature rather than other environmental factors or geography. We identify ocean microbial core functionality and reveal that >73% of its abundance is shared with the human gut microbiome despite the physicochemical differences between these two ecosystems.
1,934 citations
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Centre national de la recherche scientifique1, Pierre-and-Marie-Curie University2, Kaiserslautern University of Technology3, Spanish National Research Council4, École Normale Supérieure5, Commissariat à l'énergie atomique et aux énergies alternatives6, Vrije Universiteit Brussel7, Katholieke Universiteit Leuven8, Sewanee: The University of the South9, Academy of Sciences of the Czech Republic10, University of Évry Val d'Essonne11, Canadian Institute for Advanced Research12, University of Bremen13, Stazione Zoologica Anton Dohrn14, IFREMER15, European Bioinformatics Institute16, Kyoto University17, Max Delbrück Center for Molecular Medicine18, University of Paris19, Aix-Marseille University20, National Science Foundation21, Bigelow Laboratory For Ocean Sciences22, University of Western Brittany23
TL;DR: 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.
Abstract: 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.
1,378 citations
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Vrije Universiteit Brussel1, Pierre-and-Marie-Curie University2, Université libre de Bruxelles3, University of Arizona4, École Normale Supérieure5, Université catholique de Louvain6, Katholieke Universiteit Leuven7, Spanish National Research Council8, University of Paris9, University of Bremen10, Centre national de la recherche scientifique11, Kyoto University12, University of Western Brittany13, French Alternative Energies and Atomic Energy Commission14
TL;DR: It is found that environmental factors are incomplete predictors of community structure and associations across plankton functional types and phylogenetic groups to be nonrandomly distributed on the network and driven by both local and global patterns.
Abstract: Species interaction networks are shaped by abiotic and biotic factors. Here, as part of the Tara Oceans project, we studied the photic zone interactome using environmental factors and organismal abundance profiles and found that environmental factors are incomplete predictors of community structure. We found associations across plankton functional types and phylogenetic groups to be nonrandomly distributed on the network and driven by both local and global patterns. We identified interactions among grazers, primary producers, viruses, and (mainly parasitic) symbionts and validated network-generated hypotheses using microscopy to confirm symbiotic relationships. We have thus provided a resource to support further research on ocean food webs and integrating biological components into ocean models.
717 citations
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TL;DR: It is shown that specific plankton communities, from the surface and deep chlorophyll maximum, correlate with carbon export at 150 m and that the relative abundance of a few bacterial and viral genes can predict a significant fraction of the variability in carbon export in these regions.
Abstract: The biological carbon pump is the process by which CO2 is transformed to organic carbon via photosynthesis, exported through sinking particles, and finally sequestered in the deep ocean. While the intensity of the pump correlates with plankton community composition, the underlying ecosystem structure driving the process remains largely uncharacterized. Here we use environmental and metagenomic data gathered during the Tara Oceans expedition to improve our understanding of carbon export in the oligotrophic ocean. We show that specific plankton communities, from the surface and deep chlorophyll maximum, correlate with carbon export at 150 m and highlight unexpected taxa such as Radiolaria and alveolate parasites, as well as Synechococcus and their phages, as lineages most strongly associated with carbon export in the subtropical, nutrient-depleted, oligotrophic ocean. Additionally, we show that the relative abundance of a few bacterial and viral genes can predict a significant fraction of the variability in carbon export in these regions.
556 citations
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Ohio State University1, Rega Institute for Medical Research2, University of Exeter3, Université Paris-Saclay4, University of Paris5, Utrecht University6, École Normale Supérieure7, Laval University8, University of Bremen9, Shirshov Institute of Oceanology10, University of Maine11, Wellcome Trust12, Massachusetts Institute of Technology13, Stazione Zoologica Anton Dohrn14, Bigelow Laboratory For Ocean Sciences15, Université catholique de Louvain16, University of Arizona17, Swiss Institute of Bioinformatics18, Radboud University Nijmegen19
TL;DR: An ∼12-fold expanded global ocean DNA virome dataset is established of 195,728 viral populations, now including the Arctic Ocean, and it is validated that these populations form discrete genotypic clusters.
441 citations
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01 Jun 2012
TL;DR: SPAdes as mentioned in this paper is a new assembler for both single-cell and standard (multicell) assembly, and demonstrate that it improves on the recently released E+V-SC assembler and on popular assemblers Velvet and SoapDeNovo (for multicell data).
Abstract: The lion's share of bacteria in various environments cannot be cloned in the laboratory and thus cannot be sequenced using existing technologies. A major goal of single-cell genomics is to complement gene-centric metagenomic data with whole-genome assemblies of uncultivated organisms. Assembly of single-cell data is challenging because of highly non-uniform read coverage as well as elevated levels of sequencing errors and chimeric reads. We describe SPAdes, a new assembler for both single-cell and standard (multicell) assembly, and demonstrate that it improves on the recently released E+V-SC assembler (specialized for single-cell data) and on popular assemblers Velvet and SoapDeNovo (for multicell data). SPAdes generates single-cell assemblies, providing information about genomes of uncultivatable bacteria that vastly exceeds what may be obtained via traditional metagenomics studies. SPAdes is available online ( http://bioinf.spbau.ru/spades ). It is distributed as open source software.
10,124 citations
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2,261 citations
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TL;DR: In marine ecosystems, rising atmospheric CO2 and climate change are associated with concurrent shifts in temperature, circulation, stratification, nutrient input, oxygen content, and ocean acidification, with potentially wide-ranging biological effects.
Abstract: In marine ecosystems, rising atmospheric CO2 and climate change are associated with concurrent shifts in temperature, circulation, stratification, nutrient input, oxygen content, and ocean acidification, with potentially wideranging biological effects. Population-level shifts are occurring because of physiological intolerance to new environments, altered dispersal patterns, and changes in species interactions. Together with local climate-driven invasion and extinction, these processes result in altered community structure and diversity, including possible emergence of novel ecosystems. Impacts are particularly striking for the poles and the tropics, because of the sensitivity of polar ecosystems to sea-ice retreat and poleward species migrations as well as the sensitivity of coral-algal symbiosis to minor increases in temperature. Midlatitude upwelling systems, like the California Current, exhibit strong linkages between climate and species distributions, phenology, and demography. Aggregated effects may modify energy and material flows as well as biogeochemical cycles, eventually impacting the overall ecosystem functioning and services upon which people and societies depend.
2,136 citations
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TL;DR: The K EGG pathway maps are now integrated with network variation maps in the NETWORK database, as well as with conserved functional units of KEGG modules and reaction modules in the MODULE database, and the KO database for functional orthologs continues to be improved.
Abstract: KEGG (https://www.kegg.jp/) is a manually curated resource integrating eighteen databases categorized into systems, genomic, chemical and health information. It also provides KEGG mapping tools, which enable understanding of cellular and organism-level functions from genome sequences and other molecular datasets. KEGG mapping is a predictive method of reconstructing molecular network systems from molecular building blocks based on the concept of functional orthologs. Since the introduction of the KEGG NETWORK database, various diseases have been associated with network variants, which are perturbed molecular networks caused by human gene variants, viruses, other pathogens and environmental factors. The network variation maps are created as aligned sets of related networks showing, for example, how different viruses inhibit or activate specific cellular signaling pathways. The KEGG pathway maps are now integrated with network variation maps in the NETWORK database, as well as with conserved functional units of KEGG modules and reaction modules in the MODULE database. The KO database for functional orthologs continues to be improved and virus KOs are being expanded for better understanding of virus-cell interactions and for enabling prediction of viral perturbations.
2,087 citations