Christian Jeanthon

Christian Jeanthon
Station Biologique de Roscoff · Adaptation et Diversité en Milieu Marin - UMR 7144 CNRS UPMC

PhD Biological Oceanography

About

440
Publications
29,334
Reads
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6,080
Citations
Citations since 2017
33 Research Items
1830 Citations
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2017201820192020202120222023050100150200250300
2017201820192020202120222023050100150200250300
Introduction
1987-91: PhD in Biological Oceanography (University of Western Brittany) 1991-92: Postdoctoral fellow at the Center for Nuclear Studies (Mol, Belgium) 1992-99: Research scientist (CNRS), Station Biologique, Roscoff 2000-02: Research scientist (CNRS), European Institute of Marine Studies, Plouzané 2002-05: Senior scientist (CNRS), European Institute of Marine Studies, Plouzané 2005-present: Senior scientist (CNRS), Station Biologique, Roscoff
Additional affiliations
September 2005 - present
Station Biologique de Roscoff
Position
  • Senior scientist (CNRS)
October 2002 - September 2005
European Institute of Marine Studies
Position
  • Senior scientist (CNRS)
June 2000 - October 2002
European Institute of Marine Studies
Position
  • Research scientist (CNRS)

Publications

Publications (440)
Article
Full-text available
Coccolithophores have global ecological and biogeochemical significance as the most important calcifying marine phytoplankton group. The structure and selection of prokaryotic communities associated with the most abundant coccolithophore and bloom‐forming species, Emiliania huxleyi, are still poorly known. In this study, we assessed the diversity o...
Preprint
Full-text available
Coccolithophores have global ecological and biogeochemical significance as the most important calcifying marine phytoplankton group. The structure and selection of prokaryotic communities associated with the most abundant coccolithophore and bloom-forming species, Emiliania huxleyi, are still poorly known. In this study, we assessed the diversity o...
Preprint
Coccolithophores have global ecological and biogeochemical significance as the most important calcifying marine phytoplankton group. The structure and selection of prokaryotic communities associated with the most abundant coccolithophore and bloom-forming species, Emiliania huxleyi, are still poorly known. In this study, we assessed the diversity o...
Article
Full-text available
The MALINA oceanographic campaign was conducted during summer 2009 to investigate the carbon stocks and the processes controlling the carbon fluxes in the Mackenzie River estuary and the Beaufort Sea. During the campaign, an extensive suite of physical, chemical and biological variables were measured across seven shelf–basin transects (south–north)...
Article
Full-text available
Anoxygenic phototrophic bacteria (APB) are a very significant metabolic functional group in the phytotelmata of tank‐forming Bromeliaceae plants. Considering the close relationships existing between the bromeliad and its tank microbiota, the dominance of APB raises the question of their role in the ecology and evolution of these plants. Here, by us...
Article
Full-text available
The MALINA oceanographic campaign was conducted during summer 2009 to investigate the carbon stocks and the processes controlling the carbon Fluxes in the Mackenzie River estuary and the Beaufort Sea. During the campaign, an extensive suite of physical, chemical and biological variables was measured across seven shelf–basin transects (south-north)...
Article
Full-text available
As critical primary producers and recyclers of organic matter, the diversity of marine protists has been extensively explored by high-throughput barcode sequencing. However, classification of short metabarcoding sequences into traditional taxonomic units is not trivial, especially for lineages mainly known by their genetic fingerprints. This is the...
Article
Full-text available
Silicimonas algicola strain KC90B T is an alphaproteobacterium of the Roseobacter clade that was isolated from a culture of the marine diatom Thalassiosira delicatula . Here, we report the complete genome sequence of this type strain, which is 4,351,658 bp in size with 4,272 coding sequences and an average G+C content of 65.2%.
Article
Full-text available
We report for the first time the in situ dynamics of a vampyrellid in a marine system. A high sampling frequency (twice-weekly) was applied in a tropical eutrophic lagoon (Rio de Janeiro, Brazil) for 5 years (2012–2016). The vampyrellid Hyalodiscus sp. specifically fed on the diatom Chaetoceros minimus during a short time window (~3 months), althou...
Article
Full-text available
Interactions between phytoplankton and bacteria play a central role in mediating biogeochemical cycling and food web structure in the ocean. The cosmopolitan diatoms Thalassiosira and Chaetoceros often dominate phytoplankton communities in marine systems. Past studies of diatom-bacterial associations have employed community-level methods and cultur...
Data
Maximum-likelihood tree based on 16S rRNA gene sequences showing the position of bacterial epibionts isolated from C. danicus RCC 2565 and T. delicatula RCC 2560 (Table 4). Only bootstrap values (expressed as percentages of 1000 replications) of >80% are shown. Filled circles indicate that the corresponding nodes were also recovered using the neigh...
Data
Attached bacteria on diatom cultures during late exponential (5 days) and late stationary (19 days) growth phases.
Article
Full-text available
In marine environments, aerobic anoxygenic phototrophic (AAP) bacterial assemblages vary in space and along environmental gradients but the factors shaping their diversity and distribution at different taxonomic levels remain poorly identified. Using sets of sequences encoding the M sub-unit of the photosynthetic apparatus from different oceanic re...
Article
Full-text available
Coastal areas form the major habitat of brown macroalgae, photosynthetic multicellular eukaryotes that have great ecological value and industrial potential. Macroalgal growth, development, and physiology are influenced by the microbial community they accommodate. Studying the algal microbiome should thus increase our fundamental understanding of al...
Data
Number of bacterial isolates obtained per experimental treatment.
Data
Bacterial growth media recipes for LB, R2A, Zobell, PYG, EC-based, and LNHM.
Data
Antibiotics used to reduce the abundance of Halomonas sp.
Data
Number of cultivable bacterial strains found in metabarcoding experiments depending on sample origin and sequencing library.
Article
Full-text available
Mass blooms of purple sulfur bacteria growing seasonally on green stranded macroalgae have a major impact on the microbial composition and functionality of intertidal mats. To explore the active anoxygenic phototrophic community in purple bacterial mats from the Roscoff Aber Bay (Brittany, France), we conducted a combined approach including molecul...
Poster
Full-text available
Proteorhodopsins (PR) are prokaryotic retinal-binding transmembrane proteins that function as light-driven proton pumps. PRs are widespread and abundant in polar, temperate and tropical marine waters. However, seasonal dynamics and temporal patterns of PR gene expression have not been studied. The PR gene diversity was examined for a two-year perio...
Article
Full-text available
Proteorhodopsins (PR) are phylogenetically diverse and highly expressed proton pumps in marine bacterial communities. The phylogenetic diversity and in situ expression of the main PR groups in polar offshore , coastal and estuarine waters is poorly known and their abundance has not yet been reported. Here, we show that PR gene sequences of the sout...
Article
Full-text available
Parasites play a role in the control of transient algal blooms, but it is not known whether parasite-mediated selection results in coevolution of the host and the parasites over this short time span. We investigated the presence of coevolution between the toxic dinoflagellate Alexandrium minutum and two naturally occurring endoparasites during bloo...
Article
Full-text available
Parasites play a role in the control of transient algal blooms, but it is not known whether parasite-mediated selection results in coevolution of the host and the parasites over this short timespan. We investigated the presence of coevolution between the toxic dinoflagellate Alexandrium minutum and two naturally occurring endoparasites during bloom...
Data
Full-text available
1 2 Collection of ancillary data 3 High vertical resolution environmental data were collected between 0 and up to 80 m depth 4 using a conductivity-temperature-depth-oxygen profiler (CTDO, Seabird 911 plus) with a 5 rosette supporting 24 12 L Niskin bottles equipped with silicon rubber closures. Inorganic 6 nutrients (nitrate, nitrite, phosphate an...
Article
Full-text available
Importance: Aerobic anoxygenic phototrophic bacteria are a widespread functional group in the upper ocean, and their abundance could be up to 15% of total heterotrophic bacteria. To date, a great number of studies display their biogeographic distribution patterns in the ocean, however little is understood about the geographic isolation impact on g...
Article
Full-text available
A Gram-negative, aerobic, non-motile bacterium, designated strain KC90BT, was isolated from the surface of a cell of the marine diatom Thalassiosira delicatula. The bacterial cells were pleomorphic and formed very small beige colonies on marine agar. Optimal growth was obtained at 25°C, at pH 6.5-7.5 and in the presence of 1.5-2.0% (w/v) NaCl. Phyl...
Chapter
Full-text available
Photosymbiosis is a symbiotic relationship between two or more organisms, one of which is capable of photosynthesis. Like other forms of symbiosis, photosymbioses can involve the full spectrum of trophic interactions from mutualism through commensalism to parasitism. As in marine benthic environments (e.g., coral reef ecosystems), photosymbiotic as...
Article
The contribution of bacteriochlorophyll a (BChl a) to photosynthetically driven electron transport is generally low in aquatic and terrestrial systems. Here, we provide evidence that anoxygenic bacterial phototrophy is widespread and substantial in water retained by tank bromeliads of a primary rainforest in French Guiana. An analysis of the water...
Article
Full-text available
The aim of this paper was to study the effects of temperature and irradiance on the photodegradation state of killed phytoplankton cells. For this purpose, killed cells of the diatom Chaetoceros neogracilis RCC2022 were irradiated (PAR radiations) at 36 and 446 J. s(-1.) m(-2) (for a same cumulative dose of irradiation energy) and at two temperatur...
Chapter
De.sul.fu.ro.bac.te' ri.um. L. pref. de from; L. n. sulfur sulfur; Gr. neut. dim. n. bakterion a small rod; M.L. neut. n. Desulfurobacterium sulfur-reducing rod-shaped bacterium. Aquificae / Aquificae / Aquificales / Aquificaceae / Desulfurobacterium Rod-shaped cells, about 0.4–0.5 × 1–2 µm. The rods occur singly or in pairs during the logarithmic...
Article
Full-text available
Microbial rhodopsins are a diverse group of photoactive transmembrane proteins found in all three domains of life and in viruses. Today, microbial rhodopsin research is a flourishing research field in which new understandings of rhodopsin diversity, function and evolution are contributing to broader microbiological and molecular knowledge. Here, we...
Article
Full-text available
Despite an increasing number of studies over the last 15 years, aerobic anoxygenic photoheterotrophic (AAP) bacteria remain a puzzling functional group in terms of physiology, metabolism, and ecology. To contribute to a better knowledge of their environmental distribution, the present study aims at analyzing their diversity and structure at the bou...
Article
Full-text available
Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of the marine microbial biodiversity and function of the world’s oceans. It is a simultaneous global mega-sequencing campaign aiming to generate the largest standardized microbial data set in a singl...
Article
Full-text available
The co-authors of this paper hereby state their intention to work together to launch the Genomic Observatories Network (GOs Network) for which this document will serve as its Founding Charter. We define a Genomic Observatory as an ecosystem and/or site subject to long-term scientific research, including (but not limited to) the sustained study of g...
Article
Full-text available
Environmental 18S rRNA gene surveys of microbial eukaryotes have recently revealed the diversity of major parasitic agents in pelagic freshwater systems, consisting primarily of chytrid fungi. To date, only a few studies have reported the presence of chydrids in the marine environment and a limited number of marine chytrids have been properly ident...
Article
Full-text available
The Arctic Ocean is a unique marine environment with respect to seasonality of light, temperature, perennial ice cover and strong stratification. Other important distinctive features are the influence of extensive continental shelves and its interactions with Atlantic and Pacific water masses and freshwater from sea ice melt and rivers. These chara...
Article
Full-text available
There is a relative absence of studies dealing with mats of purple sulphur bacteria in the intertidal zone. These bacteria display an array of metabolic pathways that allow them to disperse and develop under a wide variety of conditions, making these mats important in terms of ecosystem processes and functions. Mass blooms of purple sulphur bacteri...
Poster
Full-text available
Heterotrophic bacteria are crucial components of marine food webs and have key roles in controlling carbon fluxes in the oceans. Aerobic anoxygenic phototrophic (AAP) bacteria and proteorhodopsin (PR)-containing bacteria can depart from a strictly heterotrophic lifestyle by obtaining energy through unconventional mechanisms that are linked to the p...
Article
Aerobic anoxygenic phototrophic (AAP) bacteria are found in a range of aquatic and terrestrial environments, potentially playing unique roles in biogeochemical cycles. Although known to occur in the Arctic Ocean, their ecology and the factors that govern their community structure and distribution in this extreme environment are poorly understood. H...
Article
The diversity and ecological roles of protists in marine plankton are still poorly known. In 2011, we made a substantial effort to isolate parasites into cultures during the course of blooms of the toxic microalga Alexandrium minutum (Dinophyceae) in two estuaries (the Penzé and the Rance, Brittany coast, north-west of France). In total, 99 parasit...
Poster
Full-text available
Photoheterotrophy, which is the ability to utilize organic substrates and harvest light energy, occurs in a broad range of microbes. Aerobic anoxygenic phototrophic (AAP) bacteria are photoheterotrophs that require oxygen for their growth and for bacteriochlorophyll a synthesis. In the Arctic Ocean, we actually observe an increase in solar radiatio...
Article
Full-text available
In Europe, the gastropod Crepidula fornicata is an invasive species characterized by a long reproductive period (from February to November). Thus, its larvae are exposed to variations in available food sources (in terms of quantity and quality). We aimed to investigate if bacteria could contribute to larval food both in presence or absence of phyto...
Article
Full-text available
Biological communities populating the Mediterranean Sea, which is situated at the northern boundary of the subtropics, are often claimed to be particularly affected by global warming. This is indicated, for instance, by the introduction of (sub)tropical species of fish or invertebrates that can displace local species. This raises the question of wh...