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Introduction
Additional affiliations
December 2019 - present
October 2016 - October 2019
January 2013 - September 2016
Education
September 2008 - October 2012
Publications
Publications (115)
The colonization of land by plants generated opportunities for the rise of new heterotrophic life forms, including humankind. A unique event underpinned this massive change to earth ecosystems—the advent of eukaryotic green algae. Today, an abundant marine green algal group, the prasinophytes, alongside prasinodermophytes and nonmarine chlorophyte...
Critical questions exist regarding the abundance and, especially, the export of picophytoplankton (≤2 µm diameter) in the Arctic. These organisms can dominate chlorophyll concentrations in Arctic regions, which are subject to rapid change. The picoeukaryotic prasinophyte Micromonas grows in polar environments and appears to constitute a large, but...
The climate-sensitive waters of the West Antarctic Peninsula (WAP), including its many fjords, are hot spots of productivity that support multiple marine mammal species. Here, we profiled protistan molecular diversity in a WAP fjord known for high productivity and found distinct spatiotemporal patterns across protistan groups.
The smallest phytoplankton species are key actors in oceans biogeochemical cycling and their abundance and distribution are affected with global environmental changes. Picoalgae (cells <2µm) of the Pelagophyceae class encompass coastal species causative of harmful algal blooms while others are cosmopolitan and abundant in open ocean ecosystems. Des...
The marine picoeukaryote Bathycoccus prasinos has been considered a cosmopolitan alga, although recent studies indicate two ecotypes exist, Clade BI ( B. prasinos ) and Clade BII. Viruses that infect Bathycoccus Clade BI are known (BpVs), but not that infect BII. We isolated three dsDNA prasinoviruses from the Sargasso Sea against Clade BII isolate...
Much is known about how broad eukaryotic phytoplankton groups vary according to nutrient availability in marine ecosystems. However, genus- and species-level dynamics are generally unknown, although important given that adaptation and acclimation processes differentiate at these levels. We examined phytoplankton communities across seasonal cycles i...
Giant viruses are remarkable for their large genomes, often rivaling those of small bacteria, and for having genes thought exclusive to cellular life. Most isolated to date infect nonmarine protists, leaving their strategies and prevalence in marine environments largely unknown. Using eukaryotic single-cell metagenomics in the Pacific, we discovere...
In marine ecosystems viruses are major disrupters of the direct flow of carbon and nutrients to higher trophic levels. While the genetic diversity of several eukaryotic phytoplankton virus groups has been characterized, their infection dynamics are less understood, such that the physiological and ecological implications of their diversity remain un...
Extant eukaryote ecology is primarily sustained by oxygenic photosynthesis, in which chlorophylls play essential roles. The exceptional photosensitivity of chlorophylls allows them to harvest solar energy for photosynthesis, but on the other hand, they also generate cytotoxic reactive oxygen species. A risk of such phototoxicity of the chlorophyll...
Collodaria (Retaria) are important contributors to planktonic communities and biogeochemical processes (e.g., the biologic pump) in oligotrophic oceans. Similarly to corals, Collodaria live in symbiosis with dinoflagellate algae, a relationship that is thought to explain partly their ecological success. In the context of global change, the robustne...
Marine algae perform approximately half of global carbon fixation, but their growth is often limited by the availability of phosphate or other nutrients1,2. As oceans warm, the area of phosphate-limited surface waters is predicted to increase, resulting in ocean desertification3,4. Understanding the responses of key eukaryotic phytoplankton to nutr...
Collodaria (Radiolaria) are important contributors to planktonic communities and biogeochemical processes ( e.g. the biologic pump) in oligotrophic oceans. Similarly to corals, Collodaria live in symbiosis with dinoflagellate algae, a relationship that is thought to explain partly their ecological success. In the context of global change, the robus...
Prasinophytes are widespread marine algae for which responses to nutrient limitation and viral infection are not well understood. We studied the picoprasinophyte, Micromonas pusilla, grown under phosphate‐replete (0.65±0.07 d‐1) and 10‐fold lower (low)‐phosphate (0.11±0.04 d‐1) conditions, and infected by the phycodnavirus MpV‐SP1. Expression of 17...
Ocean surface warming is resulting in an expansion of stratified, low-nutrient environments, a process referred to as ocean desertification [1]. A challenge for assessing the impact of these changes is the lack of robust baseline information on the biological communities that carry out marine photosynthesis. Phytoplankton perform half of global bio...
Protists, which are single-celled eukaryotes, critically influence the ecology and chemistry of marine ecosystems, but genome-based studies of these organisms have lagged behind those of other microorganisms. However, recent transcriptomic studies of cultured species, complemented by meta-omics analyses of natural communities, have increased the am...
Prasinophytes are widespread marine green algae that are related to plants. Cellular abundance of the prasinophyte Micromonas has reportedly increased in the Arctic due to climate-induced changes. Thus, studies of these unicellular eukaryotes are important for marine ecology and for understanding Viridiplantae evolution and diversification.
We gene...
Species determination is crucial in biodiversity research. In tintinnids, identification is based almost exclusively on the lorica, despite its frequent intraspecific variability and interspecific similarity. We suggest updated procedures for identification and, depending on the aim of the study, further steps to obtain morphological, molecular, an...
Since ciliates rarely possess structures that easily fossilize, we are limited in our ability to use paleontological studies to reconstruct the early evolution of this large and ecologically important clade of protists. Tintinnids, a group of loricate (house-forming) planktonic ciliates, are the only group that has a significant fossil record. Puta...
Spliceosomal introns are a hallmark of eukaryotic genes that are hypothesized to play important roles in genome evolution but have poorly understood origins. Although most introns lack sequence homology to each other, recently new families of spliceosomal introns that are repeated hundreds of times in individual genomes have been discovered in a fe...
Phytochrome photosensors control a vast gene network in streptophyte plants, acting as master regulators of diverse growth and developmental processes throughout the life cycle. In contrast with their absence in known chlorophyte algal genomes and most sequenced prasinophyte algal genomes, a phytochrome is found in Micromonas pusilla, a widely dist...
Protists (unicellular eukaryotes) play important roles in marine ecosystems but are tremendously diverse and many remain uncharacterized. Deep-sequencing of a universal marker gene has helped resolve community composition patterns among rare and abundant protistan sequence groups in coastal European waters.
Plant phytochromes are photoswitchable red/far-red photoreceptors that allow competition with neighboring plants for photosynthetically active red light. In aquatic environments, red and far-red light are rapidly attenuated with depth; therefore, photosynthetic species must use shorter wavelengths of light. Nevertheless, phytochrome-related protein...
##Assembly-Data-START## Assembly Method :: ABySS v. 1.3.0; CodonCode v. 4.2 Sequencing Technology :: Sanger dideoxy sequencing; Illumina ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: ABySS v. 1.3.0; CodonCode v. 4.2 Sequencing Technology :: Sanger dideoxy sequencing; Illumina ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode v. 4.2 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode v. 4.2 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: JAZZ v. 2008 Sequencing Technology :: Sanger dideoxy sequencing; Illumina ##Assembly-Data-END##
The species-rich order Tintinnida is a group of planktonic ciliates ubiquitous in coastal marine waters, which can be well-described using molecular estimates of diversity. We studied temporal changes of tintinnid diversity over one year in a coastal Mediterranean Sea location (Villefranche-sur-Mer, France) at five different depths (5, 25, 50, 100...
##Assembly-Data-START## Assembly Method :: Lasergene v. v. 9 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: Lasergene v. v. 9 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: Lasergene v. v. 9 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: Lasergene v. v. 9 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: Lasergene v. v. 9 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: Lasergene v. v. 9 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: Lasergene v. v. 9 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: Lasergene v. v. 9 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: Lasergene v. v. 9 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
Tintinnid species are traditionally distinguished via lorica features. Recently, sequencing has revealed polymorphism, i.e., genetically identical individuals with distinct lorica morphologies. One such polymorphic species is Cyttarocylis ampulla; individuals can display lorica morphologies of formally different species of Cyttarocylis and Petalotr...
Deep-sequencing technologies are becoming nearly routine to describe microbial community composition in environmental samples. The 18S ribosomal DNA (rDNA) pyrosequencing has revealed a vast diversity of infrequent sequences, leading to the proposition of the existence of an extremely diverse microbial 'rare biosphere'. Although rare microbes no do...
La diversité des protistes marins planctoniques, après avoir été historiquement étudiée sur des critères morphologiques, est depuis récemment sujette à une intense recherche à l'aide d'approches moléculaires. Notamment, les études basées sur l'amplification directe de marqueurs moléculaires à partir d'ADN environnemental ont révélées une exceptionn...
We investigated the phylogeny of tintinnids (Ciliophora, Tintinnida) with 62 new SSU-rDNA sequences from single cells of 32 marine and freshwater species in 20 genera, including the first SSU-rDNA sequences for Amphorides, Climacocylis, Codonaria, Cyttarocylis, Parundella, Petalotricha, Undella and Xystonella, and 23 ITS sequences of 17 species in...
##Assembly-Data-START## Assembly Method :: CodonCode aligner v. 2010 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode aligner v. 2010 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode aligner v. 2010 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode aligner v. 2010 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode aligner v. 2010 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode aligner v. 2010 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode aligner v. 2010 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode aligner v. 2010 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode aligner v. 2010 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode aligner v. 2010 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode aligner v. 2010 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode aligner v. 2010 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode aligner v. 2010 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode aligner v. 2010 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode aligner v. 2010 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode aligner v. 2010 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode aligner v. 2010 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode aligner v. 2010 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode aligner v. 2010 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode aligner v. 2010 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: CodonCode aligner v. 2010 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##