Mass-Independent Fractionation of Even and Odd Mercury Isotopes during Atmospheric Mercury Redox Reactions.

Mass-independent fractionation (MIF) of stable even mass number mercury (Hg) isotopes is observed in rainfall and gaseous elemental Hg globally and is used to quantify atmospheric Hg deposition pathways. The chemical reaction and underlying even-Hg MIF mechanism are unknown however and speculated to be caused by Hg photo-oxidation on aerosols at the tropopause. Here, we investigate the Hg isotope composition of free tropospheric Hg and oxidized Hg forms at the high-altitude Pic du Midi Observatory.

Biogeochemical model of nitrogen cycling in Ahe (French Polynesia), a South Pacific coral atoll with pearl farming.

A biogeochemical model (ECO3M-Atoll) was configured to simulate the lower food web in Ahe Atoll lagoon where phytoplankton is mostly nitrogen limited. Understanding the dynamics of phytoplankton - the main food source for oysters - is crucial for the management and the allocation of new pearl farming sites. After parametrizing the model with in situ observations, we tested different hypotheses about nitrogen cycling (benthic remineralization, atmospheric N fixation, etc.

Explicit and implicit network connectivity: Analytical formulation and application to transport processes.

Connectivity is a fundamental structural feature of a network that determines the outcome of any dynamics that happens on top of it. However, an analytical approach to obtain connection probabilities between nodes associated with to paths of different lengths is still missing. Here, we derive exact expressions for random-walk connectivity probabilities across any range of numbers of steps in a generic temporal, directed, and weighted network.

Future changes to the upper ocean Western Boundary Currents across two generations of climate models.

Western Boundary Currents (WBCs) are important for the oceanic transport of heat, dissolved gases and nutrients. They can affect regional climate and strongly influence the dispersion and distribution of marine species. Using state-of-the-art climate models from the latest and previous Climate Model Intercomparison Projects, we evaluate upper ocean circulation and examine future projections, focusing on subtropical and low-latitude WBCs.

Virome Diversity among Mosquito Populations in a Sub-Urban Region of Marseille, France.

Some mosquito species have significant public health importance given their ability to transmit major diseases to humans and animals, making them the deadliest animals in the world. Among these, the (.) genus is a vector of several viruses such as Dengue, Chikungunya, and Zika viruses that can cause serious pathologies in humans.

Temperature differently affected methanogenic pathways and microbial communities in sub-Antarctic freshwater ecosystems.

Freshwater ecosystems are responsible for an important part of the methane (CH) emissions which are likely to change with global warming. This study aims to evaluate temperature-induced (from 5 to 20 °C) changes on microbial community structure and methanogenic pathways in five sub-Antarctic lake sediments from Magallanes strait to Cape Horn, Chile. We combined in situ CH flux measurements, CH production rates (MPRs), gene abundance quantification and microbial community structure analysis (metabarcoding of the 16S rRNA gene).

Temperate and tropical coastal waters share relatively similar microbial biofilm communities while free-living or particle-attached communities are distinct.

Free-living (FL) marine microbial communities differ from those attached to particles (PA). Likewise, biofilms (B) colonizing artificial surfaces, including plastics or ship hulls, hardly resemble their planktonic surroundings. However, few studies have examined the effect of the environment on these lifestyles and on the source of organisms colonizing marine surfaces.

Pelagic stocks and carbon and nitrogen uptake in a pearl farming atoll (Ahe, French Polynesia).

This study reports the first measurements of nitrogen uptake and new data on carbon fixation (N/C incorporation) for two size-fractionated phytoplankton (<2 μm and >2 μm), on organic matter, and phytoplankton stocks in Ahe lagoon. Data were collected between November and December 2017, during the hot season with prevailing trade winds. Ammonium and nitrate uptake data (7.

Isolation and Characterization of Phage vB_Gva_AB1, a Bacteriophage Infecting a Clinical Strain of Gardnerella vaginalis.

is the presumed causative agent of bacterial vaginosis. Here, we describe the complete genome sequence of phage vB_Gva_AB1, induced from a vaginal bacterial strain from a woman suffering with bacterial vaginosis. The phage double-stranded DNA (dsDNA) genome is 50,268 bp long with a GC content of 39.

Type II photosensitized oxidation in senescent microalgal cells at different latitudes: Does low under-ice irradiance in polar regions enhance efficiency?

Comparison of Type II photosensitized oxidation of lipids (the photodynamic effect) and photodegradation of chlorophyll (sensitizer photobleaching) in samples of particulate matter collected previously from locations representing a diverse range of latitudes reveals an enhancement of the photooxidation of lipids at the expense of chlorophyll photodegradation in the polar regions. The efficiency of the photodynamic effect appears to be particularly high in sinking particles collected under sea ice and is attributed to the rapid settling of highly aggregated sympagic algae to depths of low light transmission favouring the photodynamic effect at the expense of photobleaching of the sensitizer. Paradoxically, the low efficiency of Type II photosensitized oxidation of lipids observed in temperate and equatorial regions is associated with high solar irradiances in these regions.

Viability and stress state of bacteria associated with primary production or zooplankton-derived suspended particulate matter in summer along a transect in Baffin Bay (Arctic Ocean).

In the framework of the GreenEdge Project (whose the general objective is to understand the dynamic of the phytoplankton spring bloom in Arctic Ocean), lipid composition and viability and stress state of bacteria were monitored in sea ice and suspended particulate matter (SPM) samples collected in 2016 along a transect from sea ice to open water in Baffin Bay (Arctic Ocean). Lipid analyses confirmed the dominance of diatoms in the bottommost layer of ice and suggested (i) the presence of a strong proportion of micro-zooplankton in SPM samples collected at the western ice covered St 403 and St 409 and (ii) a high proportion of macro-zooplankton (copepods) in SPM samples collected at the eastern ice covered St 413 and open water St 418. The use of the propidium monoazide (PMA) method allowed to show a high bacterial mortality in sea ice and in SPM material collected in shallower waters at St 409 and St 418.

Trace Metal Contamination Impacts Predicted Functions More Than Structure of Marine Prokaryotic Biofilm Communities in an Anthropized Coastal Area.

Trace metal (TM) contamination in marine coastal areas is a worldwide threat for aquatic communities. However, little is known about the influence of a multi-chemical contamination on both marine biofilm communities' structure and functioning. To determine how TM contamination potentially impacted microbial biofilms' structure and their functions, polycarbonate (PC) plates were immerged in both surface and bottom of the seawater column, at five sites, along strong TM contamination gradients, in Toulon Bay.

Development and validation of a multiplex qPCR assay for detection and relative quantification of HPV16 and HPV18 E6 and E7 oncogenes.

Human papillomaviruses (HPV) play a key role in promoting human anogenital cancers. Current high-risk HPV screening or diagnosis tests involve cytological or molecular techniques mostly based on qualitative HPV DNA detection. Here, we describe the development of a rapid quantitative polymerase chain reaction (qPCR) detection test of HPV16 and HPV18 oncogenes (E6 and E7) normalized on human gene encoding GAPDH.

Microplastic in atmospheric fallouts of a developing Southeast Asian megacity under tropical climate.

Microplastics in atmospheric fallouts from a developing megacity influenced by a tropical monsoon climate were investigated during a year. Three sites were selected according to the surrounding population density, the land use and occupation. The microplastic deposition fluxes varied between of 71-917 items m d, for an observation size range of 300-5000 μm.

Elutriate preparation affects embryo development test with Paracentrotus lividus: An in-depth study on the differences between two protocols and three different sediment/water mixing times.

Coastal areas are under continuous and increasing pressure from different human activities. A mixture of contaminants (e.g.

Oyster hemolymph is a complex and dynamic ecosystem hosting bacteria, protists and viruses.

Background: The impact of the microbiota on host fitness has so far mainly been demonstrated for the bacterial microbiome. We know much less about host-associated protist and viral communities, largely due to technical issues. However, all microorganisms within a microbiome potentially interact with each other as well as with the host and the environment, therefore likely affecting the host health.

The Kaumoebavirus LCC10 Genome Reveals a Unique Gene Strand Bias among "Extended ".

infects the amoeba and has recently been described as a distant relative of the African swine fever virus. To characterize the diversity and evolution of this novel viral genus, we report here on the isolation and genome sequencing of a second strain of , namely LCC10. Detailed analysis of the sequencing data suggested that its 362-Kb genome is linear with covalently closed hairpin termini, so that DNA forms a single continuous polynucleotide chain.

Analysis of organellar genomes in brown algae reveals an independent introduction of similar foreign sequences into the mitochondrial genome.

Kelp species (Laminariales, Phaeophyceae) are globally widespread along temperate to Polar rocky coastal lines. Here we analyse the mitochondrial and chloroplast genomes of Laminaria rodriguezii, in comparison to the organellar genomes of other kelp species. We also provide the complete mitochondrial genome sequence of another endemic kelp species from a Polar habitat, the Arctic Laminaria solidungula.

Mesopelagic microbial carbon production correlates with diversity across different marine particle fractions.

The vertical flux of marine snow particles significantly reduces atmospheric carbon dioxide concentration. In the mesopelagic zone, a large proportion of the organic carbon carried by sinking particles dissipates thereby escaping long term sequestration. Particle associated prokaryotes are largely responsible for such organic carbon loss.

Evolution of ribosomal protein network architectures.

To perform an accurate protein synthesis, ribosomes accomplish complex tasks involving the long-range communication between its functional centres such as the peptidyl transfer centre, the tRNA bindings sites and the peptide exit tunnel. How information is transmitted between these sites remains one of the major challenges in current ribosome research. Many experimental studies have revealed that some r-proteins play essential roles in remote communication and the possible involvement of r-protein networks in these processes have been recently proposed.

The Ocean barcode atlas: A web service to explore the biodiversity and biogeography of marine organisms.

The Ocean Barcode Atlas (OBA) is a user friendly web service designed for biologists who wish to explore the biodiversity and biogeography of marine organisms locked in otherwise difficult to mine planetary scale DNA metabarcode data sets. Using just a web browser, a comprehensive picture of the diversity of a taxon or a barcode sequence is visualized graphically on world maps and interactive charts. Interactive results panels allow dynamic threshold adjustments and the display of diversity results in their environmental context measured at the time of sampling (temperature, oxygen, latitude, etc).

Surface ocean microbiota determine cloud precursors.

One pathway by which the oceans influence climate is via the emission of sea spray that may subsequently influence cloud properties. Sea spray emissions are known to be dependent on atmospheric and oceanic physicochemical parameters, but the potential role of ocean biology on sea spray fluxes remains poorly characterized. Here we show a consistent significant relationship between seawater nanophytoplankton cell abundances and sea-spray derived Cloud Condensation Nuclei (CCN) number fluxes, generated using water from three different oceanic regions.

Phylogenomic fingerprinting of tempo and functions of horizontal gene transfer within ochrophytes.

Horizontal gene transfer (HGT) is an important source of novelty in eukaryotic genomes. This is particularly true for the ochrophytes, a diverse and important group of algae. Previous studies have shown that ochrophytes possess a mosaic of genes derived from bacteria and eukaryotic algae, acquired through chloroplast endosymbiosis and from HGTs, although understanding of the time points and mechanisms underpinning these transfers has been restricted by the depth of taxonomic sampling possible.

Contribution of Posidonia oceanica meadows in the context of climate change mitigation in the Mediterranean Sea.

Coastal marine vegetation has been recently highlighted for its highly efficient carbon storage capacity. Among the sixty-four species of seagrass, Posidonia oceanica, a Mediterranean endemic species, appears to be the most effective in carbon fixation and storage. Based on new data from the study of one of the largest P.