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Introduction
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September 2009 - July 2013
Publications
Publications (49)
Shrimp rearing generate organic waste that is trapped in the pond sediment. In
excess, these wastes may impair aquaculture ecosystem and shrimps’ health.
To promote the biological oxidation of accumulated organic waste, the pond is
drained and dried at the end of each production cycle. However, this practice
is not always conducive to maintaining m...
Background
In New-Caledonia, at the end of each shrimp production cycle, earthen ponds are drained and dried to enhance microbial decomposition of nutrient-rich waste trapped in the sediment during the rearing. However, excessive ponds drying may not be suitable for the decomposition activities of microorganisms. Halophytes, salt tolerant plants, n...
Background
Aquacultured animals are reared in water hosting various microorganisms with which they are in close relationships during their whole lifecycle as some of these microorganisms can be involved in their host’s health or physiology. In aquaculture hatcheries, understanding the interactions existing between the natural seawater microbiota, t...
Aquacultured animals are reared in water, where they interact with microorganisms which can be involved in their development, immunity, and disease. It is therefore interesting to study the rearing water microbiota, especially in the hatcheries of the Pacific blue shrimp Penaeus stylirostris, where larval mass mortalities occur. In this study, usin...
The many ecological niches present in an organism harbor distinct microorganisms called microbiota. Different factors can influence the establishment of these commensal microbial communities. In a previous article, we have concluded that some bacterial lineages associated with the early larval stages of the Pacific blue shrimp Litopenaeus stylirost...
Plant culture integration within aquaculture activities is a topic of recent interest with economic and environmental benefits. Shrimp farming activities generate nutrient-rich waste trapped in the sediments of farming ponds or release in the mangrove area. Thus, we investigate if the halophytes species naturally growing around the pond can use nit...
This study focused on the investigation of Actinomycetes strains isolated from sediment sample of Cheliff River estuary in Mostaganem (North-west of Algeria). Identification of the 5 strains of Actinomycetes isolated from sediments by morphological, biochemical methods and by16S rRNA gene sequence analysis revealed that four strains belonged to the...
Background
Microbial communities associated with animals are known to be key elements in the development of their hosts. In marine environments, these communities are largely under the influence of the surrounding water. In aquaculture, understanding the interactions existing between the microbiotas of farmed species and their rearing environment c...
The European Parliament recently approved a new law banning single-use plastic items for 2021 such as plastic plates, cutlery, straws, cotton swabs, and balloon sticks. Transition to a bioeconomy involves the substitution of these banned products with biodegradable materials. Several materials such as polylactic acid (PLA), polybutylene adipate ter...
The toxicity of arsenic (As) towards life on Earth is apparent in the dense distribution of genes associated with As detoxification across the tree of life. The ability to defend against As is particularly vital for survival in As-rich shallow submarine hydrothermal ecosystems along the Hellenic Volcanic Arc (HVA), where life is exposed to hydrothe...
The toxicity of arsenic (As) towards life on Earth is apparent in the dense distribution of genes associated with As detoxification across the tree of life. The ability to defend against As is particularly vital for survival in As-rich shallow submarine hydrothermal ecosystems along the Hellenic Volcanic Arc (HVA), where life is exposed to hydrothe...
Plastics are ubiquitous in the oceans and constitute suitable matrices for bacterial attachment and growth. Understanding biofouling mechanisms is a key issue to assessing the ecological impacts and fate of plastics in marine environment. In this study, we investigated the different steps of plastic colonization of polyolefin-based plastics, on the...
The dominant initial phase formed during microbially mediated manganese oxidation is a poorly crystalline birnessite-type phyllomanganate. The occurrence of manganese deposits containing this mineral is of interest for increased understanding of microbial involvement in the manganese cycle. A culture independent molecular approach is used as a firs...
Lava tubes on Earth represent some of the most enticing Martian analog environments when investigating the possibility of past or present life on Mars. Lava tubes provide stable, sheltered environments which are isolated and protected from the radiation on the surface. The microbial mats in these caves further regulate the environment for life, all...
The seafloor sediments of Spathi Bay, Milos Island, Greece, are part of the largest arsenic-CO2-rich
shallow submarine hydrothermal ecosystem on Earth. Here, white and brown deposits cap chemically
distinct sediments with varying hydrothermal influence. All sediments contain abundant genes for
autotrophic carbon fixation used in the Calvin-Benson-B...
Methane and nitrous oxide are potent greenhouse gases (GHGs) that contribute to climate change.
Coastal sediments are important GHG producers, but the contribution of macrofauna (benthic
invertebrates larger than 1 mm) inhabiting them is currently unknown. Through a combination of
trace gas, isotope, and molecular analyses, we studied the direct an...
Members of the order Thermococcales are common inhabitants of high-temperature hydrothermal vent systems (black smokers) that are represented in clone libraries mostly by isolates from the Thermococcus genus. We report the complete sequence of a novel species from the Pyrococcus genus, P. kukulkanii strain NCB100, which has been isolated from a fla...
Hydrogen (H2) consumption and methane (CH4) production in pure cultures of three different methanogens were investigated during cultivation with 0, 0.2 and 4.21 μM added nickel (Ni). The results showed that the level of dissolved Ni in the anaerobic growth medium did not notably affect CH4 production in the cytochrome-free methanogenic species Meth...
Element concentrations (μg L-1) in the cell digestion experiments.
(PDF)
Element (Co, Fe, Mo and Ni) concentrations (μg L-1) in wash medium, supernatant and cell pellets in the cell digestion experiments.
(PDF)
Measured accumulated CH4 (μmol) at different incubation times (days).
(PDF)
Hydrogen partial pressure (pH2, Pa) (mean of three replicates) at different incubation times (days).
The empty cells for days 105 and 119 represent too high content of H2 in order to be measured by PP1.
(PDF)
Characterization of a black substance exuding from fractured bedrock in a subterranean tunnel revealed a secondary manganese oxide mineralisation exceptionally enriched in rare earth elements (REE). Concentrations are among the highest observed in secondary ferromanganese precipitates in nature. The tunnel is located in the unsaturated zone at shal...
Climate and human-induced environmental change promote biological regime
shifts between alternate stable states, with implications for ecosystem
resilience, function, and services. While these effects have been shown for
present-day ecosystems, the long-term response of microbial communities has
not been investigated in detail. This study assessed...
Subaerial exposure and oxidation of organic carbon (Corg)-rich rocks is believed to be a key mechanism for the recycling of buried C and S back to Earth’s surface. Importantly, processes coupled to microbial Corg oxidation are expected to shift new biomass δ13Corg composition towards more negative values relative to source. However, there is scarci...
Quantitative PCR data, coupled to sediment geochemistry highlights a situation where arsenotrophy and arsenic detoxification covary with high affinity phosphate uptake genes as a function of the degree of hydrothermal influence, Spathi bay, Milos Island, Greece..
A novel hyperthermophilic, piezophilic anaerobic archaeon, designated as NCB100T, was isolated from a hydrothermal vent flange fragment collected in the Guaymas basin at the hydrothermal vent site named "Rebecca's Roost" at a depth of 1997 m. Enrichment and isolation were done at 100°C under atmospheric pressure. Cells of strain NCB100T are highly...
Climate and human-induced environmental change promotes biological regime shifts between alternate stable states, with implications for ecosystem resilience, function and services. While this has been shown for recent microbial communities, the long-term response of microbial communities has not been investigated in detail. This study investigated...
Protection against arsenic damage in organisms positioned deep in the tree of life points to early evolutionary sensitization. Here, marine sedimentary records reveal a Proterozoic arsenic concentration patterned to glacial-interglacial ages. The low glacial and high interglacial sedimentary arsenic concentrations, suggest deteriorating habitable m...
Increased chemical weathering of trace elements from land to ocean after the Great Oxidation Event is often correlated to biological stimulation near the ocean margins. However, life had to develop strategies to combat the sudden bioavailability of a range of toxic/redox-sensitive elements that became widely accessible because of the GOE. Here, sed...
Shallow submarine hydrothermal ecosystems, located at depth <200m, are extreme environments influenced by both geothermal activity and light. They are described as " high energy environments " fuelling various microbial processes. However, little is known about sediment geochemistry, microbial diversity, or how these components interact and influen...
Active hydrothermal chimneys host diverse microbial communities exhibiting various metabolisms including those involved in various biogeochemical cycles. To investigate microbe-mineral-fluid interactions in hydrothermal chimney and the driver of microbial diversity, a cultural approach using a gas-lift bioreactor was chosen. An enrichment culture w...
Subsurface sediments of the Sonora Margin (Guaymas Basin), located in proximity of active cold seep sites were explored. The taxonomic and functional diversity of bacterial and archaeal communities were investigated from 1 to 10 meters below the seafloor. Microbial community structure and abundance and distribution of dominant populations were asse...
Oceanic basalts host diverse microbial communities with various metabolisms involved in C, N, S, and Fe biogeochemical cycles which may contribute to mineral and glass alteration processes at, and below the seafloor. In order to study the microbial colonization on basaltic glasses and their potential biotic/abiotic weathering products, two coloniza...
Les cheminées et sédiments hydrothermaux actifs du Bassin de Guaymas (Mexique) hébergent diverses communautés microbiennes présentant différents métabolismes, y compris ceux impliqués dans les cycles biogéochimiques du soufre et du fer. Il est établi, que, dans ces écosystèmes dynamiques, les micro-organismes qui dépendent pour leur croissance des...
Extracting DNA from deep subsurface sediments is challenging given the complexity of sediments types, low biomasses, resting structures (spores, cysts) frequently encountered in deep sediments, and the potential presence of enzymatic inhibitors. Promising results for cell lysis efficiency were recently obtained by use of a cryogenic mill (Lipp et a...
MC-ICPMS is now commonly used to detect sub-permil isotopic variations for several metallic chemical elements. High precision isotope ratio measurements are therefore required, necessitating precaution for method validation in order to obtain accurate results. Although mass discrimination is known to be the main analytical bias of this technique, i...
In seafloor hydrothermal systems, Sulfur is an important element present
in various forms such as sulfate, elemental sulfur or sulfide in
hydrothermal fluids and pore waters. Sulfur, as either electron donor or
acceptor, is one element that enables support for microbial life in the
deep biosphere. Traditionally, measurements of 34S/32S ratios
(δ34S...
A novel strictly anaerobic, thermophilic, sulfur-reducing bacterium, designated PH1209(T), was isolated from an East Pacific Rise hydrothermal vent (1 degrees N) sample and studied using a polyphasic taxonomic approach. Cells were Gram-negative, motile rods (approx. 1.60 x 0.40 microm) with a single polar flagellum. Strain PH1209(T) grew at tempera...
