Nolwenn Callac

Nolwenn Callac
Institut Français de Recherche pour l'Exploitation de la Mer | Ifremer · Department of Lagoons, Ecosystems and Sustainable Aquaculture in New Caledonia

PhD in geomicrobiology

About

45
Publications
9,319
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494
Citations
Citations since 2016
33 Research Items
437 Citations
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2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
Additional affiliations
September 2009 - July 2013
Université de Bretagne Occidentale
Position
  • PhD Student

Publications

Publications (45)
Article
In New Caledonia, rearing of P. stylirostris is one of the main economic activities; unfortunately, mass larval mortalities cause important production decreases, involving major economic losses for the farmers and the Territory. This phenomenon, which has occurred at any larval stage over the past decade, is poorly understood.
Article
Full-text available
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...
Article
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...
Article
Full-text available
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...
Article
Full-text available
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...
Article
Full-text available
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...
Article
Full-text available
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...
Article
Full-text available
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...
Article
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...
Conference Paper
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...
Article
Full-text available
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...
Article
Full-text available
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...
Article
Full-text available
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...
Article
Full-text available
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...
Data
Element concentrations (μg L-1) in the cell digestion experiments. (PDF)
Data
Element (Co, Fe, Mo and Ni) concentrations (μg L-1) in wash medium, supernatant and cell pellets in the cell digestion experiments. (PDF)
Data
Measured accumulated CH4 (μmol) at different incubation times (days). (PDF)
Data
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)
Article
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...
Article
Full-text available
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...
Article
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...
Presentation
Full-text available
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..
Article
Full-text available
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...
Article
Full-text available
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...
Article
Full-text available
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...
Conference Paper
Full-text available
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...
Conference Paper
Full-text available
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...
Article
Full-text available
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...
Article
Full-text available
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...
Article
Full-text available
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...
Thesis
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...
Article
Full-text available
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...
Conference Paper
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...
Conference Paper
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...
Article
Full-text available
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...

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Projects

Projects (2)
Project
MicroLarve Project In New Caledonia, post-larvae supply is a major difficulty in shrimp aquaculture. This lack of post-larvae becomes a bottleneck for the production. To date, we lack knowledge on the evolution of water physico-chemical quality and biosphere-hydrosphere interactions in the lagoon and on the dynamics of active microbial communities associated with farming. This project proposes to lift the locks on these interactions during the first 10 days of larval breeding of Litopenaeus stylirostris, via the use of multidisciplinary approaches with 3 objectives: 1) Microbial ecology and physico-chemical quality of lagoon waters, 2) Microbial ecology of active microorganisms in larval breeding; 3) Meta-analyzes of the data in order to set up a management strategy for microbial communities. The work of this thesis should contribute to sustainable and ecologically intensive shrimp farming.
Project
The project interfaces biology with geological and environmental geochemistry with special focus on reconstructing biogeochemical processes in modern and ancient marine environments. New perspectives are gained from modern and ancient shallow submarine hydrothermal systems, related to As, Fe, Cu, P and C cycling and microbial influence in the formation of economic mineral deposits and pressures guiding microbial evolution through time.