A5023481764- Aquatic Ecosystems and Phytoplankton Dynamics
- Marine and coastal ecosystems
- Biocrusts and Microbial Ecology
- Microbial Community Ecology and Physiology
- Protist diversity and phylogeny
- Diatoms and Algae Research
- Aquatic Ecosystems and Biodiversity
- Marine Toxins and Detection Methods
- Freshwater macroinvertebrate diversity and ecology
- Geology and Paleoclimatology Research
- Environmental DNA in Biodiversity Studies
- Pesticide and Herbicide Environmental Studies
- Atmospheric chemistry and aerosols
- Paleontology and Stratigraphy of Fossils
- Algal biology and biofuel production
- Soil erosion and sediment transport
- Environmental Toxicology and Ecotoxicology
- Water Quality and Pollution Assessment
- Geological formations and processes
- Underwater Vehicles and Communication Systems
- Aquatic Invertebrate Ecology and Behavior
- Aquatic and Environmental Studies
- Wastewater Treatment and Nitrogen Removal
- Slime Mold and Myxomycetes Research
- Soil and Water Nutrient Dynamics
Laboratoire Microorganismes Génome et Environnement
2015-2024
Université Clermont Auvergne
2013-2024
Centre National de la Recherche Scientifique
2011-2023
Clermont Université
2010-2023
Université Jean Monnet
2004
Abstract Bacteria play key roles in the function and diversity of aquatic systems, but aside from study specific bloom little is known about or biogeography bacteria associated with harmful cyanobacterial blooms (cyanoHABs). CyanoHAB species are to shape bacterial community composition rely on functions provided by bacteria, leading hypothesized cyanoHAB interactome, a coevolved synergistic interacting species, each necessary for success others. Here, we surveyed microbiome Microcystis...
ABSTRACT With the aim of explaining variations in microcystin (MC) concentrations during cyanobacterial blooms, we studied several Microcystis aeruginosa populations blooming different freshwater ecosystems located same geographical area. As assessed by real-time PCR, it appeared that potentially MC-producing cells ( mcyB + ) were predominant (70 to 100%) all these M. populations, with exception one population which non-MC-producing always dominated. Apart from Grangent Reservoir, found...
Many species of phytoplankton are susceptible to parasitism by fungi from the phylum Chytridiomycota (i.e. chytrids). However, few studies have reported effects fungal parasites on filamentous cyanobacterial blooms. To investigate missing components bloom ecosystems, we examined an entire field cyanobacterium Anabaena macrospora for evidence chytrid infection in a productive freshwater lake, using high resolution sampling strategy. A. was infected two genus Rhizosiphon which similar life...
Summer cyanobacterial blooms exhibit a dynamic interplay between toxic and non-toxic genotypes, significantly influencing the cyanotoxin levels within lake. The challenge lies in accurately predicting these toxin concentrations due to significant temporal fluctuations proportions of genotypes. Typically, genotypes dominate during early late summer periods, while variants prevail mid-summer. To dissect this phenomenon, we propose model that accounts for competitive interaction as well...
The dynamics of benthic colonies Microcystis aeruginosa (cyanobacteria) play an important part in the formation summer bloom underlying many harmful effects. Because this phase remains somewhat unknown, we developed approach using flow cytometry to follow esterase activity species Grangent reservoir. cyanobacteria extracted from two layers sediment (0–2 cm and 2–4 deep) was measured weekly, as indicator viability, by with carboxyfluorescein diacetate. In parallel, concentration estimated...
Microcystis aeruginosa is a toxic cyanobacterium, which able to bloom in wide range of freshwater ecosystems. By sequencing the Internal Transcribed Spacer (ITS) ribosomal operon, we compared genetic composition several French bloom-forming M. populations from two reservoirs located on Loire River, at sampling points between these reservoirs, and finally ponds closely linked this river. No significant difference was found diversity six but evidenced strong differentiation most populations....
Analysis of a sediment core taken from the Grangent reservoir in 2004 showed presence high concentrations Microcystis aeruginosa Kütz. colonies at surface (250 · mL −1 ) and also depths 25–35 cm (2300 colonies·mL 70 (600 ). Measurements radioactive isotopes ( 7 Be, 137 Cs, 241 Am) along with photographic analysis were used to date deep layers: layer located −30 dates summer 2003, that −70 1990 1991. The physiological morphological conditions those benthic compared planktonic using several...
We propose a double staining method based on the combination of two fluorochromes, calcofluor white (CFW; specific chitinous fluorochrome) and SYTOX green (nucleic acid stain), coupled to epifluorescence microscopy for counting, identifying, investigating fecundity parasitic fungi phytoplankton putative relationships established between hosts their chytrid parasites. The was applied freshwater samples collected over successive years during terminal period autumnal cyanobacterial blooms in...
Global warming and eutrophication contribute to the worldwide increase in cyanobacterial blooms, level of biomass is strongly associated with rises methane emissions from surface lake waters. Hence, methane-metabolizing microorganisms may be important for modulating carbon flow blooms. Here, we surveyed methanogenic methanotrophic communities floating Microcystis aggregates 10 lakes spanning four continents, through sequencing 16S rRNA functional marker genes. Methanogenic archaea (mainly...
The benthic recruitment of Microcystis was simulated in vitro order to characterize the colonies recruited and study impact intracellular extracellular microcystins (MCs), influence colony size on process. We observed dynamics consisting a lag phase followed by peak then return low rates, mainly controlled passive resuspension throughout experiment, physiological processes during peak. Ninety‐seven percent were <160 μm maximum length, their cells contained much greater amounts MCs (0.26 ±...
Abstract Parasitism is certainly one of the most important driving biotic factors cyanobacterial blooms which remains largely understudied. Among these parasites, fungi from phylum Chytridiomycota (i.e. chytrids) are only eukaryotic microorganisms infecting cyanobacteria. Here, we address spatiotemporal dynamics host Dolichospermum macrosporum ( syn. Anabaena macrospora ) and its associated chytrid Rhizosiphon spp., in an eutrophic lake by studying spatial (vertical, horizontal) temporal...
Monitoring of water and surface sediment in a French eutrophic lake (Lake Aydat) was carried out over 2-year period order to determine whether akinetes could be representative the most recent bloom estimate their germination potential. Sediment analysis revealed two akinete species, Dolichospermum macrosporum Dolichospermumflos-aquae, present same proportions as observed for pelagic populations. Moreover, similar spatial patterns vegetative cells column distributions suggest that may...
The benthic recruitment of Microcystis was assessed in vitro order (i) to compare the relative influence main abiotic factors, and (ii) investigate impact duration life stage. Different populations sampled a 45 m deep artificial lake, with phases ranging from few weeks almost 3 years, were used test three temperatures (4, 7 17°C), absence or presence light sediment mixing on recruitment. In this study, only physical factor found promote recruitment, indicating that passive resuspension plays...
AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsSpecials 36:117-122 (2004) - doi:10.3354/ame036117 Frequency of dividing cells and viability Microcystis aeruginosa in sediment a eutrophic reservoir Delphine Latour*, Hervé Giraudet, Jean-Louis Berthon Laboratoire de Biologie Animale et Appliquée, Université Jean Monnet, 23 rue Paul Michelon, 42023 Saint-Etienne Cedex 2, France...
Microcystis is a toxic colony-forming cyanobacterium, which can bloom in wide range of freshwater ecosystems. Despite the ecological advantage colonial form, few studies have paid attention to size colonies field. With aim evaluating impact fluctuating physical environment on colony size, genotypic composition and potential population, we investigated five different classes Grangent reservoir (France). By sequencing internal transcribed spacer ribosomal operon, evidenced changes genetic...
Microcystis is a toxic freshwater cyanobacterium with an annual life cycle characterized by the alternation of planktonic proliferation stage in summer and benthic resting winter. Given importance both stages for development survival population, we investigated genotypic composition subpopulations from Grangent reservoir (France) during two distinct periods. Our results showed succession different dominant genotypes sediment as well water all along study periods some common to compartments....