scholarly journals Biogeochemical Niche of Magnetotactic Cocci Capable of Sequestering Large Polyphosphate Inclusions in the Anoxic Layer of the Lake Pavin Water Column

2022 ◽  
Vol 12 ◽  
Author(s):  
Cécile C. Bidaud ◽  
Caroline L. Monteil ◽  
Nicolas Menguy ◽  
Vincent Busigny ◽  
Didier Jézéquel ◽  
...  
Keyword(s):  
Water Column ◽  
Light And Electron Microscopy ◽  
Environmental Parameters ◽  
Aqueous System ◽  
Calcium Carbonates ◽  
Chemical Gradients ◽  
Anoxic Layer ◽  
Geochemical Analyses ◽  
Lake Pavin ◽  
Biogeochemical Niche

Magnetotactic bacteria (MTB) are microorganisms thriving mostly at oxic–anoxic boundaries of aquatic habitats. MTB are efficient in biomineralising or sequestering diverse elements intracellularly, which makes them potentially important actors in biogeochemical cycles. Lake Pavin is a unique aqueous system populated by a wide diversity of MTB with two communities harbouring the capability to sequester not only iron under the form of magnetosomes but also phosphorus and magnesium under the form of polyphosphates, or calcium carbonates, respectively. MTB thrive in the water column of Lake Pavin over a few metres along strong redox and chemical gradients representing a series of different microenvironments. In this study, we investigate the relative abundance and the vertical stratification of the diverse populations of MTB in relation to environmental parameters, by using a new method coupling a precise sampling for geochemical analyses, MTB morphotype description, and in situ measurement of the physicochemical parameters. We assess the ultrastructure of MTB as a function of depth using light and electron microscopy. We evidence the biogeochemical niche of magnetotactic cocci, capable of sequestering large PolyP inclusions below the oxic–anoxic transition zone. Our results suggest a tight link between the S and P metabolisms of these bacteria and pave the way to better understand the implication of MTB for the P cycle in stratified environmental conditions.

scholarly journals Relationships between Environmental Factors and Pathogenic Vibrios in the Northern Gulf of Mexico

2010 ◽  
Vol 76 (21) ◽  
pp. 7076-7084 ◽  
Author(s):  
C. N. Johnson ◽  
A. R. Flowers ◽  
N. F. Noriea ◽  
A. M. Zimmerman ◽  
J. C. Bowers ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Water Column ◽  
Vibrio Vulnificus ◽  
Environmental Parameters ◽  
Sampling Period ◽  
Pathogenicity Factor ◽  
Hemolysin Gene ◽  
Thermostable Direct Hemolysin ◽  
Pathogenic Vibrios ◽  
Abundance And Distribution

ABSTRACT Although autochthonous vibrio densities are known to be influenced by water temperature and salinity, little is understood about other environmental factors associated with their abundance and distribution. Densities of culturable Vibrio vulnificus containing vvh (V. vulnificus hemolysin gene) and V. parahaemolyticus containing tlh (thermolabile hemolysin gene, ubiquitous in V. parahaemolyticus), tdh (thermostable direct hemolysin gene, V. parahaemolyticus pathogenicity factor), and trh (tdh-related hemolysin gene, V. parahaemolyticus pathogenicity factor) were measured in coastal waters of Mississippi and Alabama. Over a 19-month sampling period, vibrio densities in water, oysters, and sediment varied significantly with sea surface temperature (SST). On average, tdh-to-tlh ratios were significantly higher than trh-to-tlh ratios in water and oysters but not in sediment. Although tlh densities were lower than vvh densities in water and in oysters, the opposite was true in sediment. Regression analysis indicated that SST had a significant association with vvh and tlh densities in water and oysters, while salinity was significantly related to vibrio densities in the water column. Chlorophyll a levels in the water were correlated significantly with vvh in sediment and oysters and with pathogenic V. parahaemolyticus (tdh and trh) in the water column. Furthermore, turbidity was a significant predictor of V. parahaemolyticus density in all sample types (water, oyster, and sediment), and its role in predicting the risk of V. parahaemolyticus illness may be more important than previously realized. This study identified (i) culturable vibrios in winter sediment samples, (ii) niche-based differences in the abundance of vibrios, and (iii) predictive signatures resulting from correlations between environmental parameters and vibrio densities.

Members of candidate divisions OP11, OD1 and SR1 are widespread along the water column of the meromictic Lake Pavin (France)

2010 ◽  
Vol 192 (7) ◽  
pp. 559-567 ◽  
Author(s):  
Guillaume Borrel ◽  
Anne-Catherine Lehours ◽  
Corinne Bardot ◽  
Xavier Bailly ◽  
Gérard Fonty
Keyword(s):  
Water Column ◽  
Meromictic Lake ◽  
Lake Pavin

Hydrochemistry and carbonate sediment characterisation of Bacalar Lagoon, Mexican Caribbean

2019 ◽  
Vol 70 (3) ◽  
pp. 382 ◽  
Author(s):  
Nidia I. Tobón Velázquez ◽  
Mario Rebolledo Vieyra ◽  
Adina Paytan ◽  
Kyle H. Broach ◽  
Laura M. Hernández Terrones
Keyword(s):  
Trace Elements ◽  
Water Column ◽  
Saturation Index ◽  
Major Elements ◽  
Anthropogenic Sources ◽  
Pollution Indices ◽  
Mexican Caribbean ◽  
High Concentrations ◽  
Geochemical Analyses ◽  
Changes Over Time

The aim of the study is to determine the distribution of trace and major elements in the water and in the sediments of the south part of the Bacalar Lagoon and to identify the sources of the trace elements and their changes over time. The western part of the lagoon water column is characterised by high concentrations of Ca2+, HCO3– and Sr2+, derived from groundwater input. In contrast, the eastern part of the lagoon is characterised by high concentrations of Mg2+, Na+ and Cl–. The lagoon is not affected by present-day seawater intrusion. Water column and sediment geochemical analyses performed in Bacalar Lagoon show clear spatial distribution of different parameters. The saturation index of the water column indicates three main groups: (1) a zone oversaturated with regard to aragonite, calcite and dolomite; (2) an undersaturated area where all three minerals are dissolving; and (3) an area with calcite equilibrium and undersaturation with regard to the other minerals. Herein we present the first measurements of trace element (Ba2+, Mn2+, K+, Ni2+, Zn2+) concentrations in carbonates obtained from sediments in Bacalar Lagoon. In order to evaluate whether the trace elements are derived from natural or anthropogenic sources, four pollution indices were calculated. The results confirmed that Bacalar Lagoon sediments are not contaminated with Ni2+, K+, Mn2+ and Ba2+, and that the Zn2+ seems to have a predominantly anthropogenic origin.

scholarly journals Biogeochemistry of manganese in Lake Matano, Indonesia

2011 ◽  
Vol 8 (2) ◽  
pp. 4063-4106 ◽  
Author(s):  
C. Jones ◽  
S. A. Crowe ◽  
A. Sturm ◽  
K. L. Leslie ◽  
L. C. W. MacLean ◽  
...  
Keyword(s):  
Water Column ◽  
Environmental Parameters ◽  
Transport Modeling ◽  
Ch4 Oxidation ◽  
X Ray ◽  
Lake Matano ◽  
Sinking Particles ◽  
Reaction Transport ◽  
Kinetics Of ◽  
Mn Oxides

Abstract. This study explores Mn biogeochemistry in a stratified, ferruginous lake. Intense Mn cycling occurs in the chemocline where Mn is recycled at least 15 times before sedimentation. The kinetics of Mn oxidation in Lake Matano are similar to other studied environments, implying that Mn oxidation is relatively insensitive to environmental parameters and may be controlled by similar mechanisms in diverse settings. The product of biologically catalyzed Mn oxidation in Lake Matano is birnessite. Although there is evidence for abiotic Mn reduction with Fe(II), Mn reduction likely occurs through a variety of pathways. The flux of Fe(II) is insufficient to balance the reduction of Mn at 125 m depth in the water column, and Mn reduction could be a significant contributor to CH4 oxidation. By combining results from synchrotron-based X-ray fluorescence and X-ray spectroscopy, extractions of sinking particles, and reaction transport modeling, we find the kinetics of Mn reduction in the lake's reducing waters are sufficiently rapid to preclude the deposition of Mn oxides from the water column to the sediments underlying anoxic water. Rather, Mn is likely sequestered in these sediments as pseudo kutnahorite. This has strong implications for the interpretation of the sedimentary Mn record.

scholarly journals Environmental properties of the southern Gulf of Aqaba, Red Sea, Egypt

2012 ◽  
Vol 13 (2) ◽  
pp. 179 ◽  
Author(s):  
M.M. DORGHAM ◽  
M.M. EL-SHERBINY ◽  
M.H. HANAFI
Keyword(s):  
Dissolved Oxygen ◽  
Water Column ◽  
Chlorophyll A ◽  
Red Sea ◽  
Environmental Parameters ◽  
Gulf Of Aqaba ◽  
High Concentration ◽  
Environmental Properties ◽  
Epipelagic Zone ◽  
Deep Layers

Environmental properties (temperature, dissolved oxygen, nutrients and chlorophyll a) of the epipelagic zone off SharmEl-Sheikh, Red Sea, Egypt were studied seasonally throughout a year from March 1995 to March 1996. Water samples werecollected from five water depths (0, 25, 50, 75 & 100 m). The studied parameters exhibited clear seasonal variability along the water column. The vertical distribution of water temperature showed thermal homogeneity during most seasons, and thermal stratification in summer. Dissolved oxygen attained slightly high concentrations (5.3-7.8 mg l-1) in the whole water column, with slight seasonal variation. The concentrations of nutrients reflected dominant oligotrophic conditions in the epipelagic zone and occasional mesotrophic status at some depths. Phosphate fluctuated between 0-0.7 μM, ammonium (0-2.27 μM), nitrite (0-0.72 μM), nitrate (0-1.49 μM) and silicate (0-6.48 M). Phytoplankton biomass was generally low in the epipelagic zone throughout the study, whereas chlorophyll a was less than 0.5 μg l-1, except relatively high concentration (0.7-1.12 μg l-1) in deep layers in spring. In comparison with previous studies on the Gulf of Aqaba all environmental parameters during present study showed pronouncedlydifferent values.

scholarly journals Distribution of bacterial populations in a stratified fjord (mariager fjord, denmark) quantified by in situ hybridization and related to chemical gradients in the water column

1996 ◽  
Vol 62 (10) ◽  
pp. 3914-3914
Author(s):  
N B Ramsing ◽  
H Fossing ◽  
T G Ferdelman ◽  
F Andersen ◽  
B Thamdrup
Keyword(s):  
In Situ Hybridization ◽  
Aluminum Oxide ◽  
Pore Size ◽  
Water Column ◽  
Bacterial Populations ◽  
Chemical Gradients

Volumn 62, no. 4, p. 1392, lines 37 and 38: "Aluminum oxide filters (0.2 mm pore size; Anopore; Millipore GmbH, Eschborn, Germany)" should read "Aluminum oxide filters (0.2 (mu)m pore size; Anopore; Whatman, Inc., Clifton, N.J.)." Page 1403, reference 15: "Fenchel, T." should read "Fenchel, T., L. D. Kristensen, and L. Rasmussen." [This corrects the article on p. 1391 in vol. 62.].

scholarly journals Susane, a device for sampling chemical gradients in the benthic water column

2019 ◽  
Author(s):  
Joël Knoery ◽  
Daniel Cossa ◽  
Bastien Thomas ◽  
Germain Gregory ◽  
Sylvain Rigaud
Keyword(s):  
Water Column ◽  
Chemical Gradients

Biomineralization of iron-phosphates in the water column of Lake Pavin (Massif Central, France)

2014 ◽  
Vol 126 ◽  
pp. 78-96 ◽  
Author(s):  
Julie Cosmidis ◽  
Karim Benzerara ◽  
Guillaume Morin ◽  
Vincent Busigny ◽  
Oanez Lebeau ◽  
...  
Keyword(s):  
Water Column ◽  
Massif Central ◽  
Iron Phosphates ◽  
Lake Pavin

scholarly journals HPM Live μ for a full CLEM workflow

2020 ◽  
Author(s):  
Xavier Heiligenstein ◽  
Marit de Beer ◽  
Jérôme Heiligenstein ◽  
Frédérique Eyraud ◽  
Laurent Manet ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Imaging Techniques ◽  
Light And Electron Microscopy ◽  
Environmental Parameters ◽  
Live Imaging ◽  
Chemical Fixation ◽  
Protein Fluorescence ◽  
Spectroscopic Information ◽  
The Many ◽  
Almost All

ABSTRACTWith the development of advanced imaging methods that took place in the last decade, the spatial correlation of microscopic and spectroscopic information - known as multimodal imaging or correlative microscopy (CM) - has become a broadly applied technique to explore biological and biomedical materials at different length scales. Among the many different combinations of techniques, Correlative Light and Electron Microscopy (CLEM) has become the flagship of this revolution.Where light (mainly fluorescence) microscopy can be used directly for the live imaging of cells and tissues, for almost all applications, electron microscopy (EM) requires fixation of the biological materials. Although sample preparation for EM is traditionally done by chemical fixation and embedding in a resin, rapid cryogenic fixation (vitrification) has become a popular way to avoid the formation of artefacts related to the chemical fixation/embedding procedures. During vitrification, the water in the sample transforms into an amorphous ice, keeping the ultrastructure of the biological sample as close as possible to the native state. One immediate benefit of this cryo-arrest is the preservation of protein fluorescence, allowing multi-step multi-modal imaging techniques for CLEM.To further explore the potential of cryo-fixation, we developed a high-pressure freezing (HPF) system that allows vitrification under different environmental parameters and applied it in different CLEM workflows. In this chapter, we introduce our novel HPF live μ instrument with a focus on its coupling to a light microscope. We elaborate on the optimization of sample preservation and the time needed to capture a biological event, going from live imaging to cryo-arrest using HPF. We will address the adaptation of HPF to novel correlation workflows related to the forthcoming transition from imaging 2D (cell monolayers) to imaging 3D samples (tissue) and the associated importance of homogeneous deep vitrification. Lastly, we will discuss the potential of our HPM within CLEM protocols especially for correlating live imaging using the Zeiss LSM900 with electron microscopy.

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