scholarly journals Iron oxide deposits associated with the ectosymbiotic bacteria in the hydrothermal vent shrimp Rimicaris exoculata

2008 ◽  
Vol 5 (2) ◽  
pp. 1825-1865 ◽  
Author(s):  
L. Corbari ◽  
M.-A. Cambon-Bonavita ◽  
G. J. Long ◽  
F. Grandjean ◽  
M. Zbinden ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Iron Oxides ◽  
Environmental Scanning ◽  
Rimicaris Exoculata ◽  
Transmission Electron ◽  
Iron Oxidizing Bacteria ◽  
Scanning Transmission ◽  
Mid Atlantic Ridge ◽  
Chemoautotrophic Bacteria ◽  
Hydrothermal Ecosystems

Abstract. The Rimicaris exoculata shrimp is considered a primary consumer that dominates the fauna of most Mid-Atlantic Ridge (MAR) hydrothermal ecosystems. These shrimps harbour in their gill chambers an important ectosymbiotic community of chemoautotrophic bacteria associated with iron oxide deposits. The structure and elemental composition of the minerals associated with these bacteria have been investigated by using X-ray microanalyses, light microscopy, and transmission, environmental scanning and scanning transmission electron microscopy. The nature of the iron oxides in shrimps obtained from the Rainbow vent field at 36°14.0' N, has also been determined by Mössbauer spectroscopy. This multidisciplinary approach has revealed that the three step-levels of mineral crust found in the Rimicaris exoculata shrimps consist of heavy concretions formed by nanoparticles of two-line ferrihydrite intermixed with minor inorganic SiO2, (Ca,Mg)SO4, and (Ca,Mg)3(PO4)2 minerals that may stabilise the ferrihydrite form of iron oxides. Morphological observations on the bacteria have revealed their close interactions with these minerals and, thus, indicate the biogenic origin of the iron oxide deposits. The evolution of the bacterial density in the three mineral crust levels is related to the amount of the iron deposits and it is proposed that the lower crust level is the most likely region for the location of the iron-oxidizing bacteria.

scholarly journals Iron oxide deposits associated with the ectosymbiotic bacteria in the hydrothermal vent shrimp <i>Rimicaris exoculata</i>

2008 ◽  
Vol 5 (5) ◽  
pp. 1295-1310 ◽  
Author(s):  
L. Corbari ◽  
M.-A. Cambon-Bonavita ◽  
G. J. Long ◽  
F. Grandjean ◽  
M. Zbinden ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Iron Oxides ◽  
Lower Layer ◽  
Minor Elements ◽  
Rimicaris Exoculata ◽  
Gill Chamber ◽  
Mid Atlantic Ridge ◽  
The Difference ◽  
Chemoautotrophic Bacteria ◽  
Hydrothermal Ecosystems

Abstract. The Rimicaris exoculata shrimp is considered as a primary consumer that dominates the fauna of most Mid-Atlantic Ridge (MAR) hydrothermal ecosystems. These shrimps harbour in their gill chambers an important ectosymbiotic community of chemoautotrophic bacteria associated with iron oxide deposits. The structure and elemental composition of the mineral concretions associated with these bacteria have been investigated by using LM, ESEM, TEM STEM and EDX microanalyses. The nature of the iron oxides in shrimps obtained from the Rainbow vent field has also been determined by Mössbauer spectroscopy. This multidisciplinary approach has revealed that the three layers of mineral crust in the Rimicaris exoculata shrimps consist of large concretions formed by aggregated nanoparticles of two-line ferrihydrite and include other minor elements as Si, Ca, Mg, S and P, probably present as silicates cations, sulphates or phosphates respectively that may contribute to stabilise the ferrihydrite form of iron oxides. TEM-observations on the bacteria have revealed their close interactions with these minerals. Abiotic and biotic precipitation could occur within the gill chamber of Rimicaris exoculata, suggesting the biologically-mediated formation of the iron oxide deposits. The difference of the bacterial density in the three-mineral crust layers could be correlated to the importance of the iron oxide concretions and suggest that the first mineral particles precipitates on the lower layer which could be considered as the most likely location of iron-oxidizing bacteria.

Observing the colloidal stability of iron oxide nanoparticlesin situ

Nanoscale ◽  
2019 ◽  
Vol 11 (27) ◽  
pp. 13098-13107 ◽  
Author(s):  
Ryan Hufschmid ◽  
Eric Teeman ◽  
B. Layla Mehdi ◽  
Kannan M. Krishnan ◽  
Nigel D. Browning
Keyword(s):  
Iron Oxide ◽  
Scanning Transmission Electron Microscopy ◽  
Colloidal Stability ◽  
Iron Oxide Nanoparticle ◽  
Nanoparticle Surface ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Liquid Cell ◽  
Oxide Nanoparticle

Iron oxide nanoparticle surface chemistry controls growth and dissolution, which are observed in real-time usingin situliquid cell Scanning Transmission Electron Microscopy (STEM).

scholarly journals Visualizing single atom dynamics in heterogeneous catalysis using analytical in situ environmental scanning transmission electron microscopy

2020 ◽  
Vol 378 (2186) ◽  
pp. 20190605
Author(s):  
Edward D. Boyes ◽  
Alec P. LaGrow ◽  
Michael R. Ward ◽  
Thomas E. Martin ◽  
Pratibha L. Gai
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Single Atom ◽  
Environmental Scanning ◽  
Technological Processes ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

Progress is reported in analytical in situ environmental scanning transmission electron microscopy (ESTEM) for visualizing and analysing in real-time dynamic gas–solid catalyst reactions at the single-atom level under controlled reaction conditions of gas environment and temperature. The recent development of the ESTEM advances the capability of the established ETEM with the detection of fundamental single atoms, and the associated atomic structure of selected solid-state heterogeneous catalysts, in catalytic reactions in their working state. The new data provide improved understanding of dynamic atomic processes and reaction mechanisms, in activity and deactivation, at the fundamental level; and in the chemistry underpinning important technological processes. The benefits of atomic resolution-E(S)TEM to science and technology include new knowledge leading to improved technological processes, reductions in energy requirements and better management of environmental waste. This article is part of a discussion meeting issue ‘Dynamic in situ microscopy relating structure and function’.

In Situ Imaging of Nano-Droplet Condensation and Coalescence on Thin Water Films

2013 ◽  
Vol 20 (2) ◽  
pp. 317-322 ◽  
Author(s):  
Zahava Barkay
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
Water Film ◽  
Dynamic Imaging ◽  
Environmental Scanning ◽  
Round Shape ◽  
Water Films ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Droplet Condensation

AbstractTwo related aspects of nano-droplet condensation and droplets coalescence are studied for droplets on self-supported thin water films. The experiments are conducted in the environmental scanning electron microscope using wet scanning transmission electron microscopy. Favorable condensation sites are examined and in-situ position-controlled condensation experiments are conducted. The interaction among condensed multi-droplets as well as between a single droplet and the underneath nano-thick water film are dynamically examined with 10nm lateral resolution. The droplet round shape is reshaped to flat-like facets in-between droplets of 30-230 nm separation. Dynamic imaging of a few minutes duration shows a delayed coalescence effect, being explained by increased droplet-droplet electrostatic interaction relative to van der Waals interaction.

scholarly journals Wet-STEM Tomography: Principles, Potentialities and Limitations

2014 ◽  
Vol 20 (2) ◽  
pp. 366-375 ◽  
Author(s):  
Karine Masenelli-Varlot ◽  
Annie Malchère ◽  
José Ferreira ◽  
Hamed Heidari Mezerji ◽  
Sara Bals ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Three Dimensional ◽  
Environmental Scanning Electron Microscopy ◽  
Inorganic Materials ◽  
Dimensional Structure ◽  
Environmental Scanning ◽  
Minimum Thickness ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Specific Device

AbstractThe characterization of biological and inorganic materials by determining their three-dimensional structure in conditions closer to their native state is a major challenge of technological research. Environmental scanning electron microscopy (ESEM) provides access to the observation of hydrated samples in water environments. Here, we present a specific device for ESEM in the scanning transmission electron microscopy mode, allowing the acquisition of tilt-series suitable for tomographic reconstructions. The resolution which can be obtained with this device is first determined. Then, we demonstrate the feasibility of tomography on wet materials. The example studied here is hydrophilic mesoporous silica (MCM-41). Finally, the minimum thickness of water which can be detected is calculated from Monte Carlo simulations and compared with the resolution expected in the tomograms.

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