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Titel |
Iron oxide deposits associated with the ectosymbiotic bacteria in the hydrothermal vent shrimp Rimicaris exoculata |
VerfasserIn |
L. Corbari, M.-A. Cambon-Bonavita, G. J. Long, F. Grandjean, M. Zbinden, F. Gaill, P. Compère |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1726-4170
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Digitales Dokument |
URL |
Erschienen |
In: Biogeosciences ; 5, no. 5 ; Nr. 5, no. 5 (2008-09-10), S.1295-1310 |
Datensatznummer |
250002827
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Publikation (Nr.) |
copernicus.org/bg-5-1295-2008.pdf |
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Zusammenfassung |
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. |
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