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| Titel |
In vitro formation of Ca-oxalates and the mineral glushinskite by fungal interaction with carbonate substrates and seawater |
| VerfasserIn |
K. Kolo, Ph. Claeys |
| 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 ; 2, no. 3 ; Nr. 2, no. 3 (2005-10-26), S.277-293 |
| Datensatznummer |
250000623
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| Publikation (Nr.) |
 copernicus.org/bg-2-277-2005.pdf |
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| Zusammenfassung |
| This study investigates the in vitro formation of Ca-oxalates and glushinskite
through fungal interaction with carbonate substrates and seawater as a
process of biologically induced metal recycling and neo-mineral formation.
The study also emphasizes the role of the substrates as metal donors. In the
first experiment, thin sections prepared from dolomitic rock samples of
Terwagne Formation (Carboniferous, Viséan, northern France) served as
substrates. The thin sections placed in Petri dishes were exposed to fungi
grown from naturally existing airborne spores. In the second experiment,
fungal growth and mineral formation was monitored using only standard
seawater (SSW) as a substrate. Fungal growth media consisted of a high
protein/carbohydrates and sugar diet with demineralized water for
irrigation. Fungal growth process reached completion under uncontrolled
laboratory conditions. The newly formed minerals and textural changes caused
by fungal attack on the carbonate substrates were investigated using light
and scanning electron microscopy (SEM-EDX), x-ray diffraction (XRD) and
Raman spectroscopy. The fungal interaction and attack on the dolomitic and
seawater substrates resulted in the formation of Ca-oxalates (weddellite
CaC2O4·2(H2O), whewellite
(CaC2O4·(H2O)) and glushinskite MgC2O4·2(H2O) associated with the destruction of the original hard substrates
and their replacement by the new minerals. Both of Ca and Mg were mobilized
from the experimental substrates by fungi. This metal mobilization involved
a recycling of substrate metals into newly formed minerals. The biochemical
and diagenetic results of the interaction strongly marked the attacked
substrates with a biological fingerprint. Such fingerprints are biomarkers
of primitive life. The formation of glushinskite is of specific importance
that is related, besides its importance as a biomineral bearing a recycled
Mg, to the possibility of its transformation through diagenetic pathway into
an Mg carbonate. This work is the first report on the in vitro formation of the
mineral glushinskite through fungal interaction with carbonate and seawater
substrates. Besides recording the detailed Raman signature of various
crystal habits of Mg- and Ca-oxalates, the Raman spectroscopy proved two new
crystal habits for glushinskite. The results of this work document the role
of microorganisms as metal recyclers in biomineralization, neo-mineral
formation, sediment diagenesis, bioweathering and in the production of
mineral and diagenetic biomarkers. They also reveal the capacity of living
fungi to interact with liquid substrates and precipitate new minerals. |
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