Abstract
The immobilization of silica and iron by the bacteria Bacillus subtilis was monitored in controlled microcosms to elucidate the role iron may play in aiding bacterial silicification in hot springs. Silica and iron immobilization was monitored as a function of bacterial concentration, iron concentration, and silica concentration (both undersaturated and oversaturated with respect to amorphous silica). Results demonstrate that bacterial cells do immobilize more Fe than bacteria-free systems in solutions with iron concentrations ≤50 ppm Fe. However, as iron concentrations increase, the difference between Fe immobilization in bacterial and bacteria-free systems decreases as non-bacterially mediated precipitation processes dominate. Additionally, bacterial systems that had immobilized more Fe compared with bacteria-free systems did not immobilize more silica than bacteria-free systems. By comparing molar ratios of (silica in solution)/(bacterially bound Fe), it is evident that insufficient iron is bound to the bacterial surface to act as an effective salt bridge for silica sorption. This appears to be because much of the iron is immobilized by non-bacterially mediated precipitation of phases such as Fe(OH)3 and poorly ordered hydrous iron silicates. It follows that in silica-enriched hot springs, silica and iron immobilization processes are significantly dominated by non-bacterially mediated precipitation. Any bacterially mediated processes are exceedingly small and outside the resolution of these experiments.
| Language | English |
|---|---|
| Pages | 1669-1678 |
| Number of pages | 10 |
| Journal | Canadian Journal of Earth Sciences |
| Volume | 40 |
| Issue number | 11 |
| DOIs | |
| Publication status | Published - 30 Nov 2003 |
| Externally published | Yes |
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Keywords
- bacterial silicification
- bacterial systems
- hot spring
Cite this
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Experimental study of iron and silica immobilization by bacteria in mixed Fe-Si systems : implications for microbial silicification in hot springs. / Phoenix, Vernon R; Konhauser, Kurt O; Ferris, F Grant.
In: Canadian Journal of Earth Sciences, Vol. 40, No. 11, 30.11.2003, p. 1669-1678.Research output: Contribution to journal › Article
TY - JOUR
T1 - Experimental study of iron and silica immobilization by bacteria in mixed Fe-Si systems
T2 - Canadian Journal of Earth Sciences
AU - Phoenix, Vernon R
AU - Konhauser, Kurt O
AU - Ferris, F Grant
PY - 2003/11/30
Y1 - 2003/11/30
N2 - The immobilization of silica and iron by the bacteria Bacillus subtilis was monitored in controlled microcosms to elucidate the role iron may play in aiding bacterial silicification in hot springs. Silica and iron immobilization was monitored as a function of bacterial concentration, iron concentration, and silica concentration (both undersaturated and oversaturated with respect to amorphous silica). Results demonstrate that bacterial cells do immobilize more Fe than bacteria-free systems in solutions with iron concentrations ≤50 ppm Fe. However, as iron concentrations increase, the difference between Fe immobilization in bacterial and bacteria-free systems decreases as non-bacterially mediated precipitation processes dominate. Additionally, bacterial systems that had immobilized more Fe compared with bacteria-free systems did not immobilize more silica than bacteria-free systems. By comparing molar ratios of (silica in solution)/(bacterially bound Fe), it is evident that insufficient iron is bound to the bacterial surface to act as an effective salt bridge for silica sorption. This appears to be because much of the iron is immobilized by non-bacterially mediated precipitation of phases such as Fe(OH)3 and poorly ordered hydrous iron silicates. It follows that in silica-enriched hot springs, silica and iron immobilization processes are significantly dominated by non-bacterially mediated precipitation. Any bacterially mediated processes are exceedingly small and outside the resolution of these experiments.
AB - The immobilization of silica and iron by the bacteria Bacillus subtilis was monitored in controlled microcosms to elucidate the role iron may play in aiding bacterial silicification in hot springs. Silica and iron immobilization was monitored as a function of bacterial concentration, iron concentration, and silica concentration (both undersaturated and oversaturated with respect to amorphous silica). Results demonstrate that bacterial cells do immobilize more Fe than bacteria-free systems in solutions with iron concentrations ≤50 ppm Fe. However, as iron concentrations increase, the difference between Fe immobilization in bacterial and bacteria-free systems decreases as non-bacterially mediated precipitation processes dominate. Additionally, bacterial systems that had immobilized more Fe compared with bacteria-free systems did not immobilize more silica than bacteria-free systems. By comparing molar ratios of (silica in solution)/(bacterially bound Fe), it is evident that insufficient iron is bound to the bacterial surface to act as an effective salt bridge for silica sorption. This appears to be because much of the iron is immobilized by non-bacterially mediated precipitation of phases such as Fe(OH)3 and poorly ordered hydrous iron silicates. It follows that in silica-enriched hot springs, silica and iron immobilization processes are significantly dominated by non-bacterially mediated precipitation. Any bacterially mediated processes are exceedingly small and outside the resolution of these experiments.
KW - bacterial silicification
KW - bacterial systems
KW - hot spring
UR - http://www.scopus.com/inward/record.url?scp=1542378113&partnerID=8YFLogxK
UR - http://www.nrcresearchpress.com/journal/cjes
U2 - 10.1139/e03-044
DO - 10.1139/e03-044
M3 - Article
VL - 40
SP - 1669
EP - 1678
JO - Canadian Journal of Earth Sciences
JF - Canadian Journal of Earth Sciences
SN - 0008-4077
IS - 11
ER -