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| Titel |
The role of polysaccharides and diatom exudates in the redox cycling of Fe and the photoproduction of hydrogen peroxide in coastal seawaters |
| VerfasserIn |
S. Steigenberger, P. J. Statham, C. Völker, U. Passow |
| 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 ; 7, no. 1 ; Nr. 7, no. 1 (2010-01-11), S.109-119 |
| Datensatznummer |
250004368
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| Publikation (Nr.) |
 copernicus.org/bg-7-109-2010.pdf |
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| Zusammenfassung |
| The effect of artificial acidic polysaccharides (PS) and exudates of
Phaeodactylum tricornutum on the half-life of Fe(II) in seawater was investigated in laboratory
experiments. Strong photochemical hydrogen peroxide (H2O2)
production of 5.2 to 10.9 nM (mg C)−1 h−1 was found in the
presence of PS and diatom exudates. Furthermore when illuminated with UV
light the presence of algal exudates had a net stabilising effect on ferrous
iron in seawater (initial value 100 nmol L−1) above that expected from
oxidation kinetics. In the dark the PS gum xanthan showed no stabilising
effect on Fe(II). The photochemical formation of superoxide (O2−)
in the presence of diatom exudates and its reducing effect on Fe(III)
appears to result in greater than expected concentrations of Fe(II). A model
of the photochemical redox cycle of iron incorporating these processes
supported the observed data well. Diatom exudates seem to have the potential
to play an important role for the photochemistry of iron in coastal waters. |
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