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| Titel |
Influence of bioturbation on the biogeochemistry of littoral sediments of an acidic post-mining pit lake |
| VerfasserIn |
S. Lagauzère, S. Moreira, M. Koschorreck |
| 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 ; 8, no. 2 ; Nr. 8, no. 2 (2011-02-14), S.339-352 |
| Datensatznummer |
250005446
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| Publikation (Nr.) |
 copernicus.org/bg-8-339-2011.pdf |
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| Zusammenfassung |
| In the last decades, the mining exploitation of large areas in Lusatia
(Eastern Germany) but also in other mining areas worldwide has led to the
formation of hundreds of pit lakes. Pyrite oxidation in the surrounding
dumps makes many such lakes extremely acidic (pH < 3). The biogeochemical
functioning of these lakes is mainly governed by cycling of iron. This
represents a relevant ecological problem and intensive research has been
conducted to understand the involved biogeochemical processes and develop
bioremediation strategies. Despite some studies reporting the presence of
living organisms (mostly bacteria, algae, and macro-invertebrates) under
such acidic conditions, and their trophic interactions, their potential
impact on the ecosystem functioning was poorly investigated. The present
study aimed to assess the influence of chironomid larvae on oxygen dynamics
and iron cycle in the sediment of acidic pit lakes. In the Mining Lake 111,
used as a study case since 1996, Chironomus crassimanus (Insecta, Diptera) is the dominant benthic
macro-invertebrate species and occurs at relatively high abundances in
shallow water. A 16-day laboratory experiment using microcosms combined with
high resolution measurements (DET gel probes and O2 microsensors) was
carried out. The burrowing activity of C. crassimanus larvae induced a 3-fold increase of
the diffusive oxygen uptake by sediment, indicating a stimulation of the
mineralization of organic matter in the upper layers of the sediment. The
iron cycle was also impacted (e.g. lower rates of reduction and oxidation,
increase of iron-oxidizing bacteria abundance, stimulation of mineral
formation) but with no significant effect on the iron flux at the
sediment-water interface, and thus on the water acidity budget. This work
provides the first assessment of bioturbation in an acidic mining lake and
shows that its influence on biogeochemistry cannot be neglected. |
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