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| Titel |
Stimulation of microbial nitrogen cycling in aquatic ecosystems by benthic macrofauna: mechanisms and environmental implications |
| VerfasserIn |
P. Stief |
| 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 ; 10, no. 12 ; Nr. 10, no. 12 (2013-12-02), S.7829-7846 |
| Datensatznummer |
250085451
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| Publikation (Nr.) |
 copernicus.org/bg-10-7829-2013.pdf |
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| Zusammenfassung |
| Invertebrate animals that live at the bottom of aquatic ecosystems (i.e.,
benthic macrofauna) are important mediators between nutrients in the water
column and microbes in the benthos. The presence of benthic macrofauna
stimulates microbial nutrient dynamics through different types of
animal–microbe interactions, which potentially affect the trophic status of
aquatic ecosystems. This review contrasts three types of animal–microbe
interactions in the benthos of aquatic ecosystems: (i) ecosystem
engineering, (ii) grazing, and (iii) symbiosis. Their specific contributions
to the turnover of fixed nitrogen (mainly nitrate and ammonium) and the
emission of the greenhouse gas nitrous oxide are evaluated.
Published data indicate that ecosystem engineering by sediment-burrowing
macrofauna stimulates benthic nitrification and denitrification, which
together allows fixed nitrogen removal. However, the release of ammonium
from sediments is enhanced more strongly than the sedimentary uptake of nitrate.
Ecosystem engineering by reef-building macrofauna increases nitrogen
retention and ammonium concentrations in shallow aquatic ecosystems, but
allows organic nitrogen removal through harvesting. Grazing by macrofauna on
benthic microbes apparently has small or neutral effects on nitrogen
cycling. Animal–microbe symbioses provide abundant and distinct benthic
compartments for a multitude of nitrogen-cycle pathways. Recent studies
reveal that ecosystem engineering, grazing, and symbioses of benthic
macrofauna significantly enhance nitrous oxide emission from shallow aquatic
ecosystems.
The beneficial effect of benthic macrofauna on fixed nitrogen removal
through coupled nitrification–denitrification can thus be offset by the
concurrent release of (i) ammonium that stimulates aquatic primary
production and (ii) nitrous oxide that contributes to global warming.
Overall, benthic macrofauna intensifies the coupling between benthos,
pelagial, and atmosphere through enhanced turnover and transport of
nitrogen. |
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