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| Titel |
Organo-mineral complexation alters carbon and nitrogen cycling in stream microbial assemblages |
| VerfasserIn |
William Ross Hunter, Wolfgang Wanek, Judith Prommer, Maria Mooshammer, Tom Battin |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250089171
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| Publikation (Nr.) |
 EGU/EGU2014-3364.pdf |
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| Zusammenfassung |
| Inland waters are of global biogeochemical importance receiving carbon inputs of ~ 4.8 Pg C
y-1. Of this 12 % is buried, 18 % transported to the oceans, and 70 % supports aquatic
secondary production. However, the mechanisms that determine the fate of organic matter
(OM) in these systems are poorly defined. One important aspect is the formation of
organo-mineral complexes in aquatic systems and their potential as a route for OM transport
and burial vs. microbial utilization as organic carbon (C) and nitrogen (N) sources.
Organo-mineral particles form by sorption of dissolved OM to freshly eroded mineral
surfaces and may contribute to ecosystem-scale particulate OM fluxes. We tested the
availability of mineral-sorbed OM as a C & N source for streamwater microbial assemblages
and streambed biofilms. Organo-mineral particles were constructed in vitro by sorption of
13C:15N-labelled amino acids to hydrated kaolin particles, and microbial degradation of these
particles compared with equivalent doses of 13C:15N-labelled free amino acids.
Experiments were conducted in 120 ml mesocosms over 7 days using biofilms and
streamwater sampled from the Oberer Seebach stream (Austria), tracing assimilation and
mineralization of 13C and 15N labels from mineral-sorbed and dissolved amino
acids.
Here we present data on the effects of organo-mineral sorption upon amino acid
mineralization and its C:N stoichiometry. Organo-mineral sorption had a significant effect
upon microbial activity, restricting C and N mineralization by both the biofilm and
streamwater treatments. Distinct differences in community response were observed, with both
dissolved and mineral-stabilized amino acids playing an enhanced role in the metabolism of
the streamwater microbial community. Mineral-sorption of amino acids differentially affected
C & N mineralization and reduced the C:N ratio of the dissolved amino acid pool. The
present study demonstrates that organo-mineral complexes restrict microbial degradation of
OM and may, consequently, alter the carbon and nitrogen cycling dynamics within aquatic
ecosystems. |
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