 |
| Titel |
Production of oceanic nitrous oxide by ammonia-oxidizing archaea |
| VerfasserIn |
C. R. Löscher, A. Kock, M. Könneke, J. LaRoche, H. W. Bange, R. A. Schmitz |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 9, no. 7 ; Nr. 9, no. 7 (2012-07-04), S.2419-2429 |
| Datensatznummer |
250007177
|
| Publikation (Nr.) |
 copernicus.org/bg-9-2419-2012.pdf |
|
|
|
|
|
| Zusammenfassung |
The recent finding that microbial ammonia oxidation in the ocean is
performed by archaea to a greater extent than by bacteria has drastically
changed the view on oceanic nitrification. The numerical dominance of
archaeal ammonia-oxidizers (AOA) over their bacterial counterparts (AOB) in
large parts of the ocean leads to the hypothesis that AOA rather than AOB
could be the key organisms for the oceanic production of the strong
greenhouse gas nitrous oxide (N2O) that occurs as a by-product of
nitrification. Very recently, enrichment cultures of marine
ammonia-oxidizing archaea have been reported to produce N2O.
Here, we demonstrate that archaeal ammonia monooxygenase genes (amoA) were
detectable throughout the water column of the eastern tropical North
Atlantic (ETNA) and eastern tropical South Pacific (ETSP) Oceans.
Particularly in the ETNA, comparable patterns of abundance and expression of
archaeal amoA genes and N2O co-occurred in the oxygen minimum, whereas the
abundances of bacterial amoA genes were negligible. Moreover, selective
inhibition of archaea in seawater incubations from the ETNA decreased the
N2O production significantly. In studies with the only cultivated
marine archaeal ammonia-oxidizer Nitrosopumilus maritimus SCM1, we provide the first direct evidence
for N2O production in a pure culture of AOA, excluding the involvement
of other microorganisms as possibly present in enrichments. N. maritimus showed high
N2O production rates under low oxygen concentrations comparable to
concentrations existing in the oxycline of the ETNA, whereas the N2O
production from two AOB cultures was comparably low under similar
conditions. Based on our findings, we hypothesize that the production of
N2O in tropical ocean areas results mainly from archaeal nitrification
and will be affected by the predicted decrease in dissolved oxygen in the
ocean. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|