 |
| Titel |
An eddy-stimulated hotspot for fixed nitrogen-loss from the Peru oxygen minimum zone |
| VerfasserIn |
M. A. Altabet, E. Ryabenko, L. Stramma, D. W. R. Wallace, M. Frank, P. Grasse, G. Lavik |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 9, no. 12 ; Nr. 9, no. 12 (2012-12-03), S.4897-4908 |
| Datensatznummer |
250007446
|
| Publikation (Nr.) |
 copernicus.org/bg-9-4897-2012.pdf |
|
|
|
|
|
| Zusammenfassung |
| Fixed nitrogen (N) loss to biogenic N2 in intense oceanic O2
minimum zones (OMZ) accounts for a large fraction of the global N sink and
is an essential control on the ocean's N-budget. However, major
uncertainties exist regarding microbial pathways as well as net impact on
the magnitude of N-loss and the ocean's overall N-budget. Here we report the
discovery of a N-loss hotspot in the Peru OMZ associated with a coastally
trapped mesoscale eddy that is marked by an extreme N-deficit matched by
biogenic N2 production, high NO2− levels, and the highest
isotope enrichments observed so far in OMZ's for the residual
NO3−. High sea surface chlorophyll in seaward flowing
streamers provides evidence for offshore eddy transport of highly
productive, inshore water. Resulting pulses in the downward flux of
particles likely stimulated heterotrophic dissimilatory NO3−
reduction and subsequent production of biogenic N2 within the OMZ. A
shallower biogenic N2 maximum within the oxycline is likely a feature
advected by the eddy streamer from the shelf. Eddy-associated
temporal-spatial heterogeneity of N-loss, mediated by a local succession of
microbial processes, may explain inconsistencies observed among prior
studies. Similar transient enhancements of N-loss likely occur within all
other major OMZ's exerting a major influence on global ocean N and N isotope
budgets. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|