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| Titel |
MOPS-1.0: towards a model for the regulation of the global oceanic nitrogen budget by marine biogeochemical processes |
| VerfasserIn |
I. Kriest, A. Oschlies |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1991-959X
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| Digitales Dokument |
URL |
| Erschienen |
In: Geoscientific Model Development ; 8, no. 9 ; Nr. 8, no. 9 (2015-09-23), S.2929-2957 |
| Datensatznummer |
250116561
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| Publikation (Nr.) |
 copernicus.org/gmd-8-2929-2015.pdf |
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| Zusammenfassung |
| Global models of the oceanic nitrogen cycle are subject to many
uncertainties regarding the representation of the relevant
biogeochemical processes
and of the feedbacks between nitrogen sources and sinks that determine space- and timescales
on which the global nitrogen budget is regulated. We
investigate these aspects using a global model of ocean
biogeochemistry that explicitly considers phosphorus and nitrogen,
including pelagic denitrification and nitrogen fixation as sink and source
terms of fixed nitrogen, respectively. The model explores different
parameterizations of organic matter sinking speed, oxidant affinity
of oxic and suboxic remineralization, and regulation of nitrogen
fixation by temperature and different stoichiometric ratios.
Examination of the initial transient behavior of
different model setups initialized from observed biogeochemical tracer distributions reveal
changes in simulated nitrogen inventories and fluxes particularly during the first
centuries. Millennial timescales have to be resolved in order to
bring all biogeochemical and physical processes into
a dynamically consistent steady state.
Analysis of global properties
suggests that not only particularly particle sinking speed but also the
parameterization of denitrification determine the extent of oxygen
minimum zones, global nitrogen fluxes, and hence the oceanic nitrogen
inventory. However, the
ways and directions in which different
parameterizations
of particle sinking, nitrogen fixation, and denitrification affect the global diagnostics are different
suggesting that these
may, in principle, be constrained independently from each other.
Analysis of the model misfit with respect to observed biogeochemical tracer distributions and fluxes suggests a particle flux
profile close to the one suggested by Martin et al. (1987).
Simulated pelagic denitrification best agrees with the lower values between 59 and 84 Tg N yr−1
recently
estimated by other authors. |
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