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| Titel |
Oceanic controls on the primary production of the northwest European continental shelf: model experiments under recent past conditions and a potential future scenario |
| VerfasserIn |
J. Holt, M. Butenschön, S. L. Wakelin, Y. Artioli, J. I. Allen |
| 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 ; 9, no. 1 ; Nr. 9, no. 1 (2012-01-06), S.97-117 |
| Datensatznummer |
250006654
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| Publikation (Nr.) |
 copernicus.org/bg-9-97-2012.pdf |
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| Zusammenfassung |
| In this paper we clearly demonstrate that changes in oceanic nutrients are a
first order factor in determining changes in the primary production of the
northwest European continental shelf on time scales of 5–10 yr. We
present a series of coupled hydrodynamic ecosystem modelling simulations,
using the POLCOMS-ERSEM system. These are forced by both reanalysis data
and a single example of a coupled ocean-atmosphere general circulation model
(OA-GCM) representative of possible conditions in 2080–2100 under an SRES
A1B emissions scenario, along with the corresponding present day control.
The OA-GCM forced simulations show a substantial reduction in surface
nutrients in the open-ocean regions of the model domain, comparing future
and present day time-slices. This arises from a large increase in oceanic
stratification. Tracer transport experiments identify a substantial fraction
of on-shelf water originates from the open-ocean region to the south of the
domain, where this increase is largest, and indeed the on-shelf nutrient and
primary production are reduced as this water is transported on-shelf. This
relationship is confirmed quantitatively by comparing changes in winter
nitrate with total annual nitrate uptake. The reduction in primary
production by the reduced nutrient transport is mitigated by on-shelf
processes relating to temperature, stratification (length of growing season)
and recycling. Regions less exposed to ocean-shelf exchange in this model
(Celtic Sea, Irish Sea, English Channel, and Southern North Sea) show a
modest increase in primary production (of 5–10%) compared with a decrease
of 0–20% in the outer shelf, Central and Northern North Sea. These
findings are backed up by a boundary condition perturbation experiment and a
simple mixing model. |
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