 |
| Titel |
Mass, nutrient and oxygen budgets for the northeastern Atlantic Ocean |
| VerfasserIn |
G. Maze, H. Mercier, V. Thierry, L. Memery, P. Morin, F. F. Pérez |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 9, no. 10 ; Nr. 9, no. 10 (2012-10-24), S.4099-4113 |
| Datensatznummer |
250007341
|
| Publikation (Nr.) |
 copernicus.org/bg-9-4099-2012.pdf |
|
|
|
|
|
| Zusammenfassung |
The northeast Atlantic is a key horizontal and vertical crossroads region
for the meridional overturning circulation, but basic nutrient and oxygen
fluxes are still poorly constrained by observations in the region. A surface
to bottom northeast Atlantic Ocean budget for mass, nutrients (nitrate and
phosphate) and oxygen is determined using an optimization method based on
three surveys of the OVIDE transect (from Greenland to Portugal) completed
with the World Ocean Atlas 2009. Budgets are derived for two communicating
boxes representing the northeastern European basin (NEEB) and the Irminger
Sea.
For the NEEB (Irminger) box, it is found that 30% of the mass import
(export) across the OVIDE section reach (originate from) the Nordic Seas,
while 70% are redistributed between both boxes through the Reykjanes
Ridge (9.3 ± 0.7 × 109 kg s−1).
Net biological source/sink terms of nitrate point to both the Irminger and
NEEB boxes as net organic matter production sites (consuming nitrate at a
rate of –7.8 ± 6.5 kmol s−1 and
–8.4 ± 6.6 kmol s−1, respectively). Using a standard Redfield
ratio of C : N = 106 : 16, nitrate consumption rates indicate that about
40 TgC yr−1 of carbon is fixed by organic matter production
between the OVIDE transect and the Greenland–Scotland Ridge. Nutrient fluxes
also induce a net biological production of oxygen of
73 ± 60 kmol s−1 and 79 ± 62 kmol s−1 in the
Irminger and NEEB boxes, which points to the region as being autotrophic.
The abiotic air–sea oxygen flux leads to an oceanic oxygen uptake in the two
regions (264 ± 66 kmol s−1 in the north and
443 ± 70 kmol s−1 in the south). The abiotic flux is
partitioned into a mixing and a thermal component. It is found that the
Irminger Sea oceanic oxygen uptake is driven by an air–sea heat flux cooling
increasing the ocean surface oxygen solubility. Over the northeastern
European basin the mixing component is about half the thermal flux,
presumably because of the oxygen minimum in the subtropical thermocline. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|