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| Titel |
Seasonal variability of fCO2 in the eastern North Atlantic Ocean |
| VerfasserIn |
Anna Barrera-Galderique, Melchor González-Dávila, J. Magdalena Santana-Casiano |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250056688
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| Zusammenfassung |
| Monthly measurements of fCO2, temperature, salinity and chlorophyll a were analyzed from
July 2005 to April 2008 for the studied area located at the northwest European
shelf from 40ºN 10º W to 52ºN 2ºE using volunteer observing ships (VOS). The
objective was to gauge the seasonal variability of fCO2 in surface seawaters, and the
seasonal air-sea CO2 exchange, taking into account the latitudinal transition of relative
importance in the temperature and the biological effects on seawater fCO2 variability,
and the dynamic of the upwelling that affects the air-sea fluxes of CO2. Due to
the area of the study covered different hydrographical conditions, the area was
divided into three regions. The results showed a complex surface hydrodynamic
system, with coast upwelling, vertical mixing processes and fronts affecting the
physical, chemical and biological parameters that control the surface distribution
of fCO2. The Galician coast region (40ºN-43.5ºN) acted as an active sink, with
a rate of oceanic CO2 uptake of -2.86 ± 0.69 mol m-2 yr-1 in 2006 and -3.75
± 0.78 mol m-2 yr-1 in 2007. Moreover, in upwelling periods, SST decreased
by over 6ºC and fCO2 was strongly affected, indicating that both solubility and
biological uptake effects are compensating upwelled CO2 rich water. Blooms of
phytoplankton reduced the fCO2 in the area. The Biscay Bay region (43.5ºN-48.5ºN)
also acted as a homogenous sink of CO2, with fluxes of -3.79 ± 0.57 mol m-2
yr-1 in 2007. However, in 2006, the CO2 fluxes were closer to equilibrium. These
results were explained by changes in the wind fields, with very low wind speeds
during 2006, while fCO2 gradients kept relatively constant. The English Channel
region (48.5ºN-52ºN) presented the highest variability observed that indicated the
strong influence by river inputs, biological events and the fronts, acting as a sink in
winter and spring and as a source in summer and autumn. Annually, the western
English Channel acted as a variable source of CO2, with fluxes of 0.53 ± 2.50 mol
m-2 yr-1 in 2006 and 0.70 ± 2.78 mol m-2 yr-1 in 2007, while in the eastern
English Channel acted as an important sink of CO2, with fluxes of -5.95 ± 3.97 mol
m-2 yr-1 in 2007, with a strong influence of the biological effects on the area. |
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