 |
| Titel |
The future coastal ocean: the impact of increased stratification on biological production and carbon cycling |
| VerfasserIn |
Z. Lachkar, N. Gruber |
| Konferenz |
EGU General Assembly 2012
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250067614
|
|
|
|
|
|
| Zusammenfassung |
| Eastern boundary upwelling systems (EBUS) are regions of intense biogeochemical cycling
and air-sea CO2 exchange. EBUS are particularly sensitive to changes in vertical stratification
induced by upper ocean warming. However, neither the biological response to such physical
perturbation nor the extent to which air-sea CO2 exchange might be altered under increased
stratification are well understood. Here, we investigate the vulnerability of EBUS to such
changes by conducting eddy-resolving simulations with the Regional Oceanic Modeling
System (ROMS) coupled to a state-of-the art ecosystem model for the California and the
Canary Current Systems. We examine how potential changes in stratification might affect the
productivity in both upwelling systems and explore related changes in air-sea CO2 fluxes
and biological pump efficiency. A particular focus of our analyses is on the role
of local vs large scale changes in stratification. Overall, our initial results show
for both EBUS a substantial increase of the CO2 outgassing with only a relatively
modest change in productivity. We also found that identical changes in the vertical
stratification lead to contrasting biological responses within and between these two EBUS
characterized with only modestly different physical and environmental conditions. This is
essentially due to varying initial temperature and nutrient conditions in addition to
factors associated with the nearshore-offshore exchange timescales such as the
shelf topography and the level of mesoscale eddy activity which differ substantially
between the two EBUS. Finally, our results show that the depth of the maximum
warming as well as the vertical penetration of the warm temperature anomaly play a
key role in controlling the magnitude of the biological response in each EBUS. |
|
|
|
|
|
|