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| Titel |
NW European shelf productivity under climate warming: Implications for shelf carbon absorption |
| VerfasserIn |
M. Gröger, E. Maier-Reimer, U. Mikolajewicz, D. Sein |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250063843
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| Zusammenfassung |
| Shelves have been estimated to account for more than one third of the global marine primary
production. Enhanced biological productivity and carbon fixation on shelves is assumed by
several authors to play a key role for both, the economic basis for industrial fishery and the
oceanic absorption of atmospheric CO2. In model climate projections we find that already a
moderate warming of 1.7 to 2.0 K of the sea surface reduces biological production on the NW
European shelf by ~35%. This reduction is twice as strong as the reduction in the open
ocean. Shelf productivity is thus much more vulnerable to climate warming than the
open ocean productivity. The underlying mechanism is a spatially well confined
stratification feedback along the continental shelf break which reduces the nutrient
supply from the deep Atlantic by up to 50% with subsequent reductions in biological
activity.
Carbon absorption on the NW European shelf decreases by 1/3 at the end of the 21st century
compared to the end of the 20th century implying a strong weakening of shelf carbon
pumping. Diagnostic tracer experiments indicate, however, that shelf sea pumping
plays not an essential role in removing CO2 from the atmosphere because most
water exported to the open ocean remains within the mixed layer where it is still
exposed to the atmosphere. For the North Sea we estimate that only ~20% of the
absorbed carbon has the potential for long term sequestration in the open ocean. |
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